Merge branch 'master' of /pub/scm/linux/kernel/git/torvalds/linux-2.6

1 files changed, 11 insertions, 1 deletions

diff --git a/kernel/power/disk.c b/kernel/power/disk.c
index 8b15f777010a..05b64790fe83 100644
--- a/kernel/power/disk.c
+++ b/kernel/power/disk.c
@@ -456,7 +456,17 @@ static int software_resume(void)
         int error;
         unsigned int flags;
 
-        mutex_lock(&pm_mutex);
+        /*
+         * name_to_dev_t() below takes a sysfs buffer mutex when sysfs
+         * is configured into the kernel. Since the regular hibernate
+         * trigger path is via sysfs which takes a buffer mutex before
+         * calling hibernate functions (which take pm_mutex) this can
+         * cause lockdep to complain about a possible ABBA deadlock
+         * which cannot happen since we're in the boot code here and
+         * sysfs can't be invoked yet. Therefore, we use a subclass
+         * here to avoid lockdep complaining.
+         */
+        mutex_lock_nested(&pm_mutex, SINGLE_DEPTH_NESTING);
         if (!swsusp_resume_device) {
                 if (!strlen(resume_file)) {
                         mutex_unlock(&pm_mutex);