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Rao" , Andrey Ryabinin , Alexander Potapenko , Andrey Konovalov , Dmitry Vyukov , Vincenzo Frascino , kasan-dev@googlegroups.com, "David S. Miller" , Steven Rostedt , Mathieu Desnoyers , Ingo Molnar , Arnaldo Carvalho de Melo , Namhyung Kim , Mark Rutland , Alexander Shishkin , Jiri Olsa , Ian Rogers , Adrian Hunter , "Liang, Kan" , Thomas Gleixner , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , linux-mm@kvack.org, linux-trace-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Jinchao Wang Subject: [PATCH v3 12/19] mm/ksw: manage start/stop of stack watching Date: Wed, 10 Sep 2025 13:31:10 +0800 Message-ID: <20250910053147.1152253-4-wangjinchao600@gmail.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20250910053147.1152253-1-wangjinchao600@gmail.com> References: <20250910052335.1151048-1-wangjinchao600@gmail.com> <20250910053147.1152253-1-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: 8bit Introduce helper functions to start and stop watching the configured function. These handle initialization/cleanup of both stack and watch components, and maintain a `watching_active` flag to track current state. Ensure procfs write triggers proper stop/start sequence, and show handler indicates watching status. Signed-off-by: Jinchao Wang --- mm/kstackwatch/kernel.c | 55 ++++++++++++++++++++++++++++++++++++++++- 1 file changed, 54 insertions(+), 1 deletion(-) diff --git a/mm/kstackwatch/kernel.c b/mm/kstackwatch/kernel.c index 8e1dca45003e..9ef969f28e29 100644 --- a/mm/kstackwatch/kernel.c +++ b/mm/kstackwatch/kernel.c @@ -17,6 +17,43 @@ MODULE_LICENSE("GPL"); static struct ksw_config *ksw_config; static atomic_t config_file_busy = ATOMIC_INIT(0); +static bool watching_active; + +static int ksw_start_watching(void) +{ + int ret; + + /* + * Watch init will preallocate the HWBP, + * so it must happen before stack init + */ + ret = ksw_watch_init(); + if (ret) { + pr_err("ksw_watch_init ret: %d\n", ret); + return ret; + } + + ret = ksw_stack_init(); + if (ret) { + pr_err("ksw_stack_init ret: %d\n", ret); + ksw_watch_exit(); + return ret; + } + watching_active = true; + + pr_info("start watching: %s\n", ksw_config->config_str); + return 0; +} + +static void ksw_stop_watching(void) +{ + ksw_stack_exit(); + ksw_watch_exit(); + watching_active = false; + + pr_info("stop watching: %s\n", ksw_config->config_str); +} + /* * Format of the configuration string: * function+ip_offset[+depth] [local_var_offset:local_var_len] @@ -109,6 +146,9 @@ static ssize_t kstackwatch_proc_write(struct file *file, if (copy_from_user(input, buffer, count)) return -EFAULT; + if (watching_active) + ksw_stop_watching(); + input[count] = '\0'; strim(input); @@ -123,12 +163,22 @@ static ssize_t kstackwatch_proc_write(struct file *file, return ret; } + ret = ksw_start_watching(); + if (ret) { + pr_err("Failed to start watching with %d\n", ret); + return ret; + } + return count; } static int kstackwatch_proc_show(struct seq_file *m, void *v) { - seq_printf(m, "%s\n", ksw_config->config_str); + if (watching_active) + seq_printf(m, "%s\n", ksw_config->config_str); + else + seq_puts(m, "not watching\n"); + return 0; } @@ -176,6 +226,9 @@ static int __init kstackwatch_init(void) static void __exit kstackwatch_exit(void) { + if (watching_active) + ksw_stop_watching(); + remove_proc_entry("kstackwatch", NULL); kfree(ksw_config); -- 2.43.0