Allow dynamic enabling/disabling of KStackWatch through user input of proc. With this patch, the entire system becomes functional.
Signed-off-by: Jinchao Wang <[email protected]> --- 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 898ebb2966fe..57628bace365 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) */ @@ -117,8 +154,18 @@ 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, @@ -133,6 +180,9 @@ 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); @@ -147,6 +197,12 @@ 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
