From 0f9548ca10916dec166eaf74c816bded7d8e611d Mon Sep 17 00:00:00 2001 From: Mandeep Singh Baines Date: Mon, 6 May 2013 23:50:09 +0000 Subject: [PATCH] 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. [akpm@linux-foundation.org: export debug_check_no_locks_held] Signed-off-by: Mandeep Singh Baines Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Acked-by: Pavel Machek Acked-by: Tejun Heo Signed-off-by: Colin Cross Signed-off-by: Rafael J. Wysocki --- include/linux/freezer.h | 3 +++ 1 file changed, 3 insertions(+) diff --git a/include/linux/freezer.h b/include/linux/freezer.h index d3c038ec9a88..bcf9e651cc85 100644 --- a/include/linux/freezer.h +++ b/include/linux/freezer.h @@ -3,6 +3,7 @@ #ifndef FREEZER_H_INCLUDED #define FREEZER_H_INCLUDED +#include #include #include #include @@ -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(); } -- 2.20.1