From: Greg Kroah-Hartman <gregkh@linuxfoundation.org> stable inclusion from linux-4.19.228 commit cf94a8a3ff3d7aa06742f1beb5166fa45ba72122 -------------------------------- commit c9d967b2ce40d71e968eb839f36c936b8a9cf1ea upstream. The buffer handling in pm_show_wakelocks() is tricky, and hopefully correct. Ensure it really is correct by using sysfs_emit_at() which handles all of the tricky string handling logic in a PAGE_SIZE buffer for us automatically as this is a sysfs file being read from. Reviewed-by: Lee Jones <lee.jones@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Yongqiang Liu <liuyongqiang13@huawei.com> Signed-off-by: Laibin Qiu <qiulaibin@huawei.com> --- kernel/power/wakelock.c | 12 ++++-------- 1 file changed, 4 insertions(+), 8 deletions(-) diff --git a/kernel/power/wakelock.c b/kernel/power/wakelock.c index 4210152e56f0..aad7c8fcb22f 100644 --- a/kernel/power/wakelock.c +++ b/kernel/power/wakelock.c @@ -39,23 +39,19 @@ ssize_t pm_show_wakelocks(char *buf, bool show_active) { struct rb_node *node; struct wakelock *wl; - char *str = buf; - char *end = buf + PAGE_SIZE; + int len = 0; mutex_lock(&wakelocks_lock); for (node = rb_first(&wakelocks_tree); node; node = rb_next(node)) { wl = rb_entry(node, struct wakelock, node); if (wl->ws.active == show_active) - str += scnprintf(str, end - str, "%s ", wl->name); + len += sysfs_emit_at(buf, len, "%s ", wl->name); } - if (str > buf) - str--; - - str += scnprintf(str, end - str, "\n"); + len += sysfs_emit_at(buf, len, "\n"); mutex_unlock(&wakelocks_lock); - return (str - buf); + return len; } #if CONFIG_PM_WAKELOCKS_LIMIT > 0 -- 2.22.0