The patch titled
Fix PF_NOFREEZE and freezeable race
has been removed from the -mm tree. Its filename was
fix-pf_nofreeze-and-freezeable-race-2.patch
This patch was dropped because an updated version will be merged
------------------------------------------------------
Subject: Fix PF_NOFREEZE and freezeable race
From: Gautham R Shenoy <ego@xxxxxxxxxx>
This patch fixes the race pointed out by Oleg Nesterov.
* Freezer marks a thread as freezeable.
* The thread now marks itself PF_NOFREEZE causing it to
freeze on calling try_to_freeze(). Thus the task is frozen, even though
it doesn't want to.
* Subsequent thaw_processes() will also fail to thaw the task since it is
marked PF_NOFREEZE.
Avoid this problem by checking the task's PF_NOFREEZE status in
frozen_processes() before marking the task as frozen.
Signed-off-by: Gautham R Shenoy <ego@xxxxxxxxxx>
Cc: "Rafael J. Wysocki" <rjw@xxxxxxx>
Cc: Oleg Nesterov <oleg@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/freezer.h | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff -puN include/linux/freezer.h~fix-pf_nofreeze-and-freezeable-race-2 include/linux/freezer.h
--- a/include/linux/freezer.h~fix-pf_nofreeze-and-freezeable-race-2
+++ a/include/linux/freezer.h
@@ -57,8 +57,10 @@ static inline int thaw_process(struct ta
*/
static inline void frozen_process(struct task_struct *p)
{
- p->flags |= PF_FROZEN;
- wmb();
+ if (!unlikely(p->flags & PF_NOFREEZE)) {
+ p->flags |= PF_FROZEN;
+ wmb();
+ }
clear_tsk_thread_flag(p, TIF_FREEZE);
}
_
Patches currently in -mm which might be from ego@xxxxxxxxxx are
origin.patch
fix-pf_nofreeze-and-freezeable-race-2.patch
freezer-document-task_lock-in-thaw_process.patch
move-frozen_process-to-kernel-power-processc.patch
separate-freezer-from-pm-code-rev-2.patch
introduce-freezer-flags-rev-2.patch
-
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