The patch titled
hibernate: fix lockdep report
has been removed from the -mm tree. Its filename was
hibernate-fix-lockdep-report-2.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
Subject: hibernate: fix lockdep report
From: Johannes Berg <[EMAIL PROTECTED]>
Lockdep reports a circular locking dependency in the hibernate code
because
- during system boot hibernate code (from an initcall) locks pm_mutex
and then a sysfs buffer mutex via name_to_dev_t
- during regular operation hibernate code locks pm_mutex under a
sysfs buffer mutex because it's called from sysfs methods.
The deadlock can never happen because during initcall invocation nothing
can write to sysfs yet. This removes the lockdep report by marking the
initcall locking as being in a different class.
Signed-off-by: Johannes Berg <[EMAIL PROTECTED]>
Cc: "Rafael J. Wysocki" <[EMAIL PROTECTED]>
Cc: Alan Stern <[EMAIL PROTECTED]>
Acked-by: Peter Zijlstra <[EMAIL PROTECTED]>
Cc: Pavel Machek <[EMAIL PROTECTED]>
Signed-off-by: Andrew Morton <[EMAIL PROTECTED]>
---
kernel/power/disk.c | 12 +++++++++++-
1 file changed, 11 insertions(+), 1 deletion(-)
diff -puN kernel/power/disk.c~hibernate-fix-lockdep-report-2 kernel/power/disk.c
--- a/kernel/power/disk.c~hibernate-fix-lockdep-report-2
+++ a/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);
_
Patches currently in -mm which might be from [EMAIL PROTECTED] are
origin.patch
git-kbuild.patch
git-wireless.patch
-
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