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Mon, 18 Aug 2025 05:28:55 -0700 (PDT) From: Jinchao Wang To: akpm@linux-foundation.org Cc: mhiramat@kernel.org, naveen@kernel.org, davem@davemloft.net, linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, Jinchao Wang Subject: [RFC PATCH 12/13] mm/kstackwatch: Add debug and test functions Date: Mon, 18 Aug 2025 20:26:17 +0800 Message-ID: <20250818122720.434981-13-wangjinchao600@gmail.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20250818122720.434981-12-wangjinchao600@gmail.com> References: <20250818122720.434981-1-wangjinchao600@gmail.com> <20250818122720.434981-2-wangjinchao600@gmail.com> <20250818122720.434981-3-wangjinchao600@gmail.com> <20250818122720.434981-4-wangjinchao600@gmail.com> <20250818122720.434981-5-wangjinchao600@gmail.com> <20250818122720.434981-6-wangjinchao600@gmail.com> <20250818122720.434981-7-wangjinchao600@gmail.com> <20250818122720.434981-8-wangjinchao600@gmail.com> <20250818122720.434981-9-wangjinchao600@gmail.com> <20250818122720.434981-10-wangjinchao600@gmail.com> <20250818122720.434981-11-wangjinchao600@gmail.com> <20250818122720.434981-12-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: 8bit This patch adds new helper functions to the kstackwatch module to aid in debugging and testing. - `ksw_watch_show()`: Displays information about the currently active hardware breakpoint, such as its address and length. This is useful for verifying that a breakpoint has been correctly installed. - `ksw_watch_fire()`: Manually triggers the active hardware breakpoint. This function is for testing the breakpoint handler to ensure it correctly identifies and reports the stack corruption. Signed-off-by: Jinchao Wang --- mm/kstackwatch/kstackwatch.h | 4 ++++ mm/kstackwatch/watch.c | 20 ++++++++++++++++++++ 2 files changed, 24 insertions(+) diff --git a/mm/kstackwatch/kstackwatch.h b/mm/kstackwatch/kstackwatch.h index c24a651977c0..27c71a9391ac 100644 --- a/mm/kstackwatch/kstackwatch.h +++ b/mm/kstackwatch/kstackwatch.h @@ -2,6 +2,8 @@ #ifndef _KSTACKWATCH_H #define _KSTACKWATCH_H +#include +#include #include #define MAX_FUNC_NAME_LEN 64 @@ -48,5 +50,7 @@ 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 1b4cf5d42db9..28ea24e4ae3a 100644 --- a/mm/kstackwatch/watch.c +++ b/mm/kstackwatch/watch.c @@ -218,3 +218,23 @@ void ksw_watch_off(void) ksw_watch_on((unsigned long)&marker, sizeof(marker)); pr_info("KSW: All HWBPs disarmed\n"); } + +/* Debug functions */ +void ksw_watch_show(void) +{ + struct perf_event *bp; + + bp = *this_cpu_ptr(watch_events); + pr_info("KSW: HWBP info test - bp_addr: 0x%px len:%llu\n", + (void *)bp->attr.bp_addr, bp->attr.bp_len); +} + +void ksw_watch_fire(void) +{ + struct perf_event *bp; + char *ptr; + + bp = *this_cpu_ptr(watch_events); + ptr = (char *)READ_ONCE(bp->attr.bp_addr); + *ptr = 0x42; // This should trigger immediately +} -- 2.43.0