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.
[akpm@linux-foundation.org: export debug_check_no_locks_held]
Signed-off-by: Mandeep Singh Baines <msb@chromium.org>
Cc: Ben Chan <benchan@chromium.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Rafael J. Wysocki <rjw@sisk.pl>
Cc: Ingo Molnar <mingo@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/linux/debug_locks.h b/include/linux/debug_locks.h
index 3bd46f7..a975de1 100644
--- a/include/linux/debug_locks.h
+++ b/include/linux/debug_locks.h
@@ -51,7 +51,7 @@
extern void debug_show_all_locks(void);
extern void debug_show_held_locks(struct task_struct *task);
extern void debug_check_no_locks_freed(const void *from, unsigned long len);
-extern void debug_check_no_locks_held(struct task_struct *task);
+extern void debug_check_no_locks_held(void);
#else
static inline void debug_show_all_locks(void)
{
@@ -67,7 +67,7 @@
}
static inline void
-debug_check_no_locks_held(struct task_struct *task)
+debug_check_no_locks_held(void)
{
}
#endif
diff --git a/include/linux/freezer.h b/include/linux/freezer.h
index e70df40..043a5cf 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>
@@ -48,6 +49,8 @@
static inline bool try_to_freeze(void)
{
+ if (!(current->flags & PF_NOFREEZE))
+ debug_check_no_locks_held();
might_sleep();
if (likely(!freezing(current)))
return false;