From nobody Sat Feb 7 21:14:47 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 1089D3358CF for ; Wed, 29 Oct 2025 14:40:45 +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=1761748845; cv=none; b=XYeL3LRm9QfDaASMFCWIBUAUGK+Bq0g33VlvaTCzxO3ngvQbZ/2x3Q2+ucV/ChzYX1B/3SogmB6vQsWUwnZUl/Za1+X6yqODtn7IWoEw8ZtSZgfqhWbYLJobBwro7vevWXkwEOEXwx1wemefwumOmmPtNIjRrKE/OHF43dpZoBI= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761748845; c=relaxed/simple; bh=yo5CmuKZA3/tkEE6ni8PGvX51r42GAR+KIaPKtkB9yE=; h=Message-ID:Date:From:To:Cc:Subject:References:MIME-Version: Content-Type; b=n05sgInrTOuNEjKyW5Umgufw33kK2aWuEnj2UwmK/UReb9aL3sYqI6HIZWizdx/q5gZytsIymKHKneOEzaJ3/D5wWCY50tG7og3d3q6D2o4b6xWZmcYyasaojkNnVm/S/0ao/xNck2/t62rPP2SimiDpX/J/MdcuYV/GpXOHX1Y= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=SN6barIj; 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="SN6barIj" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E55A1C4CEF7; Wed, 29 Oct 2025 14:40:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1761748844; bh=yo5CmuKZA3/tkEE6ni8PGvX51r42GAR+KIaPKtkB9yE=; h=Date:From:To:Cc:Subject:References:From; b=SN6barIjspeVfeOccK2m8S9LgXiFv6MFQzJgDvny2FNCOsILnQauWfEQSiLrK/88B R2IN+wf9+LS8IXXU+RJ5v7Of/S9dxzsVItS3s38nXvlB9VM9hoIMKDcagVkza4f1aU MagimuyWwfLk2s0JivCdi95bnNN0enTbfVu0bOxXdU3bvn6gOkznxbaYVUcm2R14TS aKnQQD/kABungWwxIzg96PFucRr3EFvSyirr/m0n9kJHdPjbEFiM3cb425PDb6BjiH neQarq8ijVaR69TlTgWbnYU8DGcjv+9UHQwR3Fj/sOXWmLFzc1hGWXjvIl0GXuc4cC QgBTlJwyjzZNQ== Received: from rostedt by gandalf with local (Exim 4.98.2) (envelope-from ) id 1vE7Mb-0000000530C-3Hv1; Wed, 29 Oct 2025 10:41:25 -0400 Message-ID: <20251029144125.633472489@kernel.org> User-Agent: quilt/0.68 Date: Wed, 29 Oct 2025 10:40:54 -0400 From: Steven Rostedt To: linux-kernel@vger.kernel.org Cc: Masami Hiramatsu , Mark Rutland , Mathieu Desnoyers , Andrew Morton , Peter Zijlstra , Namhyung Kim , Takaya Saeki , Tom Zanussi , Thomas Gleixner , Ian Rogers , Douglas Raillard , Arnaldo Carvalho de Melo , Jiri Olsa , Adrian Hunter , Ingo Molnar Subject: [for-next][PATCH 13/13] tracing: Have persistent ring buffer print syscalls normally References: <20251029144041.475297995@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Steven Rostedt The persistent ring buffer from a previous boot has to be careful printing events as the print formats of random events can have pointers to strings and such that are not available. Ftrace static events (like the function tracer event) are stable and are printed normally. System call event formats are also stable. Allow them to be printed normally as well: Instead of: <...>-1 [005] ...1. 57.240405: sys_enter_waitid: __syscall_nr=3D= 0xf7 (247) which=3D0x1 (1) upid=3D0x499 (1177) infop=3D0x7ffd5294d690 (1407= 25988939408) options=3D0x5 (5) ru=3D0x0 (0) <...>-1 [005] ...1. 57.240433: sys_exit_waitid: __syscall_nr=3D0= xf7 (247) ret=3D0x0 (0) <...>-1 [005] ...1. 57.240437: sys_enter_rt_sigprocmask: __sysca= ll_nr=3D0xe (14) how=3D0x2 (2) nset=3D0x7ffd5294d7c0 (140725988939712) oset= =3D0x0 (0) sigsetsize=3D0x8 (8) <...>-1 [005] ...1. 57.240438: sys_exit_rt_sigprocmask: __syscal= l_nr=3D0xe (14) ret=3D0x0 (0) <...>-1 [005] ...1. 57.240442: sys_enter_close: __syscall_nr=3D0= x3 (3) fd=3D0x4 (4) <...>-1 [005] ...1. 57.240463: sys_exit_close: __syscall_nr=3D0x= 3 (3) ret=3D0x0 (0) <...>-1 [005] ...1. 57.240485: sys_enter_openat: __syscall_nr=3D= 0x101 (257) dfd=3D0xffffffffffdfff9c (-2097252) filename=3D(0xffff8b81639ca= 01c) flags=3D0x80000 (524288) mode=3D0x0 (0) __filename_val=3D/run/systemd/= reboot-param <...>-1 [005] ...1. 57.240555: sys_exit_openat: __syscall_nr=3D0= x101 (257) ret=3D0xffffffffffdffffe (-2097154) <...>-1 [005] ...1. 57.240571: sys_enter_openat: __syscall_nr=3D= 0x101 (257) dfd=3D0xffffffffffdfff9c (-2097252) filename=3D(0xffff8b81639ca= 01c) flags=3D0x80000 (524288) mode=3D0x0 (0) __filename_val=3D/run/systemd/= reboot-param <...>-1 [005] ...1. 57.240620: sys_exit_openat: __syscall_nr=3D0= x101 (257) ret=3D0xffffffffffdffffe (-2097154) <...>-1 [005] ...1. 57.240629: sys_enter_writev: __syscall_nr=3D= 0x14 (20) fd=3D0x3 (3) vec=3D0x7ffd5294ce50 (140725988937296) vlen=3D0x7 (7) <...>-1 [005] ...1. 57.242281: sys_exit_writev: __syscall_nr=3D0= x14 (20) ret=3D0x24 (36) <...>-1 [005] ...1. 57.242286: sys_enter_reboot: __syscall_nr=3D= 0xa9 (169) magic1=3D0xfee1dead (4276215469) magic2=3D0x28121969 (672274793)= cmd=3D0x1234567 (19088743) arg=3D0x0 (0) Have: <...>-1 [000] ...1. 91.446011: sys_waitid(which: 1, upid: 0x4d2,= infop: 0x7ffdccdadfd0, options: 5, ru: 0) <...>-1 [000] ...1. 91.446042: sys_waitid -> 0x0 <...>-1 [000] ...1. 91.446045: sys_rt_sigprocmask(how: 2, nset: = 0x7ffdccdae100, oset: 0, sigsetsize: 8) <...>-1 [000] ...1. 91.446047: sys_rt_sigprocmask -> 0x0 <...>-1 [000] ...1. 91.446051: sys_close(fd: 4) <...>-1 [000] ...1. 91.446073: sys_close -> 0x0 <...>-1 [000] ...1. 91.446095: sys_openat(dfd: 18446744073709551= 516, filename: 139732544945794 "/run/systemd/reboot-param", flags: O_RDONLY= |O_CLOEXEC) <...>-1 [000] ...1. 91.446165: sys_openat -> 0xfffffffffffffffe <...>-1 [000] ...1. 91.446182: sys_openat(dfd: 18446744073709551= 516, filename: 139732544945794 "/run/systemd/reboot-param", flags: O_RDONLY= |O_CLOEXEC) <...>-1 [000] ...1. 91.446233: sys_openat -> 0xfffffffffffffffe <...>-1 [000] ...1. 91.446242: sys_writev(fd: 3, vec: 0x7ffdccda= d790, vlen: 7) <...>-1 [000] ...1. 91.447877: sys_writev -> 0x24 <...>-1 [000] ...1. 91.447883: sys_reboot(magic1: 0xfee1dead, ma= gic2: 0x28121969, cmd: 0x1234567, arg: 0) Cc: Masami Hiramatsu Cc: Mark Rutland Cc: Mathieu Desnoyers Cc: Andrew Morton Cc: Peter Zijlstra Cc: Namhyung Kim Cc: Takaya Saeki Cc: Tom Zanussi Cc: Thomas Gleixner Cc: Ian Rogers Cc: Douglas Raillard Cc: Arnaldo Carvalho de Melo Cc: Jiri Olsa Cc: Adrian Hunter Cc: Ingo Molnar Link: https://lore.kernel.org/20251028231149.097404581@kernel.org Signed-off-by: Steven Rostedt (Google) --- kernel/trace/trace.c | 27 +++++++++++++++++++++++---- 1 file changed, 23 insertions(+), 4 deletions(-) diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 2aee9a3088f4..a765792d3428 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -20,6 +20,7 @@ #include #include #include +#include #include #include #include @@ -4219,6 +4220,22 @@ static void test_cpu_buff_start(struct trace_iterato= r *iter) iter->cpu); } =20 +#ifdef CONFIG_FTRACE_SYSCALLS +static bool is_syscall_event(struct trace_event *event) +{ + return (event->funcs =3D=3D &enter_syscall_print_funcs) || + (event->funcs =3D=3D &exit_syscall_print_funcs); + +} +#define syscall_buf_size CONFIG_TRACE_SYSCALL_BUF_SIZE_DEFAULT +#else +static inline bool is_syscall_event(struct trace_event *event) +{ + return false; +} +#define syscall_buf_size 0 +#endif /* CONFIG_FTRACE_SYSCALLS */ + static enum print_line_t print_trace_fmt(struct trace_iterator *iter) { struct trace_array *tr =3D iter->tr; @@ -4251,10 +4268,12 @@ static enum print_line_t print_trace_fmt(struct tra= ce_iterator *iter) * safe to use if the array has delta offsets * Force printing via the fields. */ - if ((tr->text_delta) && - event->type > __TRACE_LAST_TYPE) + if ((tr->text_delta)) { + /* ftrace and system call events are still OK */ + if ((event->type > __TRACE_LAST_TYPE) && + !is_syscall_event(event)) return print_event_fields(iter, event); - + } return event->funcs->trace(iter, sym_flags, event); } =20 @@ -11436,7 +11455,7 @@ __init static int tracer_alloc_buffers(void) =20 global_trace.flags =3D TRACE_ARRAY_FL_GLOBAL; =20 - global_trace.syscall_buf_sz =3D CONFIG_TRACE_SYSCALL_BUF_SIZE_DEFAULT; + global_trace.syscall_buf_sz =3D syscall_buf_size; =20 INIT_LIST_HEAD(&global_trace.systems); INIT_LIST_HEAD(&global_trace.events); --=20 2.51.0