From nobody Sat Feb 7 15:22:00 2026 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D3BE32459CF; Wed, 28 Jan 2026 14:09:16 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769609356; cv=none; b=Tq9Vg9i84NpzanDEvKXC3SYhwLmM2AZOXPo8DSqyFcyEWS6/gsshqx03+GPIPWIKCqqB/OassSzYkEVngdbpijdduR56IUGMN2J0cWZccIXZKyPpmFR76ob5SHIyF0CkW5LJYuSmPea4dKZl6iGQAJXwSgMPMVcaw37i0/D1KYo= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769609356; c=relaxed/simple; bh=OGQdijVJco9ownoaz2i35yald20nK+gkhFOfqRVTuQo=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=ig4u82I/S1uqIGoDOQl9pNBnIsbgQ6BMOKffHsbDQEtNSnFeDDOXnG0aR+DboD2DEi9ZJTw/rW0l2xx5V1BC6LDPF8tXh/1a0J/5eV6BhN+ESAUl8j0HVGMQkNiQBPwGzRsONBMLtTjbuaoKoEf/eT6ommAQBiC4rRo/8DTlzgA= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=q0JwXW8F; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="q0JwXW8F" Received: by smtp.kernel.org (Postfix) with ESMTPSA id F3FD4C4CEF1; Wed, 28 Jan 2026 14:09:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1769609356; bh=OGQdijVJco9ownoaz2i35yald20nK+gkhFOfqRVTuQo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=q0JwXW8FG6JAxiZL26ZguLD199FK2YhlprMsqdQnbZjZZSFPkLR8aBhXFyz5sjCSx Du7gts9mY8Zh8RmBXRd+BZIXA6jg3tr00GC7OOr4axmquOWciy5Q78Suxpcp598F97 6z7ytmarPMnBFMYWigCW06lbfgmaoqgMgpyKdHfH1FjF6A8PJA2FZhA91rPuawLp/4 HgfxzEaDXNvskmE8/PbzbJzz0hTQP63wKwgyv7uInhmoaXBwFSO7ELjk9gzVK0tOSB bGzsjMvuSHVjjPpdFSVN3b47NxjJmKMI5V8C4u7qRrGbDITP4ummDVXCHdWUUdXurW QwqG1w2q741/A== From: "Masami Hiramatsu (Google)" To: Steven Rostedt , Peter Zijlstra , Ingo Molnar , x86@kernel.org Cc: Jinchao Wang , Mathieu Desnoyers , Masami Hiramatsu , Thomas Gleixner , Borislav Petkov , Dave Hansen , "H . Peter Anvin" , Alexander Shishkin , Ian Rogers , linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-perf-users@vger.kernel.org Subject: [PATCH v6 01/11] tracing: wprobe: Add watchpoint probe event based on hardware breakpoint Date: Wed, 28 Jan 2026 23:09:10 +0900 Message-ID: <176960935044.182525.6102102342601102946.stgit@devnote2> X-Mailer: git-send-email 2.43.0 In-Reply-To: <176960933881.182525.11984731584313026309.stgit@devnote2> References: <176960933881.182525.11984731584313026309.stgit@devnote2> User-Agent: StGit/0.19 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable From: Masami Hiramatsu (Google) Add a new probe event for the hardware breakpoint called wprobe-event. This wprobe allows user to trace (watch) the memory access at the specified memory address. The new syntax is; w[:[GROUP/]EVENT] [r|w|rw]@[ADDR|SYM][:SIZE] [FETCH_ARGs] User also can use $addr to fetch the accessed address. But no other variables are supported. To record updated value, use '+0($addr)'. For example, tracing updates of the jiffies; /sys/kernel/tracing # echo 'w:my_jiffies w@jiffies' >> dynamic_events /sys/kernel/tracing # cat dynamic_events w:wprobes/my_jiffies w@jiffies:4 /sys/kernel/tracing # echo 1 > events/wprobes/my_jiffies/enable /sys/kernel/tracing # head -n 20 trace | tail -n 5 # TASK-PID CPU# ||||| TIMESTAMP FUNCTION # | | | ||||| | | -0 [000] d.Z1. 206.547317: my_jiffies: (tick_do_upd= ate_jiffies64+0xbe/0x130) -0 [000] d.Z1. 206.548341: my_jiffies: (tick_do_upd= ate_jiffies64+0xbe/0x130) -0 [000] d.Z1. 206.549346: my_jiffies: (tick_do_upd= ate_jiffies64+0xbe/0x130) Link: https://lore.kernel.org/all/175859021100.374439.8723137923620348816.s= tgit@devnote2/ Signed-off-by: Masami Hiramatsu (Google) --- Documentation/trace/index.rst | 1=20 Documentation/trace/wprobetrace.rst | 69 ++++ include/linux/trace_events.h | 2=20 kernel/trace/Kconfig | 13 + kernel/trace/Makefile | 1=20 kernel/trace/trace.c | 9=20 kernel/trace/trace.h | 5=20 kernel/trace/trace_probe.c | 22 + kernel/trace/trace_probe.h | 8=20 kernel/trace/trace_wprobe.c | 685 +++++++++++++++++++++++++++++++= ++++ 10 files changed, 812 insertions(+), 3 deletions(-) create mode 100644 Documentation/trace/wprobetrace.rst create mode 100644 kernel/trace/trace_wprobe.c diff --git a/Documentation/trace/index.rst b/Documentation/trace/index.rst index b4a429dc4f7a..14de6858ae1b 100644 --- a/Documentation/trace/index.rst +++ b/Documentation/trace/index.rst @@ -36,6 +36,7 @@ the Linux kernel. kprobes kprobetrace fprobetrace + wprobetrace eprobetrace fprobe ring-buffer-design diff --git a/Documentation/trace/wprobetrace.rst b/Documentation/trace/wpro= betrace.rst new file mode 100644 index 000000000000..025b4c39b809 --- /dev/null +++ b/Documentation/trace/wprobetrace.rst @@ -0,0 +1,69 @@ +.. SPDX-License-Identifier: GPL-2.0 + +=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D +Watchpoint probe (wprobe) Event Tracing +=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D + +.. Author: Masami Hiramatsu + +Overview +-------- + +Wprobe event is a dynamic event based on the hardware breakpoint, which is +similar to other probe events, but it is for watching data access. It allo= ws +you to trace which code accesses a specified data. + +As same as other dynamic events, wprobe events are defined via +`dynamic_events` interface file on tracefs. + +Synopsis of wprobe-events +------------------------- +:: + + w:[GRP/][EVENT] SPEC [FETCHARGS] : Probe on data a= ccess + + GRP : Group name for wprobe. If omitted, use "wprobes" for it. + EVENT : Event name for wprobe. If omitted, an event name is + generated based on the address or symbol. + SPEC : Breakpoint specification. + [r|w|rw]@[:LENGTH] + + r|w|rw : Access type, r for read, w for write, and rw for both. + Default is rw if omitted. + ADDRESS : Address to trace (hexadecimal). + SYMBOL : Symbol name to trace. + LENGTH : Length of the data to trace in bytes. (1, 2, 4, or 8) + + FETCHARGS : Arguments. Each probe can have up to 128 args. + $addr : Fetch the accessing address. + @ADDR : Fetch memory at ADDR (ADDR should be in kernel) + @SYM[+|-offs] : Fetch memory at SYM +|- offs (SYM should be a data symbo= l) + +|-[u]OFFS(FETCHARG) : Fetch memory at FETCHARG +|- OFFS address.(\*1)(\= *2) + \IMM : Store an immediate value to the argument. + NAME=3DFETCHARG : Set NAME as the argument name of FETCHARG. + FETCHARG:TYPE : Set TYPE as the type of FETCHARG. Currently, basic types + (u8/u16/u32/u64/s8/s16/s32/s64), hexadecimal types + (x8/x16/x32/x64), "char", "string", "ustring", "symbol",= "symstr" + and bitfield are supported. + + (\*1) this is useful for fetching a field of data structures. + (\*2) "u" means user-space dereference. + +For the details of TYPE, see :ref:`kprobetrace documentation `. + +Usage examples +-------------- +Here is an example to add a wprobe event on a variable `jiffies`. +:: + + # echo 'w:my_jiffies w@jiffies' >> dynamic_events + # cat dynamic_events + w:wprobes/my_jiffies w@jiffies + # echo 1 > events/wprobes/enable + # cat trace | head + # TASK-PID CPU# ||||| TIMESTAMP FUNCTION + # | | | ||||| | | + -0 [000] d.Z1. 717.026259: my_jiffies: (tick_do_up= date_jiffies64+0xbe/0x130) + -0 [000] d.Z1. 717.026373: my_jiffies: (tick_do_up= date_jiffies64+0xbe/0x130) + +You can see the code which writes to `jiffies` is `tick_do_update_jiffies6= 4()`. diff --git a/include/linux/trace_events.h b/include/linux/trace_events.h index 0a2b8229b999..ce6ba759a937 100644 --- a/include/linux/trace_events.h +++ b/include/linux/trace_events.h @@ -325,6 +325,7 @@ enum { TRACE_EVENT_FL_UPROBE_BIT, TRACE_EVENT_FL_EPROBE_BIT, TRACE_EVENT_FL_FPROBE_BIT, + TRACE_EVENT_FL_WPROBE_BIT, TRACE_EVENT_FL_CUSTOM_BIT, TRACE_EVENT_FL_TEST_STR_BIT, }; @@ -355,6 +356,7 @@ enum { TRACE_EVENT_FL_UPROBE =3D (1 << TRACE_EVENT_FL_UPROBE_BIT), TRACE_EVENT_FL_EPROBE =3D (1 << TRACE_EVENT_FL_EPROBE_BIT), TRACE_EVENT_FL_FPROBE =3D (1 << TRACE_EVENT_FL_FPROBE_BIT), + TRACE_EVENT_FL_WPROBE =3D (1 << TRACE_EVENT_FL_WPROBE_BIT), TRACE_EVENT_FL_CUSTOM =3D (1 << TRACE_EVENT_FL_CUSTOM_BIT), TRACE_EVENT_FL_TEST_STR =3D (1 << TRACE_EVENT_FL_TEST_STR_BIT), }; diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig index bfa2ec46e075..e09494c09cd5 100644 --- a/kernel/trace/Kconfig +++ b/kernel/trace/Kconfig @@ -847,6 +847,19 @@ config EPROBE_EVENTS convert the type of an event field. For example, turn an address into a string. =20 +config WPROBE_EVENTS + bool "Enable wprobe-based dynamic events" + depends on TRACING + depends on HAVE_HW_BREAKPOINT + select PROBE_EVENTS + select DYNAMIC_EVENTS + help + This allows the user to add watchpoint tracing events based on + hardware breakpoints on the fly via the ftrace interface. + + Those events can be inserted wherever hardware breakpoints can be + set, and record accessed memory address and values. + config BPF_EVENTS depends on BPF_SYSCALL depends on (KPROBE_EVENTS || UPROBE_EVENTS) && PERF_EVENTS diff --git a/kernel/trace/Makefile b/kernel/trace/Makefile index fc5dcc888e13..02a2ce0e6099 100644 --- a/kernel/trace/Makefile +++ b/kernel/trace/Makefile @@ -123,6 +123,7 @@ obj-$(CONFIG_FTRACE_RECORD_RECURSION) +=3D trace_recurs= ion_record.o obj-$(CONFIG_FPROBE) +=3D fprobe.o obj-$(CONFIG_RETHOOK) +=3D rethook.o obj-$(CONFIG_FPROBE_EVENTS) +=3D trace_fprobe.o +obj-$(CONFIG_WPROBE_EVENTS) +=3D trace_wprobe.o =20 obj-$(CONFIG_TRACEPOINT_BENCHMARK) +=3D trace_benchmark.o obj-$(CONFIG_RV) +=3D rv/ diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 396d59202438..261d0120e0f3 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -5580,8 +5580,12 @@ static const char readme_msg[] =3D " uprobe_events\t\t- Create/append/remove/show the userspace dynamic eve= nts\n" "\t\t\t Write into this file to define/undefine new trace events.\n" #endif +#ifdef CONFIG_WPROBE_EVENTS + " wprobe_events\t\t- Create/append/remove/show the hardware breakpoint d= ynamic events\n" + "\t\t\t Write into this file to define/undefine new trace events.\n" +#endif #if defined(CONFIG_KPROBE_EVENTS) || defined(CONFIG_UPROBE_EVENTS) || \ - defined(CONFIG_FPROBE_EVENTS) + defined(CONFIG_FPROBE_EVENTS) || defined(CONFIG_WPROBE_EVENTS) "\t accepts: event-definitions (one definition per line)\n" #if defined(CONFIG_KPROBE_EVENTS) || defined(CONFIG_UPROBE_EVENTS) "\t Format: p[:[/][]] []\n" @@ -5591,6 +5595,9 @@ static const char readme_msg[] =3D "\t f[:[/][]] [%return] []\n" "\t t[:[/][]] []\n" #endif +#ifdef CONFIG_WPROBE_EVENTS + "\t w[:[/][]] [r|w|rw]@[:]\n" +#endif #ifdef CONFIG_HIST_TRIGGERS "\t s:[synthetic/] []\n" #endif diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index 69e7defba6c6..7750dca87c44 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -176,6 +176,11 @@ struct fexit_trace_entry_head { unsigned long ret_ip; }; =20 +struct wprobe_trace_entry_head { + struct trace_entry ent; + unsigned long ip; +}; + #define TRACE_BUF_SIZE 1024 =20 struct trace_array; diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c index 2f571083ce9e..617c196ed730 100644 --- a/kernel/trace/trace_probe.c +++ b/kernel/trace/trace_probe.c @@ -968,6 +968,24 @@ static int parse_probe_vars(char *orig_arg, const stru= ct fetch_type *t, goto inval; } =20 + /* wprobe only support "$addr" and "$value" variable */ + if (ctx->flags & TPARG_FL_WPROBE) { + if (!strcmp(arg, "addr")) { + code->op =3D FETCH_OP_BADDR; + return 0; + } + if (!strcmp(arg, "value")) { + code->op =3D FETCH_OP_BADDR; + code++; + code->op =3D FETCH_OP_DEREF; + code->offset =3D 0; + *pcode =3D code; + return 0; + } + err =3D TP_ERR_BAD_VAR; + goto inval; + } + if (str_has_prefix(arg, "retval")) { if (!(ctx->flags & TPARG_FL_RETURN)) { err =3D TP_ERR_RETVAL_ON_PROBE; @@ -1097,8 +1115,9 @@ parse_probe_arg(char *arg, const struct fetch_type *t= ype, ret =3D parse_probe_vars(arg, type, pcode, end, ctx); break; =20 +#ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API case '%': /* named register */ - if (ctx->flags & (TPARG_FL_TEVENT | TPARG_FL_FPROBE)) { + if (ctx->flags & (TPARG_FL_TEVENT | TPARG_FL_FPROBE | TPARG_FL_WPROBE)) { /* eprobe and fprobe do not handle registers */ trace_probe_log_err(ctx->offset, BAD_VAR); break; @@ -1111,6 +1130,7 @@ parse_probe_arg(char *arg, const struct fetch_type *t= ype, } else trace_probe_log_err(ctx->offset, BAD_REG_NAME); break; +#endif =20 case '@': /* memory, file-offset or symbol */ if (isdigit(arg[1])) { diff --git a/kernel/trace/trace_probe.h b/kernel/trace/trace_probe.h index 9fc56c937130..591adc9bb1e9 100644 --- a/kernel/trace/trace_probe.h +++ b/kernel/trace/trace_probe.h @@ -89,6 +89,7 @@ enum fetch_op { FETCH_OP_STACK, /* Stack : .param =3D index */ FETCH_OP_STACKP, /* Stack pointer */ FETCH_OP_RETVAL, /* Return value */ + FETCH_OP_BADDR, /* Break address */ FETCH_OP_IMM, /* Immediate : .immediate */ FETCH_OP_COMM, /* Current comm */ FETCH_OP_ARG, /* Function argument : .param */ @@ -401,6 +402,7 @@ static inline int traceprobe_get_entry_data_size(struct= trace_probe *tp) #define TPARG_FL_USER BIT(4) #define TPARG_FL_FPROBE BIT(5) #define TPARG_FL_TPOINT BIT(6) +#define TPARG_FL_WPROBE BIT(7) #define TPARG_FL_LOC_MASK GENMASK(4, 0) =20 static inline bool tparg_is_function_entry(unsigned int flags) @@ -561,7 +563,11 @@ extern int traceprobe_define_arg_fields(struct trace_e= vent_call *event_call, C(BAD_TYPE4STR, "This type does not fit for string."),\ C(NEED_STRING_TYPE, "$comm and immediate-string only accepts string type"= ),\ C(TOO_MANY_ARGS, "Too many arguments are specified"), \ - C(TOO_MANY_EARGS, "Too many entry arguments specified"), + C(TOO_MANY_EARGS, "Too many entry arguments specified"), \ + C(BAD_ACCESS_FMT, "Access memory address requires @"), \ + C(BAD_ACCESS_TYPE, "Bad memory access type"), \ + C(BAD_ACCESS_LEN, "This memory access length is not supported"), \ + C(BAD_ACCESS_ADDR, "Invalid access memory address"), =20 #undef C #define C(a, b) TP_ERR_##a diff --git a/kernel/trace/trace_wprobe.c b/kernel/trace/trace_wprobe.c new file mode 100644 index 000000000000..4b00a8e917c1 --- /dev/null +++ b/kernel/trace/trace_wprobe.c @@ -0,0 +1,685 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Hardware-breakpoint-based tracing events + * + * Copyright (C) 2023, Masami Hiramatsu + */ +#define pr_fmt(fmt) "trace_wprobe: " fmt + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include + +#include "trace_dynevent.h" +#include "trace_probe.h" +#include "trace_probe_kernel.h" +#include "trace_probe_tmpl.h" + +#define WPROBE_EVENT_SYSTEM "wprobes" + +static int trace_wprobe_create(const char *raw_command); +static int trace_wprobe_show(struct seq_file *m, struct dyn_event *ev); +static int trace_wprobe_release(struct dyn_event *ev); +static bool trace_wprobe_is_busy(struct dyn_event *ev); +static bool trace_wprobe_match(const char *system, const char *event, + int argc, const char **argv, struct dyn_event *ev); + +static struct dyn_event_operations trace_wprobe_ops =3D { + .create =3D trace_wprobe_create, + .show =3D trace_wprobe_show, + .is_busy =3D trace_wprobe_is_busy, + .free =3D trace_wprobe_release, + .match =3D trace_wprobe_match, +}; + +struct trace_wprobe { + struct dyn_event devent; + struct perf_event * __percpu *bp_event; + unsigned long addr; + int len; + int type; + const char *symbol; + struct trace_probe tp; +}; + +static bool is_trace_wprobe(struct dyn_event *ev) +{ + return ev->ops =3D=3D &trace_wprobe_ops; +} + +static struct trace_wprobe *to_trace_wprobe(struct dyn_event *ev) +{ + return container_of(ev, struct trace_wprobe, devent); +} + +#define for_each_trace_wprobe(pos, dpos) \ + for_each_dyn_event(dpos) \ + if (is_trace_wprobe(dpos) && (pos =3D to_trace_wprobe(dpos))) + +static bool trace_wprobe_is_busy(struct dyn_event *ev) +{ + struct trace_wprobe *tw =3D to_trace_wprobe(ev); + + return trace_probe_is_enabled(&tw->tp); +} + +static bool trace_wprobe_match(const char *system, const char *event, + int argc, const char **argv, struct dyn_event *ev) +{ + struct trace_wprobe *tw =3D to_trace_wprobe(ev); + + if (event[0] !=3D '\0' && strcmp(trace_probe_name(&tw->tp), event)) + return false; + + if (system && strcmp(trace_probe_group_name(&tw->tp), system)) + return false; + + /* TODO: match arguments */ + return true; +} + +/* + * Note that we don't verify the fetch_insn code, since it does not come + * from user space. + */ +static int +process_fetch_insn(struct fetch_insn *code, void *rec, void *edata, + void *dest, void *base) +{ + void *baddr =3D rec; + unsigned long val; + int ret; + +retry: + /* 1st stage: get value from context */ + switch (code->op) { + case FETCH_OP_BADDR: + val =3D (unsigned long)baddr; + break; + case FETCH_NOP_SYMBOL: /* Ignore a place holder */ + code++; + goto retry; + default: + ret =3D process_common_fetch_insn(code, &val); + if (ret < 0) + return ret; + } + code++; + + return process_fetch_insn_bottom(code, val, dest, base); +} +NOKPROBE_SYMBOL(process_fetch_insn) + +static void wprobe_trace_handler(struct trace_wprobe *tw, + struct perf_sample_data *data, + struct pt_regs *regs, + struct trace_event_file *trace_file) +{ + struct wprobe_trace_entry_head *entry; + struct trace_event_call *call =3D trace_probe_event_call(&tw->tp); + struct trace_event_buffer fbuffer; + int dsize; + + if (WARN_ON_ONCE(call !=3D trace_file->event_call)) + return; + + if (trace_trigger_soft_disabled(trace_file)) + return; + + dsize =3D __get_data_size(&tw->tp, (void *)tw->addr, NULL); + + entry =3D trace_event_buffer_reserve(&fbuffer, trace_file, + sizeof(*entry) + tw->tp.size + dsize); + if (!entry) + return; + + entry->ip =3D instruction_pointer(regs); + store_trace_args(&entry[1], &tw->tp, (void *)tw->addr, NULL, sizeof(*entr= y), dsize); + + fbuffer.regs =3D regs; + trace_event_buffer_commit(&fbuffer); +} + +static void wprobe_perf_handler(struct perf_event *bp, + struct perf_sample_data *data, + struct pt_regs *regs) +{ + struct trace_wprobe *tw =3D bp->overflow_handler_context; + struct event_file_link *link; + + trace_probe_for_each_link_rcu(link, &tw->tp) + wprobe_trace_handler(tw, data, regs, link->file); +} + +static int __register_trace_wprobe(struct trace_wprobe *tw) +{ + struct perf_event_attr attr; + + if (tw->bp_event) + return -EINVAL; + + hw_breakpoint_init(&attr); + attr.bp_addr =3D tw->addr; + attr.bp_len =3D tw->len; + attr.bp_type =3D tw->type; + + tw->bp_event =3D register_wide_hw_breakpoint(&attr, wprobe_perf_handler, = tw); + if (IS_ERR((void * __force)tw->bp_event)) { + int ret =3D PTR_ERR((void * __force)tw->bp_event); + + tw->bp_event =3D NULL; + return ret; + } + + return 0; +} + +static void __unregister_trace_wprobe(struct trace_wprobe *tw) +{ + if (tw->bp_event) { + unregister_wide_hw_breakpoint(tw->bp_event); + tw->bp_event =3D NULL; + } +} + +static void free_trace_wprobe(struct trace_wprobe *tw) +{ + if (tw) { + trace_probe_cleanup(&tw->tp); + kfree(tw->symbol); + kfree(tw); + } +} +DEFINE_FREE(free_trace_wprobe, struct trace_wprobe *, if (!IS_ERR_OR_NULL(= _T)) free_trace_wprobe(_T)); + +static struct trace_wprobe *alloc_trace_wprobe(const char *group, + const char *event, + const char *symbol, + unsigned long addr, + int len, int type, int nargs) +{ + struct trace_wprobe *tw __free(free_trace_wprobe) =3D NULL; + int ret; + + tw =3D kzalloc(struct_size(tw, tp.args, nargs), GFP_KERNEL); + if (!tw) + return ERR_PTR(-ENOMEM); + + if (symbol) { + tw->symbol =3D kstrdup(symbol, GFP_KERNEL); + if (!tw->symbol) + return ERR_PTR(-ENOMEM); + } + tw->addr =3D addr; + tw->len =3D len; + tw->type =3D type; + + ret =3D trace_probe_init(&tw->tp, event, group, false, nargs); + if (ret < 0) + return ERR_PTR(ret); + + dyn_event_init(&tw->devent, &trace_wprobe_ops); + return_ptr(tw); +} + +static struct trace_wprobe *find_trace_wprobe(const char *event, + const char *group) +{ + struct dyn_event *pos; + struct trace_wprobe *tw; + + for_each_trace_wprobe(tw, pos) + if (strcmp(trace_probe_name(&tw->tp), event) =3D=3D 0 && + strcmp(trace_probe_group_name(&tw->tp), group) =3D=3D 0) + return tw; + return NULL; +} + +static enum print_line_t +print_wprobe_event(struct trace_iterator *iter, int flags, + struct trace_event *event) +{ + struct wprobe_trace_entry_head *field; + struct trace_seq *s =3D &iter->seq; + struct trace_probe *tp; + + field =3D (struct wprobe_trace_entry_head *)iter->ent; + tp =3D trace_probe_primary_from_call( + container_of(event, struct trace_event_call, event)); + if (WARN_ON_ONCE(!tp)) + goto out; + + trace_seq_printf(s, "%s: (", trace_probe_name(tp)); + + if (!seq_print_ip_sym(s, field->ip, flags | TRACE_ITER_SYM_OFFSET)) + goto out; + + trace_seq_putc(s, ')'); + + if (trace_probe_print_args(s, tp->args, tp->nr_args, + (u8 *)&field[1], field) < 0) + goto out; + + trace_seq_putc(s, '\n'); +out: + return trace_handle_return(s); +} + +static int wprobe_event_define_fields(struct trace_event_call *event_call) +{ + int ret; + struct wprobe_trace_entry_head field; + struct trace_probe *tp; + + tp =3D trace_probe_primary_from_call(event_call); + if (WARN_ON_ONCE(!tp)) + return -ENOENT; + + DEFINE_FIELD(unsigned long, ip, FIELD_STRING_IP, 0); + + return traceprobe_define_arg_fields(event_call, sizeof(field), tp); +} + +static struct trace_event_functions wprobe_funcs =3D { + .trace =3D print_wprobe_event +}; + +static struct trace_event_fields wprobe_fields_array[] =3D { + { .type =3D TRACE_FUNCTION_TYPE, + .define_fields =3D wprobe_event_define_fields }, + {} +}; + +static int wprobe_register(struct trace_event_call *event, + enum trace_reg type, void *data); + +static inline void init_trace_event_call(struct trace_wprobe *tw) +{ + struct trace_event_call *call =3D trace_probe_event_call(&tw->tp); + + call->event.funcs =3D &wprobe_funcs; + call->class->fields_array =3D wprobe_fields_array; + call->flags =3D TRACE_EVENT_FL_WPROBE; + call->class->reg =3D wprobe_register; +} + +static int register_wprobe_event(struct trace_wprobe *tw) +{ + init_trace_event_call(tw); + return trace_probe_register_event_call(&tw->tp); +} + +static int register_trace_wprobe_event(struct trace_wprobe *tw) +{ + struct trace_wprobe *old_tb; + int ret; + + guard(mutex)(&event_mutex); + + old_tb =3D find_trace_wprobe(trace_probe_name(&tw->tp), + trace_probe_group_name(&tw->tp)); + if (old_tb) + return -EBUSY; + + ret =3D register_wprobe_event(tw); + if (ret) + return ret; + + dyn_event_add(&tw->devent, trace_probe_event_call(&tw->tp)); + return 0; +} +static int unregister_wprobe_event(struct trace_wprobe *tw) +{ + return trace_probe_unregister_event_call(&tw->tp); +} + +static int unregister_trace_wprobe(struct trace_wprobe *tw) +{ + if (trace_probe_has_sibling(&tw->tp)) + goto unreg; + + if (trace_probe_is_enabled(&tw->tp)) + return -EBUSY; + + if (trace_event_dyn_busy(trace_probe_event_call(&tw->tp))) + return -EBUSY; + + if (unregister_wprobe_event(tw)) + return -EBUSY; + +unreg: + __unregister_trace_wprobe(tw); + dyn_event_remove(&tw->devent); + trace_probe_unlink(&tw->tp); + + return 0; +} + +static int enable_trace_wprobe(struct trace_event_call *call, + struct trace_event_file *file) +{ + struct trace_probe *tp; + struct trace_wprobe *tw; + bool enabled; + int ret =3D 0; + + tp =3D trace_probe_primary_from_call(call); + if (WARN_ON_ONCE(!tp)) + return -ENODEV; + enabled =3D trace_probe_is_enabled(tp); + + if (file) { + ret =3D trace_probe_add_file(tp, file); + if (ret) + return ret; + } else { + trace_probe_set_flag(tp, TP_FLAG_PROFILE); + } + + if (!enabled) { + list_for_each_entry(tw, trace_probe_probe_list(tp), tp.list) { + ret =3D __register_trace_wprobe(tw); + if (ret < 0) { + /* TODO: rollback */ + return ret; + } + } + } + + return 0; +} + +static int disable_trace_wprobe(struct trace_event_call *call, + struct trace_event_file *file) +{ + struct trace_wprobe *tw; + struct trace_probe *tp; + + tp =3D trace_probe_primary_from_call(call); + if (WARN_ON_ONCE(!tp)) + return -ENODEV; + + if (file) { + if (!trace_probe_get_file_link(tp, file)) + return -ENOENT; + if (!trace_probe_has_single_file(tp)) + goto out; + trace_probe_clear_flag(tp, TP_FLAG_TRACE); + } else { + trace_probe_clear_flag(tp, TP_FLAG_PROFILE); + } + + if (!trace_probe_is_enabled(tp)) { + list_for_each_entry(tw, trace_probe_probe_list(tp), tp.list) { + __unregister_trace_wprobe(tw); + } + } + +out: + if (file) + trace_probe_remove_file(tp, file); + + return 0; +} + +static int wprobe_register(struct trace_event_call *event, + enum trace_reg type, void *data) +{ + struct trace_event_file *file =3D data; + + switch (type) { + case TRACE_REG_REGISTER: + return enable_trace_wprobe(event, file); + case TRACE_REG_UNREGISTER: + return disable_trace_wprobe(event, file); + +#ifdef CONFIG_PERF_EVENTS + case TRACE_REG_PERF_REGISTER: + return enable_trace_wprobe(event, NULL); + case TRACE_REG_PERF_UNREGISTER: + return disable_trace_wprobe(event, NULL); + case TRACE_REG_PERF_OPEN: + case TRACE_REG_PERF_CLOSE: + case TRACE_REG_PERF_ADD: + case TRACE_REG_PERF_DEL: + return 0; +#endif + } + return 0; +} + +static int parse_address_spec(const char *spec, unsigned long *addr, int *= type, + int *len, char **symbol) +{ + char *_spec __free(kfree) =3D NULL; + int _len =3D HW_BREAKPOINT_LEN_4; + int _type =3D HW_BREAKPOINT_RW; + unsigned long _addr =3D 0; + char *at, *col; + + _spec =3D kstrdup(spec, GFP_KERNEL); + if (!_spec) + return -ENOMEM; + + at =3D strchr(_spec, '@'); + col =3D strchr(_spec, ':'); + + if (!at) { + trace_probe_log_err(0, BAD_ACCESS_FMT); + return -EINVAL; + } + + if (at !=3D _spec) { + *at =3D '\0'; + + if (strcmp(_spec, "r") =3D=3D 0) + _type =3D HW_BREAKPOINT_R; + else if (strcmp(_spec, "w") =3D=3D 0) + _type =3D HW_BREAKPOINT_W; + else if (strcmp(_spec, "rw") =3D=3D 0) + _type =3D HW_BREAKPOINT_RW; + else { + trace_probe_log_err(0, BAD_ACCESS_TYPE); + return -EINVAL; + } + } + + if (col) { + *col =3D '\0'; + if (kstrtoint(col + 1, 0, &_len)) { + trace_probe_log_err(col + 1 - _spec, BAD_ACCESS_LEN); + return -EINVAL; + } + + switch (_len) { + case 1: + _len =3D HW_BREAKPOINT_LEN_1; + break; + case 2: + _len =3D HW_BREAKPOINT_LEN_2; + break; + case 4: + _len =3D HW_BREAKPOINT_LEN_4; + break; + case 8: + _len =3D HW_BREAKPOINT_LEN_8; + break; + default: + trace_probe_log_err(col + 1 - _spec, BAD_ACCESS_LEN); + return -EINVAL; + } + } + + if (kstrtoul(at + 1, 0, &_addr) !=3D 0) { + char *off_str =3D strpbrk(at + 1, "+-"); + int offset =3D 0; + + if (off_str) { + if (kstrtoint(off_str, 0, &offset) !=3D 0) { + trace_probe_log_err(off_str - _spec, BAD_PROBE_ADDR); + return -EINVAL; + } + *off_str =3D '\0'; + } + _addr =3D kallsyms_lookup_name(at + 1); + if (!_addr) { + trace_probe_log_err(at + 1 - _spec, BAD_ACCESS_ADDR); + return -ENOENT; + } + _addr +=3D offset; + *symbol =3D kstrdup(at + 1, GFP_KERNEL); + if (!*symbol) + return -ENOMEM; + } + + *addr =3D _addr; + *type =3D _type; + *len =3D _len; + return 0; +} + +static int __trace_wprobe_create(int argc, const char *argv[]) +{ + /* + * Argument syntax: + * b[:[GRP/][EVENT]] SPEC + * + * SPEC: + * [r|w|rw]@[ADDR|SYMBOL[+OFFS]][:LEN] + */ + struct traceprobe_parse_context *ctx __free(traceprobe_parse_context) =3D= NULL; + struct trace_wprobe *tw __free(free_trace_wprobe) =3D NULL; + const char *event =3D NULL, *group =3D WPROBE_EVENT_SYSTEM; + const char *tplog __free(trace_probe_log_clear) =3D NULL; + char *symbol =3D NULL; + unsigned long addr; + int len, type, i; + int ret =3D 0; + + if (argv[0][0] !=3D 'w') + return -ECANCELED; + + if (argc < 2) + return -EINVAL; + + tplog =3D trace_probe_log_init("wprobe", argc, argv); + + if (argv[0][1] !=3D '\0') { + if (argv[0][1] !=3D ':') { + trace_probe_log_set_index(0); + trace_probe_log_err(1, BAD_MAXACT_TYPE); + /* Invalid format */ + return -EINVAL; + } + event =3D &argv[0][2]; + } + + trace_probe_log_set_index(1); + ret =3D parse_address_spec(argv[1], &addr, &type, &len, &symbol); + if (ret < 0) + return ret; + + if (!event) + event =3D symbol ? symbol : "wprobe"; + + argc -=3D 2; argv +=3D 2; + tw =3D alloc_trace_wprobe(group, event, symbol, addr, len, type, argc); + if (IS_ERR(tw)) + return PTR_ERR(tw); + + ctx =3D kzalloc(sizeof(*ctx), GFP_KERNEL); + if (!ctx) + return -ENOMEM; + + ctx->flags =3D TPARG_FL_KERNEL | TPARG_FL_WPROBE; + + /* parse arguments */ + for (i =3D 0; i < argc; i++) { + trace_probe_log_set_index(i + 2); + ctx->offset =3D 0; + ret =3D traceprobe_parse_probe_arg(&tw->tp, i, argv[i], ctx); + if (ret) + return ret; /* This can be -ENOMEM */ + } + + ret =3D traceprobe_set_print_fmt(&tw->tp, PROBE_PRINT_NORMAL); + if (ret < 0) + return ret; + + ret =3D register_trace_wprobe_event(tw); + if (!ret) + tw =3D NULL; /* To avoid free */ + + return ret; +} + +static int trace_wprobe_create(const char *raw_command) +{ + return trace_probe_create(raw_command, __trace_wprobe_create); +} + +static int trace_wprobe_release(struct dyn_event *ev) +{ + struct trace_wprobe *tw =3D to_trace_wprobe(ev); + int ret =3D unregister_trace_wprobe(tw); + + if (!ret) + free_trace_wprobe(tw); + return ret; +} + +static int trace_wprobe_show(struct seq_file *m, struct dyn_event *ev) +{ + struct trace_wprobe *tw =3D to_trace_wprobe(ev); + int i; + + seq_printf(m, "w:%s/%s", trace_probe_group_name(&tw->tp), + trace_probe_name(&tw->tp)); + + char type_char; + + if (tw->type =3D=3D HW_BREAKPOINT_R) + type_char =3D 'r'; + else if (tw->type =3D=3D HW_BREAKPOINT_W) + type_char =3D 'w'; + else + type_char =3D 'x'; /* Should be rw */ + + int len; + + if (tw->len =3D=3D HW_BREAKPOINT_LEN_1) + len =3D 1; + else if (tw->len =3D=3D HW_BREAKPOINT_LEN_2) + len =3D 2; + else if (tw->len =3D=3D HW_BREAKPOINT_LEN_4) + len =3D 4; + else + len =3D 8; + + if (tw->symbol) + seq_printf(m, " %c@%s:%d", type_char, tw->symbol, len); + else + seq_printf(m, " %c@0x%lx:%d", type_char, tw->addr, len); + + for (i =3D 0; i < tw->tp.nr_args; i++) + seq_printf(m, " %s=3D%s", tw->tp.args[i].name, tw->tp.args[i].comm); + seq_putc(m, '\n'); + + return 0; +} + +static __init int init_wprobe_trace(void) +{ + return dyn_event_register(&trace_wprobe_ops); +} +fs_initcall(init_wprobe_trace); + From nobody Sat Feb 7 15:22:00 2026 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 504072459CF; Wed, 28 Jan 2026 14:09:27 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; 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Peter Anvin" , Alexander Shishkin , Ian Rogers , linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-perf-users@vger.kernel.org Subject: [PATCH v6 02/11] x86: hw_breakpoint: Add a kconfig to clarify when a breakpoint fires Date: Wed, 28 Jan 2026 23:09:21 +0900 Message-ID: <176960936178.182525.3819325751118979093.stgit@devnote2> X-Mailer: git-send-email 2.43.0 In-Reply-To: <176960933881.182525.11984731584313026309.stgit@devnote2> References: <176960933881.182525.11984731584313026309.stgit@devnote2> User-Agent: StGit/0.19 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable From: Masami Hiramatsu (Google) Add CONFIG_HAVE_POST_BREAKPOINT_HOOK which indicates the hw_breakpoint on that architecture fires after the target memory has been modified. This is currently x86 only behavior. Signed-off-by: Masami Hiramatsu (Google) --- arch/Kconfig | 10 ++++++++++ arch/x86/Kconfig | 1 + kernel/trace/Kconfig | 1 + 3 files changed, 12 insertions(+) diff --git a/arch/Kconfig b/arch/Kconfig index 31220f512b16..64adda21c5f6 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -453,6 +453,16 @@ config HAVE_MIXED_BREAKPOINTS_REGS Select this option if your arch implements breakpoints under the latter fashion. =20 +config HAVE_POST_BREAKPOINT_HOOK + bool + depends on HAVE_HW_BREAKPOINT + help + Depending on the arch implementation of hardware breakpoints, + some of them provide breakpoint hook after the target memory + is modified. + Select this option if your arch implements breakpoints overflow + handler hooks after the target memory is modified. + config HAVE_USER_RETURN_NOTIFIER bool =20 diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 80527299f859..755fd3bd4334 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -246,6 +246,7 @@ config X86 select HAVE_FUNCTION_TRACER select HAVE_GCC_PLUGINS select HAVE_HW_BREAKPOINT + select HAVE_POST_BREAKPOINT_HOOK select HAVE_IOREMAP_PROT select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64 select HAVE_IRQ_TIME_ACCOUNTING diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig index e09494c09cd5..087a27b56eb1 100644 --- a/kernel/trace/Kconfig +++ b/kernel/trace/Kconfig @@ -851,6 +851,7 @@ config WPROBE_EVENTS bool "Enable wprobe-based dynamic events" depends on TRACING depends on HAVE_HW_BREAKPOINT + depends on HAVE_POST_BREAKPOINT_HOOK select PROBE_EVENTS select DYNAMIC_EVENTS help From nobody Sat Feb 7 15:22:00 2026 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8685024A078; Wed, 28 Jan 2026 14:09:38 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769609378; cv=none; b=cHuyA7zSFzXlaD3bRyLZKAYgTNzyEjn0ZPdnxeec2H0SdE1ou1Bn/QkluBrWPX8CMGrwW5idpSWzH/eBe5QIXWzX0+TcUHPPsvmPf2+vqbhLAM14IhXYzR7ip5nzeRTkZ75yxeMmrw7xMdOK8k/iMYZF9sLiXrhTmN1ja2BsVUY= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769609378; c=relaxed/simple; bh=XkgXf+BmWb1gm42X0hFSsPY2QiN+40F9WNZpKmrmhe0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=b1rMGzQgqTRC3CghKVLQ4nM2aNpzWyCApImOzzWYDqn4DgbpOqw8VUaHGCWCBl4y/RkynQxLDzQPAVwdLGfWAGD9/90/uLMRVgNz4gjs4gGFXBQG+5Ji+HVUiL4ORKHFuk+5zVx0d9jY/JvVtty5mxN/ZwhERGZN6XtLLdJebCg= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Aw7nGGC4; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Aw7nGGC4" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E1704C4CEF1; Wed, 28 Jan 2026 14:09:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1769609378; bh=XkgXf+BmWb1gm42X0hFSsPY2QiN+40F9WNZpKmrmhe0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Aw7nGGC4UNYoZWyQ4rHJ0MXmatEaqC7GyfGGFpfKE8wLg76B9QGK+vDmcJBpbKZ2x inKIHprlRK7XE3OeilW2BDXJN4d98FU+5BhvZRZUUt46YMV2pDBGOHiXcxcwvGfKnl dAEEjCSEIMXI1Wjj38ROLLJx9ML1pTZWTULYiyB7bZhdP0W8l6tlateYssFXE3Wm2e KaSvF9G9MfBETwXddybdfQvkvPshKMZmWkGKjuKCr7ZC6DiOX7Z1Kp/Xvdr4Oy3KU7 FcLtj6vw6k4UUrDiQurFhA033BztFgWAMcyjN5S/qrXvzXX7WTyBfqPLo4MM6M/Uvh DXyqUM0YrQyDw== From: "Masami Hiramatsu (Google)" To: Steven Rostedt , Peter Zijlstra , Ingo Molnar , x86@kernel.org Cc: Jinchao Wang , Mathieu Desnoyers , Masami Hiramatsu , Thomas Gleixner , Borislav Petkov , Dave Hansen , "H . Peter Anvin" , Alexander Shishkin , Ian Rogers , linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-perf-users@vger.kernel.org Subject: [PATCH v6 03/11] selftests: tracing: Add a basic testcase for wprobe Date: Wed, 28 Jan 2026 23:09:32 +0900 Message-ID: <176960937225.182525.10205736065393489911.stgit@devnote2> X-Mailer: git-send-email 2.43.0 In-Reply-To: <176960933881.182525.11984731584313026309.stgit@devnote2> References: <176960933881.182525.11984731584313026309.stgit@devnote2> User-Agent: StGit/0.19 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable From: Masami Hiramatsu (Google) Add 'add_remove_wprobe.tc' testcase for testing wprobe event that tests adding and removing operations of the wprobe event. Link: https://lore.kernel.org/all/175859026716.374439.14852239332989324292.= stgit@devnote2/ Signed-off-by: Masami Hiramatsu (Google) --- tools/testing/selftests/ftrace/config | 1=20 .../ftrace/test.d/dynevent/add_remove_wprobe.tc | 68 ++++++++++++++++= ++++ 2 files changed, 69 insertions(+) create mode 100644 tools/testing/selftests/ftrace/test.d/dynevent/add_remo= ve_wprobe.tc diff --git a/tools/testing/selftests/ftrace/config b/tools/testing/selftest= s/ftrace/config index 544de0db5f58..d2f503722020 100644 --- a/tools/testing/selftests/ftrace/config +++ b/tools/testing/selftests/ftrace/config @@ -27,3 +27,4 @@ CONFIG_STACK_TRACER=3Dy CONFIG_TRACER_SNAPSHOT=3Dy CONFIG_UPROBES=3Dy CONFIG_UPROBE_EVENTS=3Dy +CONFIG_WPROBE_EVENTS=3Dy diff --git a/tools/testing/selftests/ftrace/test.d/dynevent/add_remove_wpro= be.tc b/tools/testing/selftests/ftrace/test.d/dynevent/add_remove_wprobe.tc new file mode 100644 index 000000000000..20774c7f69f8 --- /dev/null +++ b/tools/testing/selftests/ftrace/test.d/dynevent/add_remove_wprobe.tc @@ -0,0 +1,68 @@ +#!/bin/sh +# SPDX-License-Identifier: GPL-2.0 +# description: Generic dynamic event - add/remove wprobe events +# requires: dynamic_events "w[:[/][]] [r|w|rw]@[:= ]":README + +echo 0 > events/enable +echo > dynamic_events + +# Use jiffies as a variable that is frequently written to. +TARGET=3Djiffies + +echo "w:my_wprobe w@$TARGET" >> dynamic_events + +grep -q my_wprobe dynamic_events +if [ $? -ne 0 ]; then + echo "Failed to create wprobe event" + exit_fail +fi + +test -d events/wprobes/my_wprobe +if [ $? -ne 0 ]; then + echo "Failed to create wprobe event directory" + exit_fail +fi + +echo 1 > events/wprobes/my_wprobe/enable + +# Check if the event is enabled +cat events/wprobes/my_wprobe/enable | grep -q 1 +if [ $? -ne 0 ]; then + echo "Failed to enable wprobe event" + exit_fail +fi + +# Let some time pass to trigger the breakpoint +sleep 1 + +# Check if we got any trace output +if !grep -q my_wprobe trace; then + echo "wprobe event was not triggered" +fi + +echo 0 > events/wprobes/my_wprobe/enable + +# Check if the event is disabled +cat events/wprobes/my_wprobe/enable | grep -q 0 +if [ $? -ne 0 ]; then + echo "Failed to disable wprobe event" + exit_fail +fi + +echo "-:my_wprobe" >> dynamic_events + +! grep -q my_wprobe dynamic_events +if [ $? -ne 0 ]; then + echo "Failed to remove wprobe event" + exit_fail +fi + +! test -d events/wprobes/my_wprobe +if [ $? -ne 0 ]; then + echo "Failed to remove wprobe event directory" + exit_fail +fi + +clear_trace + +exit 0 From nobody Sat Feb 7 15:22:00 2026 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4B8D5239E60; Wed, 28 Jan 2026 14:09:49 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769609389; cv=none; b=WFtJjjyFcK5CMY7WzI/iawyT6tFVBa4c3XP5TOt91EPSkvLojT1niqYfnVJmsPIClaMV6k3j1VisFqkpO0o/GgnfJM/mwf4ywbE2LVwwqJXSQMwMvI9gsgn+p9fHfAMgR4PWzoE6lxiY4Tv/vTJiqn5i1uNbtR8AkZ8iZunUi3A= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769609389; c=relaxed/simple; bh=RnKOHNBPmj3Cu03w5U04I8JGBqtXnIak2+AQjeku/RI=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=dVdqiErg5xaAdRMGq8lVXOEQ45yO//1lZr7FnaifF5ABDFQt6VhJbd85WbRgRjtNmPfwX75PMqI/nrb8oOhUaoDc0v3AKQg/fhcDGUQ7eCMq0iFaljc1HZsXiLOtkwIIfj3fNJ4vUMdHJq5UabdP1fOsqsMKexgMcuktk5uyMkA= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=UJZ/858X; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="UJZ/858X" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A2442C4CEF1; Wed, 28 Jan 2026 14:09:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1769609389; bh=RnKOHNBPmj3Cu03w5U04I8JGBqtXnIak2+AQjeku/RI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=UJZ/858XNjPXIQa1OYYs61qFzFkQfhz5tjfJSoLwHrv+Ln9To+fLU1LqRjSCIkSbz hAMeyTUjIQyxUskoAaoTTfZYEKFOTLbRACCYES3/DnlsRgHOr895wtErI/cZD5PbkL vbQrBwwMVtlXyvgoG1aJk+rqStVNU4lY4Tz1RL/UGwZVkmAyTMSY+KDxFqb6vuqxON RGeTg+ie/vuw5HfFjLH51854oYXFgaMNnP7k4Oj1BZTMyv8QA9nUdzfV+8ygt3i8yN 3pFKWSGBe4u/XuHInmOTbabuMuOWOBZumTvh45yeyIEGZsR7nyVTR0EKDIKzDoddNV Y2UyOKME1kD3A== From: "Masami Hiramatsu (Google)" To: Steven Rostedt , Peter Zijlstra , Ingo Molnar , x86@kernel.org Cc: Jinchao Wang , Mathieu Desnoyers , Masami Hiramatsu , Thomas Gleixner , Borislav Petkov , Dave Hansen , "H . Peter Anvin" , Alexander Shishkin , Ian Rogers , linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-perf-users@vger.kernel.org Subject: [PATCH v6 04/11] selftests: tracing: Add syntax testcase for wprobe Date: Wed, 28 Jan 2026 23:09:43 +0900 Message-ID: <176960938340.182525.7033743309632028932.stgit@devnote2> X-Mailer: git-send-email 2.43.0 In-Reply-To: <176960933881.182525.11984731584313026309.stgit@devnote2> References: <176960933881.182525.11984731584313026309.stgit@devnote2> User-Agent: StGit/0.19 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable From: Masami Hiramatsu (Google) Add "wprobe_syntax_errors.tc" testcase for testing syntax errors of the watch probe events. Link: https://lore.kernel.org/all/175859027842.374439.6402700780945714048.s= tgit@devnote2/ Signed-off-by: Masami Hiramatsu (Google) --- .../test.d/dynevent/wprobes_syntax_errors.tc | 20 ++++++++++++++++= ++++ 1 file changed, 20 insertions(+) create mode 100644 tools/testing/selftests/ftrace/test.d/dynevent/wprobes_= syntax_errors.tc diff --git a/tools/testing/selftests/ftrace/test.d/dynevent/wprobes_syntax_= errors.tc b/tools/testing/selftests/ftrace/test.d/dynevent/wprobes_syntax_e= rrors.tc new file mode 100644 index 000000000000..56ac579d60ae --- /dev/null +++ b/tools/testing/selftests/ftrace/test.d/dynevent/wprobes_syntax_errors.= tc @@ -0,0 +1,20 @@ +#!/bin/sh +# SPDX-License-Identifier: GPL-2.0 +# description: Watch probe event parser error log check +# requires: dynamic_events "w[:[/][]] [r|w|rw]@[:= ]":README + +check_error() { # command-with-error-pos-by-^ + ftrace_errlog_check 'wprobe' "$1" 'dynamic_events' +} + +check_error 'w ^symbol' # BAD_ACCESS_FMT +check_error 'w ^a@symbol' # BAD_ACCESS_TYPE +check_error 'w w@^symbol' # BAD_ACCESS_ADDR +check_error 'w w@jiffies^+offset' # BAD_ACCESS_ADDR +check_error 'w w@jiffies:^100' # BAD_ACCESS_LEN +check_error 'w w@jiffies ^$arg1' # BAD_VAR +check_error 'w w@jiffies ^$retval' # BAD_VAR +check_error 'w w@jiffies ^$stack' # BAD_VAR +check_error 'w w@jiffies ^%ax' # BAD_VAR + +exit 0 From nobody Sat Feb 7 15:22:00 2026 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8227A230BF6; Wed, 28 Jan 2026 14:10:00 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769609400; cv=none; b=IJhCKBB7mRJPNiBCvg20wXvuGVAcTiI3Ga25DY6QYG+RNvNd5x4VlK1XMXggJd72PJB3udTzR334H7aEbjNBHUqnAxJfA4vFzGlMNF6b2GMu3OJ24d6J9AM7L8n8CDpG6Ev6ADNc6sCxwhmHMP6E69xySZx3IeqjS/gyEY+WGj4= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769609400; c=relaxed/simple; bh=LillPVj+D01tzFsPNb4HRfbZ2n9V6Am4yy1/k9dGmvE=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=i+RtJ5XQ0wFKKAk9pZuLamSZ8cRuQGRRLmWWLHzwxp8Kehoh45ZTsWu5OrutihD9IPErLKRJd1Vtev3uHTKOOriZq3MP8+49ex1Qvm3yfeXC2c/pgduZMCiMVXw8K/crk6wCPxwFNI5idne73qFZyz24UJjwSf+SR+pBI1tzQV8= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=tml10nKW; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="tml10nKW" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9716AC4CEF1; Wed, 28 Jan 2026 14:09:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1769609400; bh=LillPVj+D01tzFsPNb4HRfbZ2n9V6Am4yy1/k9dGmvE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=tml10nKWeU387O4x0je4hPABZkRdkplgyN1Q3c91Wxvrcmt7nPNACwS3E52NCd902 knjrPfj6D2XlDCWPFXCM0LwsfTKiQX0xXJ1fZd/LjslhFFf2CeZ67IstbruwnIsDBW 4CFzvSy/3s9MuIeJW+VFqcJbMyvHIziirGYHDJzROFalqtPoJs7NT6HuFu3gLCVUyU hIM0T0nOC7xE3WvEUSGHzC+491E+oH0ujknEesFD9jAQJx5UoCubPZVYtolaZQX2wg SXdbMxBaq4PRFm3yqSs15OjKx7fBJ5Co9Hjy53VSLue2BoPeVDq64r5gJsBfFfIEZG +8DDLrBzNFVEA== From: "Masami Hiramatsu (Google)" To: Steven Rostedt , Peter Zijlstra , Ingo Molnar , x86@kernel.org Cc: Jinchao Wang , Mathieu Desnoyers , Masami Hiramatsu , Thomas Gleixner , Borislav Petkov , Dave Hansen , "H . Peter Anvin" , Alexander Shishkin , Ian Rogers , linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-perf-users@vger.kernel.org Subject: [PATCH v6 05/11] tracing: wprobe: Fix to use IS_ERR_PCPU() for per-cpu pointer Date: Wed, 28 Jan 2026 23:09:54 +0900 Message-ID: <176960939425.182525.15663394581634314970.stgit@devnote2> X-Mailer: git-send-email 2.43.0 In-Reply-To: <176960933881.182525.11984731584313026309.stgit@devnote2> References: <176960933881.182525.11984731584313026309.stgit@devnote2> User-Agent: StGit/0.19 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable From: Masami Hiramatsu (Google) Since wprobe uses IS_ERR() for per-cpu pointer, it failed to build. /tmp/next/build/kernel/trace/trace_wprobe.c: In function '__register_trace_= wprobe': /tmp/next/build/kernel/trace/trace_wprobe.c:176:20: error: cast to generic = address space pointer from disjoint '__seg_gs' address space pointer [-Werr= or] 176 | if (IS_ERR((void * __force)tw->bp_event)) { | ^ /tmp/next/build/kernel/trace/trace_wprobe.c:177:35: error: cast to generic = address space pointer from disjoint '__seg_gs' address space pointer [-Werr= or] 177 | int ret =3D PTR_ERR((void * __force)tw->bp_event); | ^ Use IS_ERR_PCPU() instead. Link: https://lore.kernel.org/all/175979899246.1800846.1725245135731182727.= stgit@devnote2/ Reported-by: Mark Brown Closes: https://lore.kernel.org/all/aN6fTmAjD7-SJsw2@sirena.org.uk/ Suggested-by: Linus Torvalds Signed-off-by: Masami Hiramatsu (Google) Reviewed-by: Menglong Dong --- kernel/trace/trace_wprobe.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/kernel/trace/trace_wprobe.c b/kernel/trace/trace_wprobe.c index 4b00a8e917c1..98605b207f43 100644 --- a/kernel/trace/trace_wprobe.c +++ b/kernel/trace/trace_wprobe.c @@ -173,8 +173,8 @@ static int __register_trace_wprobe(struct trace_wprobe = *tw) attr.bp_type =3D tw->type; =20 tw->bp_event =3D register_wide_hw_breakpoint(&attr, wprobe_perf_handler, = tw); - if (IS_ERR((void * __force)tw->bp_event)) { - int ret =3D PTR_ERR((void * __force)tw->bp_event); + if (IS_ERR_PCPU(tw->bp_event)) { + int ret =3D PTR_ERR_PCPU(tw->bp_event); =20 tw->bp_event =3D NULL; return ret; From nobody Sat Feb 7 15:22:00 2026 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A808A26560A; Wed, 28 Jan 2026 14:10:12 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769609412; cv=none; b=h2E/ANzu77tavyuHrSOCPH6dzDVu2JO3vUZwyL+XKb73RyIyGcvuondUDhGAkNZQg0G/CNOjWctoIaqMFDxuVDbbdbi+CJ59bJrO89EODByTWP3hOU2GONfmC3+yLWmzlYq+/MkuO9OgzRxfcPyd/kOHmZzkO0Ql5tZ16OS3CRY= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769609412; c=relaxed/simple; bh=FwofjpaBIP939xlrMtaUiM5BSY7RsnvWLxex1YGY+5Y=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=f1P2nh8kPLCgxERthuuscU5/oElJEDBZ5ixLVSHNFNxt20ntb4sv5g+GbnERlcHoB/Waa+T2ujp75+j58urD3s3q2OBx+qEwYcAwhKG9TAu0lkTw0oFXyGv/+0pUK3xxMxRWuqbeeuKqHHp/NbvSt4rZliRTvfi2Zi2nnrdOZA4= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=iUmaSUtA; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="iUmaSUtA" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4A677C2BC9E; Wed, 28 Jan 2026 14:10:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1769609412; bh=FwofjpaBIP939xlrMtaUiM5BSY7RsnvWLxex1YGY+5Y=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=iUmaSUtAoRo8DZ83BAyA2fqm25sMgWPESKcbIbjv/pt4C6eiEosFAtB0l1563j/PP /JoK7wKgdZQkwCiTZ4FateTQOQ/6OO2Am2pP+Otmhbjv0zNf/S72Lx39fxZkHKoQnz pqXzDDf9yxSKXbOBgi+YCHVm3TXT+9w/TCGYCMB3LOJt7iXKTIV/G9vqrR4SlVfL4J Ym/zzihVuZ0PSxVaOxaWevBu9FI+dSa0z70MPum7g05TTISvwecx5imjqcAOeMxG7k X0yeQ/sPq8I75Xv70Cm8OacT1SEdLDH9Z7LOzKh8atuOR1fqfPzKYDSW30uB02OSaM YvQuNgtE3xjXg== From: "Masami Hiramatsu (Google)" To: Steven Rostedt , Peter Zijlstra , Ingo Molnar , x86@kernel.org Cc: Jinchao Wang , Mathieu Desnoyers , Masami Hiramatsu , Thomas Gleixner , Borislav Petkov , Dave Hansen , "H . Peter Anvin" , Alexander Shishkin , Ian Rogers , linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-perf-users@vger.kernel.org Subject: [PATCH v6 06/11] tracing: wprobe: Use a new seq_print_ip_sym_offset() wrapper Date: Wed, 28 Jan 2026 23:10:05 +0900 Message-ID: <176960940550.182525.13602015884277238925.stgit@devnote2> X-Mailer: git-send-email 2.43.0 In-Reply-To: <176960933881.182525.11984731584313026309.stgit@devnote2> References: <176960933881.182525.11984731584313026309.stgit@devnote2> User-Agent: StGit/0.19 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable From: Masami Hiramatsu (Google) Use a new seq_print_ip_sym_offset() wrapper function instead of using TRACE_ITER(SYM_OFFSET) mask directly. Link: https://lore.kernel.org/all/176226550596.59499.18020648957674458755.s= tgit@devnote2/ Signed-off-by: Masami Hiramatsu (Google) --- kernel/trace/trace_wprobe.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/kernel/trace/trace_wprobe.c b/kernel/trace/trace_wprobe.c index 98605b207f43..eae952a4f9e9 100644 --- a/kernel/trace/trace_wprobe.c +++ b/kernel/trace/trace_wprobe.c @@ -20,6 +20,7 @@ #include =20 #include "trace_dynevent.h" +#include "trace_output.h" #include "trace_probe.h" #include "trace_probe_kernel.h" #include "trace_probe_tmpl.h" @@ -260,7 +261,7 @@ print_wprobe_event(struct trace_iterator *iter, int fla= gs, =20 trace_seq_printf(s, "%s: (", trace_probe_name(tp)); =20 - if (!seq_print_ip_sym(s, field->ip, flags | TRACE_ITER_SYM_OFFSET)) + if (!seq_print_ip_sym_offset(s, field->ip, flags)) goto out; =20 trace_seq_putc(s, ')'); From nobody Sat Feb 7 15:22:00 2026 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id EA358353EF7; Wed, 28 Jan 2026 14:10:24 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769609425; cv=none; b=NvmJG/PPC/N+GZ2OQcq1mF8WDkPGfSW1eILlj2GXOZaoeY9wPx0CbJgKXqf8ZwwjmZtF57hVYxmasT73K75UAHuaT9O7afcZMC5YbI0e6zgNayRAzBk6LyADG9oB1s/OdhOidFHAbR6UCNYWlUngAs0OS90/NvgiMLxeK3Z2StA= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769609425; c=relaxed/simple; bh=JEU4WBIYuuT37OeBiwFms6X98mwAE00m7G+jZVkf2xE=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=D7vZPNOG1+6DuD+06GJzlucIMzstii/eiBHsM7BMeDRmCVQC+Ul4LRHWa/Vl13+K6kKEchaHv75qq9k6rH7lH0yOsS1CultsktqMqREbQPzuroX1nrt7Ce/OfBhvmCOYbWfT+7B7UxsDsOeib6fpK/QncHndk1ianHM1Zxxyfsg= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=j+gY1KWo; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="j+gY1KWo" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2A222C116C6; Wed, 28 Jan 2026 14:10:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1769609423; bh=JEU4WBIYuuT37OeBiwFms6X98mwAE00m7G+jZVkf2xE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=j+gY1KWoUe54F9EGbxPFq5X6v1mm9baFbK420/hfcSXqxEZciabIH3NsKhfQWhNLu wotA04f2ykdrNP72goTabPVlMAVN4DVMPDZrHBrOQCVf4KjRdCH6EmRDzdoj/S2SzG Eby715VMGaTl2CL3VdmxoAXXBPSeIQlfkRuaGWWG24ET0kmP0BqWCDGD7rFK6D8lWr gsNepX4w8z3L5nFpYcaCuvTb2FxmXXNr4nXu5rkNCbpRGau67ZfOrpAXErt70aFeu9 qihuBbafv41ira/SddjpN3bAX6b9KDg3rzwe6+sw5f3uNYxqe4Vq52YmTCdQIOJAGS 9ocey1ZTJhK9g== From: "Masami Hiramatsu (Google)" To: Steven Rostedt , Peter Zijlstra , Ingo Molnar , x86@kernel.org Cc: Jinchao Wang , Mathieu Desnoyers , Masami Hiramatsu , Thomas Gleixner , Borislav Petkov , Dave Hansen , "H . Peter Anvin" , Alexander Shishkin , Ian Rogers , linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-perf-users@vger.kernel.org Subject: [PATCH v6 07/11] x86/hw_breakpoint: Unify breakpoint install/uninstall Date: Wed, 28 Jan 2026 23:10:17 +0900 Message-ID: <176960941779.182525.2222840032895902835.stgit@devnote2> X-Mailer: git-send-email 2.43.0 In-Reply-To: <176960933881.182525.11984731584313026309.stgit@devnote2> References: <176960933881.182525.11984731584313026309.stgit@devnote2> User-Agent: StGit/0.19 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable From: Jinchao Wang Consolidate breakpoint management to reduce code duplication. The diffstat was misleading, so the stripped code size is compared instead. After refactoring, it is reduced from 11976 bytes to 11448 bytes on my x86_64 system built with clang. This also makes it easier to introduce arch_reinstall_hw_breakpoint(). In addition, including linux/types.h to fix a missing build dependency. Signed-off-by: Jinchao Wang Reviewed-by: Masami Hiramatsu (Google) --- arch/x86/include/asm/hw_breakpoint.h | 6 + arch/x86/kernel/hw_breakpoint.c | 141 +++++++++++++++++++-----------= ---- 2 files changed, 84 insertions(+), 63 deletions(-) diff --git a/arch/x86/include/asm/hw_breakpoint.h b/arch/x86/include/asm/hw= _breakpoint.h index 0bc931cd0698..aa6adac6c3a2 100644 --- a/arch/x86/include/asm/hw_breakpoint.h +++ b/arch/x86/include/asm/hw_breakpoint.h @@ -5,6 +5,7 @@ #include =20 #define __ARCH_HW_BREAKPOINT_H +#include =20 /* * The name should probably be something dealt in @@ -18,6 +19,11 @@ struct arch_hw_breakpoint { u8 type; }; =20 +enum bp_slot_action { + BP_SLOT_ACTION_INSTALL, + BP_SLOT_ACTION_UNINSTALL, +}; + #include #include #include diff --git a/arch/x86/kernel/hw_breakpoint.c b/arch/x86/kernel/hw_breakpoin= t.c index f846c15f21ca..877509539300 100644 --- a/arch/x86/kernel/hw_breakpoint.c +++ b/arch/x86/kernel/hw_breakpoint.c @@ -49,7 +49,6 @@ static DEFINE_PER_CPU(unsigned long, cpu_debugreg[HBP_NUM= ]); */ static DEFINE_PER_CPU(struct perf_event *, bp_per_reg[HBP_NUM]); =20 - static inline unsigned long __encode_dr7(int drnum, unsigned int len, unsigned int type) { @@ -86,96 +85,112 @@ int decode_dr7(unsigned long dr7, int bpnum, unsigned = *len, unsigned *type) } =20 /* - * Install a perf counter breakpoint. - * - * We seek a free debug address register and use it for this - * breakpoint. Eventually we enable it in the debug control register. - * - * Atomic: we hold the counter->ctx->lock and we only handle variables - * and registers local to this cpu. + * We seek a slot and change it or keep it based on the action. + * Returns slot number on success, negative error on failure. + * Must be called with IRQs disabled. */ -int arch_install_hw_breakpoint(struct perf_event *bp) +static int manage_bp_slot(struct perf_event *bp, enum bp_slot_action actio= n) { - struct arch_hw_breakpoint *info =3D counter_arch_bp(bp); - unsigned long *dr7; - int i; - - lockdep_assert_irqs_disabled(); + struct perf_event *old_bp; + struct perf_event *new_bp; + int slot; + + switch (action) { + case BP_SLOT_ACTION_INSTALL: + old_bp =3D NULL; + new_bp =3D bp; + break; + case BP_SLOT_ACTION_UNINSTALL: + old_bp =3D bp; + new_bp =3D NULL; + break; + default: + return -EINVAL; + } =20 - for (i =3D 0; i < HBP_NUM; i++) { - struct perf_event **slot =3D this_cpu_ptr(&bp_per_reg[i]); + for (slot =3D 0; slot < HBP_NUM; slot++) { + struct perf_event **curr =3D this_cpu_ptr(&bp_per_reg[slot]); =20 - if (!*slot) { - *slot =3D bp; - break; + if (*curr =3D=3D old_bp) { + *curr =3D new_bp; + return slot; } } =20 - if (WARN_ONCE(i =3D=3D HBP_NUM, "Can't find any breakpoint slot")) - return -EBUSY; + if (old_bp) { + WARN_ONCE(1, "Can't find matching breakpoint slot"); + return -EINVAL; + } + + WARN_ONCE(1, "No free breakpoint slots"); + return -EBUSY; +} + +static void setup_hwbp(struct arch_hw_breakpoint *info, int slot, bool ena= ble) +{ + unsigned long dr7; =20 - set_debugreg(info->address, i); - __this_cpu_write(cpu_debugreg[i], info->address); + set_debugreg(info->address, slot); + __this_cpu_write(cpu_debugreg[slot], info->address); =20 - dr7 =3D this_cpu_ptr(&cpu_dr7); - *dr7 |=3D encode_dr7(i, info->len, info->type); + dr7 =3D this_cpu_read(cpu_dr7); + if (enable) + dr7 |=3D encode_dr7(slot, info->len, info->type); + else + dr7 &=3D ~__encode_dr7(slot, info->len, info->type); =20 /* - * Ensure we first write cpu_dr7 before we set the DR7 register. - * This ensures an NMI never see cpu_dr7 0 when DR7 is not. + * Enabling: + * Ensure we first write cpu_dr7 before we set the DR7 register. + * This ensures an NMI never see cpu_dr7 0 when DR7 is not. */ + if (enable) + this_cpu_write(cpu_dr7, dr7); + barrier(); =20 - set_debugreg(*dr7, 7); + set_debugreg(dr7, 7); + if (info->mask) - amd_set_dr_addr_mask(info->mask, i); + amd_set_dr_addr_mask(enable ? info->mask : 0, slot); =20 - return 0; + /* + * Disabling: + * Ensure the write to cpu_dr7 is after we've set the DR7 register. + * This ensures an NMI never see cpu_dr7 0 when DR7 is not. + */ + if (!enable) + this_cpu_write(cpu_dr7, dr7); } =20 /* - * Uninstall the breakpoint contained in the given counter. - * - * First we search the debug address register it uses and then we disable - * it. - * - * Atomic: we hold the counter->ctx->lock and we only handle variables - * and registers local to this cpu. + * find suitable breakpoint slot and set it up based on the action */ -void arch_uninstall_hw_breakpoint(struct perf_event *bp) +static int arch_manage_bp(struct perf_event *bp, enum bp_slot_action actio= n) { - struct arch_hw_breakpoint *info =3D counter_arch_bp(bp); - unsigned long dr7; - int i; + struct arch_hw_breakpoint *info; + int slot; =20 lockdep_assert_irqs_disabled(); =20 - for (i =3D 0; i < HBP_NUM; i++) { - struct perf_event **slot =3D this_cpu_ptr(&bp_per_reg[i]); - - if (*slot =3D=3D bp) { - *slot =3D NULL; - break; - } - } - - if (WARN_ONCE(i =3D=3D HBP_NUM, "Can't find any breakpoint slot")) - return; + slot =3D manage_bp_slot(bp, action); + if (slot < 0) + return slot; =20 - dr7 =3D this_cpu_read(cpu_dr7); - dr7 &=3D ~__encode_dr7(i, info->len, info->type); + info =3D counter_arch_bp(bp); + setup_hwbp(info, slot, action !=3D BP_SLOT_ACTION_UNINSTALL); =20 - set_debugreg(dr7, 7); - if (info->mask) - amd_set_dr_addr_mask(0, i); + return 0; +} =20 - /* - * Ensure the write to cpu_dr7 is after we've set the DR7 register. - * This ensures an NMI never see cpu_dr7 0 when DR7 is not. - */ - barrier(); +int arch_install_hw_breakpoint(struct perf_event *bp) +{ + return arch_manage_bp(bp, BP_SLOT_ACTION_INSTALL); +} =20 - this_cpu_write(cpu_dr7, dr7); +void arch_uninstall_hw_breakpoint(struct perf_event *bp) +{ + arch_manage_bp(bp, BP_SLOT_ACTION_UNINSTALL); } =20 static int arch_bp_generic_len(int x86_len) From nobody Sat Feb 7 15:22:00 2026 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D978628E571; Wed, 28 Jan 2026 14:10:34 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769609434; cv=none; b=ZXjVrAOYiFeRK/1gHrH6wEjV/4/e31APNF4Q4naNb9Y4fhd9EjeHOlWDLlGCrR9H7EsHHqpQT88euRvOLv28DgfZKrT4J8Sj/u+F+WSiQOeFlAvHf0eOXKEaiP+Mts/u7ZTaEGegbVg2jYNHvAdaElJb2z3qF5GM+3uMiGCieXQ= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769609434; c=relaxed/simple; bh=2fcSX4kIwFIDKw76TQlcptyp8280Ha4c+S8Uiz27Pus=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=hQBQm928pcgxX23muTKuiLSkh3jihEahNVjfhjsC4V53jPL39yf+zSHlmbcCkGBeA1WwkL6WyuP+vdH052lFmvRkWuDXt1874ngTmK8kzXvG78WI3FfTBYPEF6XVcgMjfxhwDWd6efr7RktZwsb+uzil6T2MwepaaYKFmG57VnI= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=S9jSmVOE; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="S9jSmVOE" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E212EC4CEF1; Wed, 28 Jan 2026 14:10:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1769609434; bh=2fcSX4kIwFIDKw76TQlcptyp8280Ha4c+S8Uiz27Pus=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=S9jSmVOEXNPzRwPP7S+cOYeUwneflBkacqlSmASiIjlD2x0oxBFcveuEmSf9IP3VC 1ZjS0P4Ye3AApJKg7aqhxgU0OfskLJv6yT2bQ8yQDaoGppDn8AcXlUgv7QRP69M6/b ggsEJ/NUjATvcgW89m6HtlbKZkc3Hg6PVSLER+0Cu2D2GDgVDtVH3H2VrHbMNffcKK HqXvFyBYzrb7/BPTDdvLxrrZIAprJ3424TOWXpwBCfIhEM2J6UIvPWuxHNdf+A67Mc ZrjW+KXAj5qsLnX5oGpxoPeewo7CBTFQtuJPuiJ5UgwB0VeACqFK8VoAK7RXrWsh+z ZvrNsUctaqpaw== From: "Masami Hiramatsu (Google)" To: Steven Rostedt , Peter Zijlstra , Ingo Molnar , x86@kernel.org Cc: Jinchao Wang , Mathieu Desnoyers , Masami Hiramatsu , Thomas Gleixner , Borislav Petkov , Dave Hansen , "H . Peter Anvin" , Alexander Shishkin , Ian Rogers , linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-perf-users@vger.kernel.org Subject: [PATCH v6 08/11] x86/hw_breakpoint: Add arch_reinstall_hw_breakpoint Date: Wed, 28 Jan 2026 23:10:28 +0900 Message-ID: <176960942877.182525.17095859955520882013.stgit@devnote2> X-Mailer: git-send-email 2.43.0 In-Reply-To: <176960933881.182525.11984731584313026309.stgit@devnote2> References: <176960933881.182525.11984731584313026309.stgit@devnote2> User-Agent: StGit/0.19 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable From: Jinchao Wang The new arch_reinstall_hw_breakpoint() function can be used in an atomic context, unlike the more expensive free and re-allocation path. This allows callers to efficiently re-establish an existing breakpoint. Signed-off-by: Jinchao Wang Reviewed-by: Masami Hiramatsu (Google) --- arch/x86/include/asm/hw_breakpoint.h | 2 ++ arch/x86/kernel/hw_breakpoint.c | 9 +++++++++ 2 files changed, 11 insertions(+) diff --git a/arch/x86/include/asm/hw_breakpoint.h b/arch/x86/include/asm/hw= _breakpoint.h index aa6adac6c3a2..c22cc4e87fc5 100644 --- a/arch/x86/include/asm/hw_breakpoint.h +++ b/arch/x86/include/asm/hw_breakpoint.h @@ -21,6 +21,7 @@ struct arch_hw_breakpoint { =20 enum bp_slot_action { BP_SLOT_ACTION_INSTALL, + BP_SLOT_ACTION_REINSTALL, BP_SLOT_ACTION_UNINSTALL, }; =20 @@ -65,6 +66,7 @@ extern int hw_breakpoint_exceptions_notify(struct notifie= r_block *unused, =20 =20 int arch_install_hw_breakpoint(struct perf_event *bp); +int arch_reinstall_hw_breakpoint(struct perf_event *bp); void arch_uninstall_hw_breakpoint(struct perf_event *bp); void hw_breakpoint_pmu_read(struct perf_event *bp); void hw_breakpoint_pmu_unthrottle(struct perf_event *bp); diff --git a/arch/x86/kernel/hw_breakpoint.c b/arch/x86/kernel/hw_breakpoin= t.c index 877509539300..9af8d81075db 100644 --- a/arch/x86/kernel/hw_breakpoint.c +++ b/arch/x86/kernel/hw_breakpoint.c @@ -100,6 +100,10 @@ static int manage_bp_slot(struct perf_event *bp, enum = bp_slot_action action) old_bp =3D NULL; new_bp =3D bp; break; + case BP_SLOT_ACTION_REINSTALL: + old_bp =3D bp; + new_bp =3D bp; + break; case BP_SLOT_ACTION_UNINSTALL: old_bp =3D bp; new_bp =3D NULL; @@ -188,6 +192,11 @@ int arch_install_hw_breakpoint(struct perf_event *bp) return arch_manage_bp(bp, BP_SLOT_ACTION_INSTALL); } =20 +int arch_reinstall_hw_breakpoint(struct perf_event *bp) +{ + return arch_manage_bp(bp, BP_SLOT_ACTION_REINSTALL); +} + void arch_uninstall_hw_breakpoint(struct perf_event *bp) { arch_manage_bp(bp, BP_SLOT_ACTION_UNINSTALL); From nobody Sat Feb 7 15:22:00 2026 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 0111D254AF5; Wed, 28 Jan 2026 14:10:45 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769609446; cv=none; b=KEPVnIshEyz5b78vYmaVGkFeZBOvtCeO4G+pvdfEIsGcZln/SbxaKHwc9EcuWL456byZwDQyx8uXtmd81RPxotXuAr1qNeLZ1TIECUojSDHWczl9YYy/xcE808lZ4deRH1WQP2Zp/yYltzFSsBFpcw0Pte7F7b3HXx8rd28jVrI= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769609446; c=relaxed/simple; bh=gS6F2gUz4xmw5bm/75SMXUtg9Egrc09+IKTnsYy0B7A=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=OE1/z6USJ5BhQfAFWZRgJCsj2o7r1beRj8kYFoK15lER6Guozgj1t4hcSqWrBP61coMPORPXFaQOzPG6sabTCdNLEKq3P1hM0was2P/k4zpvuZEuXWthflwNmISdj5wGo+UHBowR8NiTc02FKb/yW7BHyeeJQEfN3mOiTCbWRZs= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=gvHwaEd6; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="gvHwaEd6" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 469E3C16AAE; Wed, 28 Jan 2026 14:10:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1769609445; bh=gS6F2gUz4xmw5bm/75SMXUtg9Egrc09+IKTnsYy0B7A=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=gvHwaEd6H5XUZi8Zvg58e/Y7+MQ16JW9f1XyCi/wS6gMLA5sumGPnwV40a9hHY/4+ km/1Pl2Sbn4LodyxtARtuWkz9cqodacSm1WthIPKK8C4TK79UXhln9fxcRZRI1R3J5 h9nJsgfW3A6AdgpdQqSqyj8jKAALqHS9iKjiO83VJv9/8ixS7maqAJ99HCvuWnbwrj tD6Xx1h03SAY2LetD4m2vUxOLNtMu1df+egelvYN9v6uJ23I//wHVt6UYARifEy7wF hQBVDgB5VQ4hcSd25sXcW1uDaekXAXTh8S7q1/7MDbZZhN3MEs2wtCiEC86ssFaLzO +nNODQu3AJTSQ== From: "Masami Hiramatsu (Google)" To: Steven Rostedt , Peter Zijlstra , Ingo Molnar , x86@kernel.org Cc: Jinchao Wang , Mathieu Desnoyers , Masami Hiramatsu , Thomas Gleixner , Borislav Petkov , Dave Hansen , "H . Peter Anvin" , Alexander Shishkin , Ian Rogers , linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-perf-users@vger.kernel.org Subject: [PATCH v6 09/11] HWBP: Add modify_wide_hw_breakpoint_local() API Date: Wed, 28 Jan 2026 23:10:39 +0900 Message-ID: <176960943980.182525.6706762040751972161.stgit@devnote2> X-Mailer: git-send-email 2.43.0 In-Reply-To: <176960933881.182525.11984731584313026309.stgit@devnote2> References: <176960933881.182525.11984731584313026309.stgit@devnote2> User-Agent: StGit/0.19 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable From: Masami Hiramatsu (Google) Add modify_wide_hw_breakpoint_local() arch-wide interface which allows hwbp users to update watch address on-line. This is available if the arch supports CONFIG_HAVE_REINSTALL_HW_BREAKPOINT. Note that this allows to change the type only for compatible types, because it does not release and reserve the hwbp slot based on type. For instance, you can not change HW_BREAKPOINT_W to HW_BREAKPOINT_X. Signed-off-by: Masami Hiramatsu (Google) --- Changes in v4: - Update kerneldoc comment about modify_wide_hw_breakpoint_local according to Randy's comment. Changes in v2: - Check type compatibility by checking slot. (Thanks Jinchao!) --- arch/Kconfig | 10 ++++++++++ arch/x86/Kconfig | 1 + include/linux/hw_breakpoint.h | 6 ++++++ kernel/events/hw_breakpoint.c | 37 +++++++++++++++++++++++++++++++++++++ 4 files changed, 54 insertions(+) diff --git a/arch/Kconfig b/arch/Kconfig index 64adda21c5f6..eb709726166c 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -463,6 +463,16 @@ config HAVE_POST_BREAKPOINT_HOOK Select this option if your arch implements breakpoints overflow handler hooks after the target memory is modified. =20 +config HAVE_REINSTALL_HW_BREAKPOINT + bool + depends on HAVE_HW_BREAKPOINT + help + Depending on the arch implementation of hardware breakpoints, + some of them are able to update the breakpoint configuration + without release and reserve the hardware breakpoint register. + What configuration is able to update depends on hardware and + software implementation. + config HAVE_USER_RETURN_NOTIFIER bool =20 diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 755fd3bd4334..5a14871c8a02 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -247,6 +247,7 @@ config X86 select HAVE_GCC_PLUGINS select HAVE_HW_BREAKPOINT select HAVE_POST_BREAKPOINT_HOOK + select HAVE_REINSTALL_HW_BREAKPOINT select HAVE_IOREMAP_PROT select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64 select HAVE_IRQ_TIME_ACCOUNTING diff --git a/include/linux/hw_breakpoint.h b/include/linux/hw_breakpoint.h index db199d653dd1..ea373f2587f8 100644 --- a/include/linux/hw_breakpoint.h +++ b/include/linux/hw_breakpoint.h @@ -81,6 +81,9 @@ register_wide_hw_breakpoint(struct perf_event_attr *attr, perf_overflow_handler_t triggered, void *context); =20 +extern int modify_wide_hw_breakpoint_local(struct perf_event *bp, + struct perf_event_attr *attr); + extern int register_perf_hw_breakpoint(struct perf_event *bp); extern void unregister_hw_breakpoint(struct perf_event *bp); extern void unregister_wide_hw_breakpoint(struct perf_event * __percpu *cp= u_events); @@ -124,6 +127,9 @@ register_wide_hw_breakpoint(struct perf_event_attr *att= r, perf_overflow_handler_t triggered, void *context) { return NULL; } static inline int +modify_wide_hw_breakpoint_local(struct perf_event *bp, + struct perf_event_attr *attr) { return -ENOSYS; } +static inline int register_perf_hw_breakpoint(struct perf_event *bp) { return -ENOSYS; } static inline void unregister_hw_breakpoint(struct perf_event *bp) { } static inline void diff --git a/kernel/events/hw_breakpoint.c b/kernel/events/hw_breakpoint.c index 8ec2cb688903..5ee1522a99c9 100644 --- a/kernel/events/hw_breakpoint.c +++ b/kernel/events/hw_breakpoint.c @@ -887,6 +887,43 @@ void unregister_wide_hw_breakpoint(struct perf_event *= __percpu *cpu_events) } EXPORT_SYMBOL_GPL(unregister_wide_hw_breakpoint); =20 +/** + * modify_wide_hw_breakpoint_local - update breakpoint config for local CPU + * @bp: the hwbp perf event for this CPU + * @attr: the new attribute for @bp + * + * This does not release and reserve the slot of a HWBP; it just reuses the + * current slot on local CPU. So the users must update the other CPUs by + * themselves. + * Also, since this does not release/reserve the slot, this can not change= the + * type to incompatible type of the HWBP. + * Return err if attr is invalid or the CPU fails to update debug register + * for new @attr. + */ +#ifdef CONFIG_HAVE_REINSTALL_HW_BREAKPOINT +int modify_wide_hw_breakpoint_local(struct perf_event *bp, + struct perf_event_attr *attr) +{ + int ret; + + if (find_slot_idx(bp->attr.bp_type) !=3D find_slot_idx(attr->bp_type)) + return -EINVAL; + + ret =3D hw_breakpoint_arch_parse(bp, attr, counter_arch_bp(bp)); + if (ret) + return ret; + + return arch_reinstall_hw_breakpoint(bp); +} +#else +int modify_wide_hw_breakpoint_local(struct perf_event *bp, + struct perf_event_attr *attr) +{ + return -EOPNOTSUPP; +} +#endif +EXPORT_SYMBOL_GPL(modify_wide_hw_breakpoint_local); + /** * hw_breakpoint_is_used - check if breakpoints are currently used * From nobody Sat Feb 7 15:22:00 2026 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4D72E23B62B; Wed, 28 Jan 2026 14:10:57 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769609457; cv=none; b=D81Gm70cL9VTfFMyozneSwSkBDf/SRv0E/LRK+IkNJOxVALAlvBzRCUBp/WPygo4nGoTX4AfPzK6Ts38tEcmY6QwsxKRzrVVaDmgX8saxso7pF1gAkLWCWTWX4+ZkFVWKlSULI83C4lEmJrRwgzHFYHE4LJzZ+rYOF1WoGvN7wY= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769609457; c=relaxed/simple; bh=ot0JvOp5ngooyVykq1FKETxSlWUQZAX9UNE563yz0XE=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=BoGNxoGjU542aM29SUloDzsa3o1/88ZFbhbs3+VLwhEe4alK98yX3e3JvnY1JSupDu3RLrmvBizE/FgmDFM3g7bQnDkrpK/K+GqWRUbW3m0JDTkpWJAWoUDTpeMoaVD2+09yafA7GDt/zq6jwafMpongjlrDnxQ7FaGaff3xAbs= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=snnrqiyy; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="snnrqiyy" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 55F73C4CEF7; Wed, 28 Jan 2026 14:10:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1769609456; bh=ot0JvOp5ngooyVykq1FKETxSlWUQZAX9UNE563yz0XE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=snnrqiyy3WBBC0WFS5tR4Ti1+FTKKJZzdjO17X6oscLVnCbDz5L91dad68HCM2dKc hsDzqEvLyrMjMlu9X+WInI9rlLp9w4/tQ7eEUw/xmzNErAPDr+NcfOCs1f+/OAolKi KuPXfZPUovEYDJjr92BCWVskDaoHETTPRt1pcF91VCV2RJIVV50i5irwyaG3fh8r/4 t6vEBHr3ctQEWQ7oOFdpR0AbfWRLRpgq+EZ4I+vcqeDFmZpDkxe5JN6u7a66cwXvdx SeTtqvvuORuod+EAxMxChvgUml9jSWzcr4GwAsViodRTk+XNZDL6x3CnAYkbEsgDVj lGzdLW8diwEfA== From: "Masami Hiramatsu (Google)" To: Steven Rostedt , Peter Zijlstra , Ingo Molnar , x86@kernel.org Cc: Jinchao Wang , Mathieu Desnoyers , Masami Hiramatsu , Thomas Gleixner , Borislav Petkov , Dave Hansen , "H . Peter Anvin" , Alexander Shishkin , Ian Rogers , linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-perf-users@vger.kernel.org Subject: [PATCH v6 10/11] tracing: wprobe: Add wprobe event trigger Date: Wed, 28 Jan 2026 23:10:51 +0900 Message-ID: <176960945089.182525.5049472955827015782.stgit@devnote2> X-Mailer: git-send-email 2.43.0 In-Reply-To: <176960933881.182525.11984731584313026309.stgit@devnote2> References: <176960933881.182525.11984731584313026309.stgit@devnote2> User-Agent: StGit/0.19 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable From: Masami Hiramatsu (Google) Add wprobe event trigger to set and clear the watch event dynamically. This allows us to set an watchpoint on a given local variables and a slab object instead of static objects. The trigger syntax is below: - set_wprobe:WPROBE:FIELD[+OFFSET] [if FILTER] - clear_wprobe:WPROBE[:FIELD[+OFFSET]] [if FILTER] set_wprobe sets the address pointed by FIELD[+offset] to the WPROBE event. The FIELD is the field name of trigger event. clear_wprobe clears the watch address of WPROBE event. If the FIELD option is specified, it clears only if the current watch address is same as the given FIELD[+OFFSET] value. The set_wprobe trigger does not change the type and length, these must be set when creating a new wprobe. Also, the WPROBE event must be disabled when setting the new trigger and it will be busy afterwards. Recommended usage is to add a new wprobe at NULL address and keep disabled. Signed-off-by: Masami Hiramatsu (Google) --- Changes in v6: - Update according to the latest change of trigger ops. Changes in v5: - Following the suggestions, the documentation was revised to suit rst. Changes in v3: - Add FIELD option support for clear_wprobe and update document. - Fix to unregister/free event_trigger_data on file correctly. - Fix syntax comments. Changes in v2: - Getting local cpu perf_event from trace_wprobe directly. - Remove trace_wprobe_local_perf() because it is conditionally unused. - Make CONFIG_WPROBE_TRIGGERS a hidden config. --- Documentation/trace/wprobetrace.rst | 86 +++++++ include/linux/trace_events.h | 1=20 kernel/trace/Kconfig | 10 + kernel/trace/trace_wprobe.c | 415 +++++++++++++++++++++++++++++++= ++++ 4 files changed, 512 insertions(+) diff --git a/Documentation/trace/wprobetrace.rst b/Documentation/trace/wpro= betrace.rst index 025b4c39b809..e3e82c617218 100644 --- a/Documentation/trace/wprobetrace.rst +++ b/Documentation/trace/wprobetrace.rst @@ -67,3 +67,89 @@ Here is an example to add a wprobe event on a variable `= jiffies`. -0 [000] d.Z1. 717.026373: my_jiffies: (tick_do_up= date_jiffies64+0xbe/0x130) =20 You can see the code which writes to `jiffies` is `tick_do_update_jiffies6= 4()`. + +Combination with trigger action +------------------------------- +The event trigger action can extend the utilization of this wprobe. + +- set_wprobe:WPEVENT:FIELD[+|-ADJUST] +- clear_wprobe:WPEVENT[:FIELD[+|-]ADJUST] + +Set these triggers to the target event, then the WPROBE event will be +setup to trace the memory access at FIELD[+|-ADJUST] address. +When clear_wprobe is hit, if FIELD is NOT specified, the WPEVENT is +forcibly cleared. If FIELD[[+|-]ADJUST] is set, it clears WPEVENT only +if its watching address is the same as the FIELD[[+|-]ADJUST] value. + +Notes: +The set_wprobe trigger does not change the type and length, these +must be set when creating a new wprobe. + +The WPROBE event must be disabled when setting the new trigger +and it will be busy afterwards. Recommended usage is to add a new +wprobe at NULL address and keep disabled. + + +For example, trace the first 8 bytes of the dentry data structure passed +to do_truncate() until it is deleted by __dentry_kill(). +(Note: all tracefs setup uses '>>' so that it does not kick do_truncate()) +:: + + # echo 'w:watch rw@0:8 address=3D$addr value=3D+0($addr)' >> dynamic_eve= nts + # echo 'f:truncate do_truncate dentry=3D$arg2' >> dynamic_events + # echo 'set_wprobe:watch:dentry' >> events/fprobes/truncate/trigger + # echo 'f:dentry_kill __dentry_kill dentry=3D$arg1' >> dynamic_events + # echo 'clear_wprobe:watch:dentry' >> events/fprobes/dentry_kill/trigger + # echo 1 >> events/fprobes/truncate/enable + # echo 1 >> events/fprobes/dentry_kill/enable + + # echo aaa > /tmp/hoge + # echo bbb > /tmp/hoge + # echo ccc > /tmp/hoge + # rm /tmp/hoge + +Then, the trace data will show:: + + # tracer: nop + # + # entries-in-buffer/entries-written: 16/16 #P:8 + # + # _-----=3D> irqs-off/BH-disabled + # / _----=3D> need-resched + # | / _---=3D> hardirq/softirq + # || / _--=3D> preempt-depth + # ||| / _-=3D> migrate-disable + # |||| / delay + # TASK-PID CPU# ||||| TIMESTAMP FUNCTION + # | | | ||||| | | + sh-113 [004] ..... 6.467444: truncate: (do_truncat= e+0x4/0x120) dentry=3D0xffff8880044f0fd8 + sh-113 [004] ..Zff 6.468534: watch: (lookup_fast+0= xaa/0x150) address=3D0xffff8880044f0fd8 value=3D0x200080 + sh-113 [004] ..Zff 6.468542: watch: (step_into+0x8= 2/0x360) address=3D0xffff8880044f0fd8 value=3D0x200080 + sh-113 [004] ..Zff 6.468547: watch: (step_into+0x9= f/0x360) address=3D0xffff8880044f0fd8 value=3D0x200080 + sh-113 [004] ..Zff 6.468553: watch: (path_openat+0= xb3a/0xe70) address=3D0xffff8880044f0fd8 value=3D0x200080 + sh-113 [004] ..Zff 6.468557: watch: (path_openat+0= xb9a/0xe70) address=3D0xffff8880044f0fd8 value=3D0x200080 + sh-113 [004] ..... 6.468563: truncate: (do_truncat= e+0x4/0x120) dentry=3D0xffff8880044f0fd8 + sh-113 [004] ...1. 6.469826: dentry_kill: (__dentr= y_kill+0x0/0x220) dentry=3D0xffff8880044f0ea0 + sh-113 [004] ...1. 6.469859: dentry_kill: (__dentr= y_kill+0x0/0x220) dentry=3D0xffff8880044f0d68 + rm-118 [001] ..Zff 6.472360: watch: (lookup_fast+0= xaa/0x150) address=3D0xffff8880044f0fd8 value=3D0x200080 + rm-118 [001] ..Zff 6.472366: watch: (step_into+0x8= 2/0x360) address=3D0xffff8880044f0fd8 value=3D0x200080 + rm-118 [001] ..Zff 6.472370: watch: (step_into+0x9= f/0x360) address=3D0xffff8880044f0fd8 value=3D0x200080 + rm-118 [001] ..Zff 6.472386: watch: (lookup_fast+0= xaa/0x150) address=3D0xffff8880044f0fd8 value=3D0x200080 + rm-118 [001] ..Zff 6.472390: watch: (step_into+0x8= 2/0x360) address=3D0xffff8880044f0fd8 value=3D0x200080 + rm-118 [001] ..Zff 6.472394: watch: (step_into+0x9= f/0x360) address=3D0xffff8880044f0fd8 value=3D0x200080 + rm-118 [001] ..Zff 6.472415: watch: (lookup_one_qs= tr_excl+0x2c/0x150) address=3D0xffff8880044f0fd8 value=3D0x200080 + rm-118 [001] ..Zff 6.472419: watch: (lookup_one_qs= tr_excl+0xd5/0x150) address=3D0xffff8880044f0fd8 value=3D0x200080 + rm-118 [001] ..Zff 6.472424: watch: (may_delete+0x= 18/0x200) address=3D0xffff8880044f0fd8 value=3D0x200080 + rm-118 [001] ..Zff 6.472428: watch: (may_delete+0x= 194/0x200) address=3D0xffff8880044f0fd8 value=3D0x200080 + rm-118 [001] ..Zff 6.472446: watch: (vfs_unlink+0x= 63/0x1c0) address=3D0xffff8880044f0fd8 value=3D0x200080 + rm-118 [001] d.Z.. 6.472528: watch: (dont_mount+0x= 19/0x30) address=3D0xffff8880044f0fd8 value=3D0x200180 + rm-118 [001] ..Zff 6.472533: watch: (vfs_unlink+0x= 11a/0x1c0) address=3D0xffff8880044f0fd8 value=3D0x200180 + rm-118 [001] ..Zff 6.472538: watch: (vfs_unlink+0x= 12e/0x1c0) address=3D0xffff8880044f0fd8 value=3D0x200180 + rm-118 [001] d.Z1. 6.472543: watch: (d_delete+0x61= /0xa0) address=3D0xffff8880044f0fd8 value=3D0x200080 + rm-118 [001] d.Z1. 6.472547: watch: (dentry_unlink= _inode+0x14/0x110) address=3D0xffff8880044f0fd8 value=3D0x200080 + rm-118 [001] d.Z1. 6.472551: watch: (dentry_unlink= _inode+0x1e/0x110) address=3D0xffff8880044f0fd8 value=3D0x80 + rm-118 [001] d.Z.. 6.472563: watch: (fast_dput+0x8= d/0x120) address=3D0xffff8880044f0fd8 value=3D0x80 + rm-118 [001] ...1. 6.472567: dentry_kill: (__dentr= y_kill+0x0/0x220) dentry=3D0xffff8880044f0fd8 + sh-113 [004] ...2. 6.473049: dentry_kill: (__dentr= y_kill+0x0/0x220) dentry=3D0xffff888006e383a8 + +You can see the watch event is correctly configured on the dentry. diff --git a/include/linux/trace_events.h b/include/linux/trace_events.h index ce6ba759a937..cfd5768e40d2 100644 --- a/include/linux/trace_events.h +++ b/include/linux/trace_events.h @@ -721,6 +721,7 @@ enum event_trigger_type { ETT_EVENT_HIST =3D (1 << 4), ETT_HIST_ENABLE =3D (1 << 5), ETT_EVENT_EPROBE =3D (1 << 6), + ETT_EVENT_WPROBE =3D (1 << 7), }; =20 extern int filter_match_preds(struct event_filter *filter, void *rec); diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig index 087a27b56eb1..8ae02bc26aa8 100644 --- a/kernel/trace/Kconfig +++ b/kernel/trace/Kconfig @@ -861,6 +861,16 @@ config WPROBE_EVENTS Those events can be inserted wherever hardware breakpoints can be set, and record accessed memory address and values. =20 +config WPROBE_TRIGGERS + depends on WPROBE_EVENTS + depends on HAVE_REINSTALL_HW_BREAKPOINT + bool + default y + help + This adds an event trigger which will set the wprobe on a specific + field of an event. This allows user to trace the memory access of + an address pointed by the event field. + config BPF_EVENTS depends on BPF_SYSCALL depends on (KPROBE_EVENTS || UPROBE_EVENTS) && PERF_EVENTS diff --git a/kernel/trace/trace_wprobe.c b/kernel/trace/trace_wprobe.c index eae952a4f9e9..3642cfae73e9 100644 --- a/kernel/trace/trace_wprobe.c +++ b/kernel/trace/trace_wprobe.c @@ -6,6 +6,8 @@ */ #define pr_fmt(fmt) "trace_wprobe: " fmt =20 +#include +#include #include #include #include @@ -14,11 +16,14 @@ #include #include #include +#include #include #include +#include =20 #include =20 +#include "trace.h" #include "trace_dynevent.h" #include "trace_output.h" #include "trace_probe.h" @@ -684,3 +689,413 @@ static __init int init_wprobe_trace(void) } fs_initcall(init_wprobe_trace); =20 +#ifdef CONFIG_WPROBE_TRIGGERS + +static int wprobe_trigger_global_enabled; + +#define SET_WPROBE_STR "set_wprobe" +#define CLEAR_WPROBE_STR "clear_wprobe" +#define WPROBE_DEFAULT_CLEAR_ADDRESS ((unsigned long)&wprobe_trigger_globa= l_enabled) + +struct wprobe_trigger_data { + struct trace_event_file *file; + struct trace_wprobe *tw; + + struct perf_event_attr attr; + raw_spinlock_t lock; /* lock protects attr */ + struct work_struct work;// TBD: use work + IPI or use sched/raw_syscall e= vent? + unsigned int offset; + long adjust; + const char *field; + // size must be unsigned long because it should be an address. + bool clear; +}; + +static int trace_wprobe_update_local(struct trace_wprobe *tw, + struct perf_event_attr *attr) +{ + struct perf_event *bp =3D *this_cpu_ptr(tw->bp_event); + + return modify_wide_hw_breakpoint_local(bp, attr); +} + +static void wprobe_smp_update_func(void *data) +{ + struct wprobe_trigger_data *trigger_data =3D data; + unsigned long flags; + + raw_spin_lock_irqsave(&trigger_data->lock, flags); + trace_wprobe_update_local(trigger_data->tw, &trigger_data->attr); + raw_spin_unlock_irqrestore(&trigger_data->lock, flags); +} + +static void wprobe_work_func(struct work_struct *work) +{ + struct wprobe_trigger_data *data =3D container_of(work, struct wprobe_tri= gger_data, work); + + on_each_cpu(wprobe_smp_update_func, data, false); +} + +static void wprobe_trigger(struct event_trigger_data *data, + struct trace_buffer *buffer, void *rec, + struct ring_buffer_event *event) +{ + struct wprobe_trigger_data *wprobe_data =3D data->private_data; + struct perf_event_attr *attr =3D &wprobe_data->attr; + struct trace_wprobe *tw =3D wprobe_data->tw; + unsigned long addr, flags; + int ret =3D -EBUSY; + + addr =3D *(unsigned long *)(rec + wprobe_data->offset); + addr +=3D wprobe_data->adjust; + + raw_spin_lock_irqsave(&wprobe_data->lock, flags); + + if (!wprobe_data->clear) { + if (tw->addr !=3D WPROBE_DEFAULT_CLEAR_ADDRESS) + goto unlock; + + tw->addr =3D attr->bp_addr =3D addr; + ret =3D trace_wprobe_update_local(tw, attr); + if (WARN_ON_ONCE(ret)) + goto unlock; + clear_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &wprobe_data->file->flags); + } else { + if (tw->addr =3D=3D WPROBE_DEFAULT_CLEAR_ADDRESS) + goto unlock; + if (wprobe_data->field && tw->addr !=3D addr) + goto unlock; + + tw->addr =3D attr->bp_addr =3D WPROBE_DEFAULT_CLEAR_ADDRESS; + ret =3D trace_wprobe_update_local(tw, attr); + if (WARN_ON_ONCE(ret)) + goto unlock; + set_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &wprobe_data->file->flags); + } + schedule_work(&wprobe_data->work); +unlock: + raw_spin_unlock_irqrestore(&wprobe_data->lock, flags); +} + +static void free_wprobe_trigger_data(struct wprobe_trigger_data *wprobe_da= ta) +{ + if (wprobe_data) + kfree(wprobe_data->field); + kfree(wprobe_data); +} + +DEFINE_FREE(free_wprobe_trigger_data, struct wprobe_trigger_data *, free_w= probe_trigger_data(_T)); + +static int wprobe_trigger_print(struct seq_file *m, + struct event_trigger_data *data) +{ + struct wprobe_trigger_data *wprobe_data =3D data->private_data; + + if (wprobe_data->clear) { + seq_printf(m, "%s:%s", CLEAR_WPROBE_STR, + trace_event_name(wprobe_data->file->event_call)); + if (wprobe_data->field) { + seq_printf(m, ":%s%+ld", + wprobe_data->field, wprobe_data->adjust); + } + } else + seq_printf(m, "%s:%s:%s%+ld", SET_WPROBE_STR, + trace_event_name(wprobe_data->file->event_call), + wprobe_data->field, wprobe_data->adjust); + + if (data->filter_str) + seq_printf(m, " if %s\n", data->filter_str); + else + seq_putc(m, '\n'); + + return 0; +} + +static struct wprobe_trigger_data * +wprobe_trigger_alloc(struct trace_wprobe *tw, struct trace_event_file *fil= e, + bool clear) +{ + struct wprobe_trigger_data *wprobe_data; + struct perf_event_attr *attr; + + wprobe_data =3D kzalloc(sizeof(*wprobe_data), GFP_KERNEL); + if (!wprobe_data) + return NULL; + + wprobe_data->tw =3D tw; + wprobe_data->clear =3D clear; + wprobe_data->file =3D file; + + attr =3D &wprobe_data->attr; + hw_breakpoint_init(attr); + attr->bp_type =3D tw->type; + attr->bp_addr =3D WPROBE_DEFAULT_CLEAR_ADDRESS; + attr->bp_len =3D tw->len; + + raw_spin_lock_init(&wprobe_data->lock); + INIT_WORK(&wprobe_data->work, wprobe_work_func); + + return wprobe_data; +} + +static void wprobe_trigger_free(struct event_trigger_data *data) +{ + struct wprobe_trigger_data *wprobe_data =3D data->private_data; + + if (WARN_ON_ONCE(data->ref <=3D 0)) + return; + + data->ref--; + if (!data->ref) { + /* Remove the SOFT_MODE flag */ + trace_event_enable_disable(wprobe_data->file, 0, 1); + trace_event_put_ref(wprobe_data->file->event_call); + trigger_data_free(data); + free_wprobe_trigger_data(wprobe_data); + } +} + +static int wprobe_trigger_cmd_parse(struct event_command *cmd_ops, + struct trace_event_file *file, + char *glob, char *cmd, + char *param_and_filter) +{ + /* + * set_wprobe:EVENT:FIELD[+OFFS] + * clear_wprobe:EVENT[:FIELD[+OFFS]] + */ + struct wprobe_trigger_data *wprobe_data __free(free_wprobe_trigger_data) = =3D NULL; + struct event_trigger_data *trigger_data __free(kfree) =3D NULL; + struct ftrace_event_field *field =3D NULL; + struct trace_event_file *wprobe_file; + struct trace_array *tr =3D file->tr; + struct trace_event_call *event; + struct perf_event_attr *attr; + char *event_str, *field_str; + bool remove, clear =3D false; + struct trace_wprobe *tw; + char *param, *filter; + int ret; + + remove =3D event_trigger_check_remove(glob); + + if (!strcmp(cmd, CLEAR_WPROBE_STR)) + clear =3D true; + + if (event_trigger_empty_param(param_and_filter)) + return -EINVAL; + + ret =3D event_trigger_separate_filter(param_and_filter, ¶m, &filter, = true); + if (ret) + return ret; + + event_str =3D strsep(¶m, ":"); + + /* Find target wprobe */ + tw =3D find_trace_wprobe(event_str, WPROBE_EVENT_SYSTEM); + if (!tw) + return -ENOENT; + /* The target wprobe must not be used (unless clear) */ + if (!remove && !clear && trace_probe_is_enabled(&tw->tp)) + return -EBUSY; + + wprobe_file =3D find_event_file(tr, WPROBE_EVENT_SYSTEM, event_str); + if (!wprobe_file) + return -EINVAL; + + wprobe_data =3D wprobe_trigger_alloc(tw, wprobe_file, clear); + if (!wprobe_data) + return -ENOMEM; + attr =3D &wprobe_data->attr; + + /* Find target field, which must be equivarent to "void *" */ + field_str =3D strsep(¶m, ":"); + /* trigger removing or clear_wprobe does not need field. */ + if (!remove && !clear && !field_str) + return -EINVAL; + + if (field_str) { + char *offs; + + offs =3D strpbrk(field_str, "+-"); + if (offs) { + long val; + + if (kstrtol(offs, 0, &val) < 0) + return -EINVAL; + wprobe_data->adjust =3D val; + *offs =3D '\0'; + } + + event =3D file->event_call; + field =3D trace_find_event_field(event, field_str); + if (!field) + return -ENOENT; + + if (field->size !=3D sizeof(void *)) + return -ENOEXEC; + wprobe_data->offset =3D field->offset; + wprobe_data->field =3D kstrdup(field_str, GFP_KERNEL); + if (!wprobe_data->field) + return -ENOMEM; + } + + trigger_data =3D trigger_data_alloc(cmd_ops, cmd, param, wprobe_data); + if (!trigger_data) + return -ENOMEM; + + /* Up the trigger_data count to make sure nothing frees it on failure */ + event_trigger_init(trigger_data); + + if (remove) { + event_trigger_unregister(cmd_ops, file, glob+1, trigger_data); + return 0; + } + + ret =3D event_trigger_parse_num(param, trigger_data); + if (ret) + return ret; + + ret =3D event_trigger_set_filter(cmd_ops, file, filter, trigger_data); + if (ret < 0) + return ret; + + /* Soft-enable (register) wprobe event on WPROBE_DEFAULT_CLEAR_ADDRESS */ + tw->addr =3D attr->bp_addr =3D WPROBE_DEFAULT_CLEAR_ADDRESS; + ret =3D trace_event_enable_disable(wprobe_file, 1, 1); + if (ret < 0) { + event_trigger_reset_filter(cmd_ops, trigger_data); + return ret; + } + ret =3D event_trigger_register(cmd_ops, file, glob, trigger_data); + if (ret) { + event_trigger_reset_filter(cmd_ops, trigger_data); + trace_event_enable_disable(wprobe_file, 0, 1); + return ret; + } + /* Make it NULL to avoid freeing trigger_data and wprobe_data by __free()= */ + trigger_data =3D NULL; + wprobe_data =3D NULL; + + return 0; +} + +/* Return event_trigger_data if there is a trigger which points the same w= probe */ +static struct event_trigger_data * +wprobe_trigger_find_same(struct event_trigger_data *test, + struct trace_event_file *file) +{ + struct wprobe_trigger_data *test_wprobe_data =3D test->private_data; + struct wprobe_trigger_data *wprobe_data; + struct event_trigger_data *iter; + + list_for_each_entry(iter, &file->triggers, list) { + wprobe_data =3D iter->private_data; + if (!wprobe_data || + iter->cmd_ops->trigger_type !=3D + test->cmd_ops->trigger_type) + continue; + if (wprobe_data->tw =3D=3D test_wprobe_data->tw) + return iter; + } + return NULL; +} + +static int wprobe_register_trigger(char *glob, + struct event_trigger_data *data, + struct trace_event_file *file) +{ + int ret =3D 0; + + lockdep_assert_held(&event_mutex); + + /* The same wprobe is not accept on the same file (event) */ + if (wprobe_trigger_find_same(data, file)) + return -EEXIST; + + if (data->cmd_ops->init) { + ret =3D data->cmd_ops->init(data); + if (ret < 0) + return ret; + } + + list_add_rcu(&data->list, &file->triggers); + + update_cond_flag(file); + ret =3D trace_event_trigger_enable_disable(file, 1); + if (ret < 0) { + list_del_rcu(&data->list); + update_cond_flag(file); + } + return ret; +} + +static void wprobe_unregister_trigger(char *glob, + struct event_trigger_data *test, + struct trace_event_file *file) +{ + struct event_trigger_data *data; + + lockdep_assert_held(&event_mutex); + + data =3D wprobe_trigger_find_same(test, file); + if (!data) + return; + + list_del_rcu(&data->list); + trace_event_trigger_enable_disable(file, 0); + update_cond_flag(file); + if (data->cmd_ops->free) + data->cmd_ops->free(data); +} + +static struct event_command trigger_wprobe_set_cmd =3D { + .name =3D SET_WPROBE_STR, + .trigger_type =3D ETT_EVENT_WPROBE, + /* This triggers after when the event is recorded. */ + .flags =3D EVENT_CMD_FL_NEEDS_REC, + .parse =3D wprobe_trigger_cmd_parse, + .reg =3D wprobe_register_trigger, + .unreg =3D wprobe_unregister_trigger, + .set_filter =3D set_trigger_filter, + .trigger =3D wprobe_trigger, + .count_func =3D event_trigger_count, + .print =3D wprobe_trigger_print, + .init =3D event_trigger_init, + .free =3D wprobe_trigger_free, +}; + +static struct event_command trigger_wprobe_clear_cmd =3D { + .name =3D CLEAR_WPROBE_STR, + .trigger_type =3D ETT_EVENT_WPROBE, + /* This triggers after when the event is recorded. */ + .flags =3D EVENT_CMD_FL_NEEDS_REC, + .parse =3D wprobe_trigger_cmd_parse, + .reg =3D wprobe_register_trigger, + .unreg =3D wprobe_unregister_trigger, + .set_filter =3D set_trigger_filter, + .trigger =3D wprobe_trigger, + .count_func =3D event_trigger_count, + .print =3D wprobe_trigger_print, + .init =3D event_trigger_init, + .free =3D wprobe_trigger_free, +}; + +static __init int init_trigger_wprobe_cmds(void) +{ + int ret; + + ret =3D register_event_command(&trigger_wprobe_set_cmd); + if (WARN_ON(ret < 0)) + return ret; + ret =3D register_event_command(&trigger_wprobe_clear_cmd); + if (WARN_ON(ret < 0)) + unregister_event_command(&trigger_wprobe_set_cmd); + + if (!ret) + wprobe_trigger_global_enabled =3D 1; + + return ret; +} +fs_initcall(init_trigger_wprobe_cmds); +#endif /* CONFIG_WPROBE_TRIGGERS */ From nobody Sat Feb 7 15:22:00 2026 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id AD26823BCF7; Wed, 28 Jan 2026 14:11:08 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769609468; cv=none; b=HEOjLsmrGC4vFuruEhI/raFZ8uWKYHkf/uFeDIpHzg7AXKZ6jeiNpEJJWazqC08qP5tqWAZRkJgB1oIwshb/sVpAtSAq28fn9owF+WMHCiwxK9uooKQWyH7HHNOzxeiHBzs5A1JZHPyh6MKwwnqVW67jwcQ5Ir5LriF92DuDIbw= ARC-Message-Signature: i=1; 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b=Do9ekvyPPRR+MUe8JFC7mtz4WDI25l3g4kCbWKpqWUTxN1BN1l6tGaoNfnJnddSHQ nVoREhI0BQvBJDNo9y8GVTtIouS9Bc/M/M8b1/zhqn+4+1HWj67MirSljh/Fizk4y5 xU0fukBPOVxK8Kje/Yb2q6MliloylkKMf4ndeXu+m2JXMfrcwRiLuhcVQjskXNJqkF ILfkK0zNTvREJVMZFx3WosFcSUOAOJ042vrL4uBaZfc9/2FMyxBLsTxXAiANqmCjzN XHXs5oeKYQoUymM3BDusLWmdMwaB1wiaz6bnFgMretADIfW2pxU2XFrp+Pvy9MjFcj snNBDQqkz5tvg== From: "Masami Hiramatsu (Google)" To: Steven Rostedt , Peter Zijlstra , Ingo Molnar , x86@kernel.org Cc: Jinchao Wang , Mathieu Desnoyers , Masami Hiramatsu , Thomas Gleixner , Borislav Petkov , Dave Hansen , "H . Peter Anvin" , Alexander Shishkin , Ian Rogers , linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-perf-users@vger.kernel.org Subject: [PATCH v6 11/11] selftests: ftrace: Add wprobe trigger testcase Date: Wed, 28 Jan 2026 23:11:02 +0900 Message-ID: <176960946223.182525.2450061066358568551.stgit@devnote2> X-Mailer: git-send-email 2.43.0 In-Reply-To: <176960933881.182525.11984731584313026309.stgit@devnote2> References: <176960933881.182525.11984731584313026309.stgit@devnote2> User-Agent: StGit/0.19 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable From: Masami Hiramatsu (Google) Add a testcase for checking wprobe trigger. This sets set_wprobe and clear_wprobe triggers on fprobe events to watch dentry access. So this depends on both wprobe and fprobe. Signed-off-by: Masami Hiramatsu (Google) --- Changes in v5: - Enable CONFIG_WPROBE_TRIGGERS in the config for ftrace test. Changes in v3: - Newly added. --- tools/testing/selftests/ftrace/config | 1=20 .../ftrace/test.d/trigger/trigger-wprobe.tc | 48 ++++++++++++++++= ++++ 2 files changed, 49 insertions(+) create mode 100644 tools/testing/selftests/ftrace/test.d/trigger/trigger-w= probe.tc diff --git a/tools/testing/selftests/ftrace/config b/tools/testing/selftest= s/ftrace/config index d2f503722020..ecdee77f360f 100644 --- a/tools/testing/selftests/ftrace/config +++ b/tools/testing/selftests/ftrace/config @@ -28,3 +28,4 @@ CONFIG_TRACER_SNAPSHOT=3Dy CONFIG_UPROBES=3Dy CONFIG_UPROBE_EVENTS=3Dy CONFIG_WPROBE_EVENTS=3Dy +CONFIG_WPROBE_TRIGGERS=3Dy diff --git a/tools/testing/selftests/ftrace/test.d/trigger/trigger-wprobe.t= c b/tools/testing/selftests/ftrace/test.d/trigger/trigger-wprobe.tc new file mode 100644 index 000000000000..a012f7b92405 --- /dev/null +++ b/tools/testing/selftests/ftrace/test.d/trigger/trigger-wprobe.tc @@ -0,0 +1,48 @@ +#!/bin/sh +# SPDX-License-Identifier: GPL-2.0 +# description: event trigger - test wprobe trigger +# requires: dynamic_events "w[:[/][]] [r|w|rw]@[:= ]":README events/sched/sched_process_fork/trigger + +echo 0 > tracing_on + +:;: "Add a wprobe event used by trigger" ;: +echo 'w:watch rw@0:8 address=3D$addr value=3D+0($addr)' > dynamic_events + +:;: "Add events for triggering wprobe" ;: +echo 'f:truncate do_truncate dentry=3D$arg2' >> dynamic_events +echo 'f:dentry_kill __dentry_kill dentry=3D$arg1' >> dynamic_events + +:;: "Add wprobe triggers" ;: +echo 'set_wprobe:watch:dentry' >> events/fprobes/truncate/trigger +echo 'clear_wprobe:watch:dentry' >> events/fprobes/dentry_kill/trigger +cat events/fprobes/truncate/trigger | grep ^set_wprobe +cat events/fprobes/dentry_kill/trigger | grep ^clear_wprobe + +:;: "Ensure wprobe is still disabled" ;: +cat events/wprobes/watch/enable | grep 0 + +:;: "Enable events for triggers" ;: +echo 1 >> events/fprobes/truncate/enable +echo 1 >> events/fprobes/dentry_kill/enable + +:;: "Start test workload" ;: +echo 1 >> tracing_on + +echo aaa > /tmp/hoge +echo bbb > /tmp/hoge +echo ccc > /tmp/hoge +rm /tmp/hoge + +:;: "Check trace results" ;: +cat trace | grep watch + +:;: "Ensure wprobe becomes disabled again" ;: +cat events/wprobes/watch/enable | grep 0 + +:;: "Remove wprobe triggers" ;: +echo '!set_wprobe:watch:dentry' >> events/fprobes/truncate/trigger +echo '!clear_wprobe:watch' >> events/fprobes/dentry_kill/trigger +! grep ^set_wprobe events/fprobes/truncate/trigger +! grep ^clear_wprobe events/fprobes/dentry_kill/trigger + +exit 0 \ No newline at end of file