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-rw-r--r--kernel/power/process.c11
1 files changed, 11 insertions, 0 deletions
diff --git a/kernel/power/process.c b/kernel/power/process.c
index fc0df8486449..06ec8869dbf1 100644
--- a/kernel/power/process.c
+++ b/kernel/power/process.c
@@ -109,6 +109,8 @@ static int try_to_freeze_tasks(bool user_only)
/**
* freeze_processes - Signal user space processes to enter the refrigerator.
+ * The current thread will not be frozen. The same process that calls
+ * freeze_processes must later call thaw_processes.
*
* On success, returns 0. On failure, -errno and system is fully thawed.
*/
@@ -120,6 +122,9 @@ int freeze_processes(void)
if (error)
return error;
+ /* Make sure this task doesn't get frozen */
+ current->flags |= PF_SUSPEND_TASK;
+
if (!pm_freezing)
atomic_inc(&system_freezing_cnt);
@@ -168,6 +173,7 @@ int freeze_kernel_threads(void)
void thaw_processes(void)
{
struct task_struct *g, *p;
+ struct task_struct *curr = current;
if (pm_freezing)
atomic_dec(&system_freezing_cnt);
@@ -182,10 +188,15 @@ void thaw_processes(void)
read_lock(&tasklist_lock);
do_each_thread(g, p) {
+ /* No other threads should have PF_SUSPEND_TASK set */
+ WARN_ON((p != curr) && (p->flags & PF_SUSPEND_TASK));
__thaw_task(p);
} while_each_thread(g, p);
read_unlock(&tasklist_lock);
+ WARN_ON(!(curr->flags & PF_SUSPEND_TASK));
+ curr->flags &= ~PF_SUSPEND_TASK;
+
usermodehelper_enable();
schedule();