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Rao" , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , Peter Zijlstra , 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 , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , linux-perf-users@vger.kernel.org, linux-mm@kvack.org, linux-trace-kernel@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Jinchao Wang Subject: [PATCH v2 12/18] mm/ksw: add self-debug functions for kstackwatch watch Date: Thu, 4 Sep 2025 08:21:09 +0800 Message-ID: <20250904002126.1514566-13-wangjinchao600@gmail.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20250904002126.1514566-1-wangjinchao600@gmail.com> References: <20250904002126.1514566-1-wangjinchao600@gmail.com> Precedence: bulk X-Mailing-List: linux-perf-users@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Introduce ksw_watch_show() and ksw_watch_fire() for runtime debugging of kstackwatch's watch mechanism: - ksw_watch_show(): prints the currently armed watch address and length - ksw_watch_fire(): forcibly triggers the watch by writing to the watched address These functions help validate the dynamic watch behavior and facilitate testing without requiring real events. Signed-off-by: Jinchao Wang --- mm/kstackwatch/kstackwatch.h | 2 ++ mm/kstackwatch/watch.c | 17 ++++++++++++++++- 2 files changed, 18 insertions(+), 1 deletion(-) diff --git a/mm/kstackwatch/kstackwatch.h b/mm/kstackwatch/kstackwatch.h index bc8664af4fa6..d1bb5ae75aae 100644 --- a/mm/kstackwatch/kstackwatch.h +++ b/mm/kstackwatch/kstackwatch.h @@ -47,5 +47,7 @@ int ksw_watch_init(struct ksw_config *config); void ksw_watch_exit(void); int ksw_watch_on(u64 watch_addr, u64 watch_len); void ksw_watch_off(void); +void ksw_watch_show(void); +void ksw_watch_fire(void); #endif /* _KSTACKWATCH_H */ diff --git a/mm/kstackwatch/watch.c b/mm/kstackwatch/watch.c index c563f8d17829..8f3f6cb9f17a 100644 --- a/mm/kstackwatch/watch.c +++ b/mm/kstackwatch/watch.c @@ -116,7 +116,6 @@ int ksw_watch_on(u64 watch_addr, u64 watch_len) ksw_watch_on_local_cpu(&watch_info); } else { call_single_data_t *csd = &per_cpu(watch_csd, cpu); - smp_call_function_single_async(cpu, csd); } } @@ -158,3 +157,19 @@ void ksw_watch_exit(void) pr_info("KSW: watch exited\n"); } + +/* self debug function */ +void ksw_watch_show(void) +{ + pr_info("KSW: watch target bp_addr: 0x%llx len:%llu\n", + watch_info.addr, watch_info.len); +} + +/* self debug function */ +void ksw_watch_fire(void) +{ + char *ptr = (char *)watch_info.addr; + + pr_warn("KSW: watch triggered immediately\n"); + *ptr = 0x42; // This should trigger immediately +} -- 2.43.0