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authorColin Cross <ccross@android.com>2013-07-24 17:41:33 -0700
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2013-07-30 14:05:06 +0200
commit2b44c4db2e2f1765d35163a861d301038e0c8a75 (patch)
treef091046e31e220b876d15b0bf713955184a8e68f /kernel/freezer.c
parent016d5baad04269e8559332df05f89bd95b52d6ad (diff)
downloadlinux-sh-2b44c4db2e2f1765d35163a861d301038e0c8a75.tar.gz
freezer: set PF_SUSPEND_TASK flag on tasks that call freeze_processes
Calling freeze_processes sets a global flag that will cause any process that calls try_to_freeze to enter the refrigerator. It skips sending a signal to the current task, but if the current task ever hits try_to_freeze, all threads will be frozen and the system will deadlock. Set a new flag, PF_SUSPEND_TASK, on the task that calls freeze_processes. The flag notifies the freezer that the thread is involved in suspend and should not be frozen. Also add a WARN_ON in thaw_processes if the caller does not have the PF_SUSPEND_TASK flag set to catch if a different task calls thaw_processes than the one that called freeze_processes, leaving a task with PF_SUSPEND_TASK permanently set on it. Threads that spawn off a task with PF_SUSPEND_TASK set (which swsusp does) will also have PF_SUSPEND_TASK set, preventing them from freezing while they are helping with suspend, but they need to be dead by the time suspend is triggered, otherwise they may run when userspace is expected to be frozen. Add a WARN_ON in thaw_processes if more than one thread has the PF_SUSPEND_TASK flag set. Reported-and-tested-by: Michael Leun <lkml20130126@newton.leun.net> Signed-off-by: Colin Cross <ccross@android.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'kernel/freezer.c')
-rw-r--r--kernel/freezer.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/freezer.c b/kernel/freezer.c
index 8b2afc1c9df0..b462fa197517 100644
--- a/kernel/freezer.c
+++ b/kernel/freezer.c
@@ -33,7 +33,7 @@ static DEFINE_SPINLOCK(freezer_lock);
*/
bool freezing_slow_path(struct task_struct *p)
{
- if (p->flags & PF_NOFREEZE)
+ if (p->flags & (PF_NOFREEZE | PF_SUSPEND_TASK))
return false;
if (pm_nosig_freezing || cgroup_freezing(p))