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Miller" , Dietmar Eggemann , Dmitry Vyukov , "H. Peter Anvin" , Ian Rogers , Ingo Molnar , James Clark , Jinchao Wang , Jinjie Ruan , Jiri Olsa , Jonathan Corbet , Juri Lelli , Justin Stitt , kasan-dev@googlegroups.com, Kees Cook , "Liam R. Howlett" , "Liang Kan" , Linus Walleij , linux-arm-kernel@lists.infradead.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-perf-users@vger.kernel.org, linux-trace-kernel@vger.kernel.org, llvm@lists.linux.dev, Lorenzo Stoakes , Mark Rutland , Masahiro Yamada , Mathieu Desnoyers , Mel Gorman , Michal Hocko , Miguel Ojeda , Nam Cao , Namhyung Kim , Nathan Chancellor , Naveen N Rao , Nick Desaulniers , Rong Xu , Sami Tolvanen , Steven Rostedt , Suren Baghdasaryan , Thomas Gleixner , =?UTF-8?q?Thomas=20Wei=C3=9Fschuh?= , Valentin Schneider , Vincent Guittot , Vincenzo Frascino , Vlastimil Babka , Will Deacon , workflows@vger.kernel.org, x86@kernel.org Subject: [PATCH v8 16/27] mm/ksw: manage probe and HWBP lifecycle via procfs Date: Tue, 11 Nov 2025 00:36:11 +0800 Message-ID: <20251110163634.3686676-17-wangjinchao600@gmail.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20251110163634.3686676-1-wangjinchao600@gmail.com> References: <20251110163634.3686676-1-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 Allow dynamic enabling/disabling of KStackWatch through user input of proc. With this patch, the entire system becomes functional. Signed-off-by: Jinchao Wang --- mm/kstackwatch/kernel.c | 60 +++++++++++++++++++++++++++++++++++++++-- 1 file changed, 58 insertions(+), 2 deletions(-) diff --git a/mm/kstackwatch/kernel.c b/mm/kstackwatch/kernel.c index 87fef139f494..a0e676e60692 100644 --- a/mm/kstackwatch/kernel.c +++ b/mm/kstackwatch/kernel.c @@ -14,6 +14,43 @@ static struct ksw_config *ksw_config; static struct dentry *dbgfs_config; static struct dentry *dbgfs_dir; +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->user_input); + 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->user_input); +} + struct param_map { const char *name; /* long name */ const char *short_name; /* short name (2 letters) */ @@ -119,8 +156,18 @@ static int ksw_parse_config(char *buf, struct ksw_config *config) static ssize_t ksw_dbgfs_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) { - return simple_read_from_buffer(buf, count, ppos, ksw_config->user_input, - ksw_config->user_input ? strlen(ksw_config->user_input) : 0); + const char *out; + size_t len; + + if (watching_active && ksw_config->user_input) { + out = ksw_config->user_input; + len = strlen(out); + } else { + out = "not watching\n"; + len = strlen(out); + } + + return simple_read_from_buffer(buf, count, ppos, out, len); } static ssize_t ksw_dbgfs_write(struct file *file, const char __user *buffer, @@ -135,6 +182,9 @@ static ssize_t ksw_dbgfs_write(struct file *file, const char __user *buffer, if (copy_from_user(input, buffer, count)) return -EFAULT; + if (watching_active) + ksw_stop_watching(); + input[count] = '\0'; strim(input); @@ -149,6 +199,12 @@ static ssize_t ksw_dbgfs_write(struct file *file, const char __user *buffer, return ret; } + ret = ksw_start_watching(); + if (ret) { + pr_err("Failed to start watching with %d\n", ret); + return ret; + } + return count; } -- 2.43.0