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Peter Anvin" , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Valentin Schneider , Arnaldo Carvalho de Melo , Namhyung Kim , Mark Rutland , Alexander Shishkin , Jiri Olsa , Ian Rogers , Adrian Hunter , "Liang, Kan" , David Hildenbrand , Lorenzo Stoakes , "Liam R. Howlett" , Vlastimil Babka , Suren Baghdasaryan , Michal Hocko , Nathan Chancellor , Nick Desaulniers , Bill Wendling , Justin Stitt , Kees Cook , Alice Ryhl , Sami Tolvanen , Miguel Ojeda , Masahiro Yamada , Rong Xu , Naveen N Rao , David Kaplan , Andrii Nakryiko , Jinjie Ruan , Nam Cao , workflows@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, linux-mm@kvack.org, llvm@lists.linux.dev, Andrey Ryabinin , Andrey Konovalov , Dmitry Vyukov , Vincenzo Frascino , kasan-dev@googlegroups.com, "David S. Miller" , Mathieu Desnoyers , linux-trace-kernel@vger.kernel.org Cc: Jinchao Wang Subject: [PATCH v4 07/21] mm/ksw: add HWBP pre-allocation Date: Fri, 12 Sep 2025 18:11:17 +0800 Message-ID: <20250912101145.465708-8-wangjinchao600@gmail.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20250912101145.465708-1-wangjinchao600@gmail.com> References: <20250912101145.465708-1-wangjinchao600@gmail.com> 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" Pre-allocate per-CPU hardware breakpoints at init with a place holder address, which will be retargeted dynamically in kprobe handler. This avoids allocation in atomic context. Signed-off-by: Jinchao Wang --- mm/kstackwatch/kstackwatch.h | 4 +++ mm/kstackwatch/watch.c | 55 ++++++++++++++++++++++++++++++++++++ 2 files changed, 59 insertions(+) diff --git a/mm/kstackwatch/kstackwatch.h b/mm/kstackwatch/kstackwatch.h index 277b192f80fa..3ea191370970 100644 --- a/mm/kstackwatch/kstackwatch.h +++ b/mm/kstackwatch/kstackwatch.h @@ -38,4 +38,8 @@ struct ksw_config { // singleton, only modified in kernel.c const struct ksw_config *ksw_get_config(void); =20 +/* watch management */ +int ksw_watch_init(void); +void ksw_watch_exit(void); + #endif /* _KSTACKWATCH_H */ diff --git a/mm/kstackwatch/watch.c b/mm/kstackwatch/watch.c index cec594032515..d3399ac840b2 100644 --- a/mm/kstackwatch/watch.c +++ b/mm/kstackwatch/watch.c @@ -1 +1,56 @@ // SPDX-License-Identifier: GPL-2.0 +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include +#include +#include + +#include "kstackwatch.h" + +static struct perf_event *__percpu *watch_events; + +static unsigned long watch_holder; + +static struct perf_event_attr watch_attr; + +bool panic_on_catch; +module_param(panic_on_catch, bool, 0644); +MODULE_PARM_DESC(panic_on_catch, "panic immediately on corruption catch"); +static void ksw_watch_handler(struct perf_event *bp, + struct perf_sample_data *data, + struct pt_regs *regs) +{ + pr_err("=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D KStackWatch: Caught stack corrupti= on =3D=3D=3D=3D=3D=3D=3D\n"); + pr_err("config %s\n", ksw_get_config()->config_str); + dump_stack(); + pr_err("=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D KStackW= atch End =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D\n"); + + if (panic_on_catch) + panic("Stack corruption detected"); +} + +int ksw_watch_init(void) +{ + int ret; + + hw_breakpoint_init(&watch_attr); + watch_attr.bp_addr =3D (unsigned long)&watch_holder; + watch_attr.bp_len =3D sizeof(watch_holder); + watch_attr.bp_type =3D HW_BREAKPOINT_W; + watch_events =3D register_wide_hw_breakpoint(&watch_attr, + ksw_watch_handler, + NULL); + if (IS_ERR(watch_events)) { + ret =3D PTR_ERR(watch_events); + pr_err("failed to register wide hw breakpoint: %d\n", ret); + return ret; + } + + return 0; +} + +void ksw_watch_exit(void) +{ + unregister_wide_hw_breakpoint(watch_events); + watch_events =3D NULL; +} --=20 2.43.0