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authorMandeep Singh Baines <msb@chromium.org>2013-05-06 23:50:09 +0000
committerArve Hjønnevåg <arve@android.com>2013-07-01 15:38:05 -0700
commitee6db224513349d5bb26417e62ead8842e6b861c (patch)
tree57ab39ad16c2b61359ce181f4309e9d7747da52a
parent0f7aff8620c7f70532937a236a12ded5f28cde91 (diff)
downloadvexpress-lsk-ee6db224513349d5bb26417e62ead8842e6b861c.tar.gz
lockdep: check that no locks held at freeze time
We shouldn't try_to_freeze if locks are held. Holding a lock can cause a deadlock if the lock is later acquired in the suspend or hibernate path (e.g. by dpm). Holding a lock can also cause a deadlock in the case of cgroup_freezer if a lock is held inside a frozen cgroup that is later acquired by a process outside that group. History: This patch was originally applied as 6aa9707099c and reverted in dbf520a9d7d4 because NFS was freezing with locks held. It was deemed better to keep the bad freeze point in NFS to allow laptops to suspend consistently. The previous patch in this series converts NFS to call _unsafe versions of the freezable helpers so that lockdep doesn't complain about them until a more correct fix can be applied. Change-Id: Ib9d4299fb75a39e611b868be42e413909a994baa [akpm@linux-foundation.org: export debug_check_no_locks_held] Signed-off-by: Mandeep Singh Baines <msb@chromium.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Pavel Machek <pavel@ucw.cz> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Colin Cross <ccross@android.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
-rw-r--r--include/linux/freezer.h3
1 files changed, 3 insertions, 0 deletions
diff --git a/include/linux/freezer.h b/include/linux/freezer.h
index d3c038ec9a8..bcf9e651cc8 100644
--- a/include/linux/freezer.h
+++ b/include/linux/freezer.h
@@ -3,6 +3,7 @@
#ifndef FREEZER_H_INCLUDED
#define FREEZER_H_INCLUDED
+#include <linux/debug_locks.h>
#include <linux/sched.h>
#include <linux/wait.h>
#include <linux/atomic.h>
@@ -60,6 +61,8 @@ static inline bool try_to_freeze_unsafe(void)
static inline bool try_to_freeze(void)
{
+ if (!(current->flags & PF_NOFREEZE))
+ debug_check_no_locks_held();
return try_to_freeze_unsafe();
}