The patch titled
freezer: fix PF_NOFREEZE vs freezeable race
has been removed from the -mm tree. Its filename was
freezer-fix-pf_nofreeze-vs-freezeable-race.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
Subject: freezer: fix PF_NOFREEZE vs 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, but it will be frozen on
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>
Signed-off-by: Rafael J. Wysocki <rjw@xxxxxxx>
Cc: Oleg Nesterov <oleg@xxxxxxxxxx>
Cc: Pavel Machek <pavel@xxxxxx>
Cc: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/freezer.h | 6 ++++--
1 files changed, 4 insertions(+), 2 deletions(-)
diff -puN include/linux/freezer.h~freezer-fix-pf_nofreeze-vs-freezeable-race include/linux/freezer.h
--- a/include/linux/freezer.h~freezer-fix-pf_nofreeze-vs-freezeable-race
+++ a/include/linux/freezer.h
@@ -63,8 +63,10 @@ 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
fix-stop_machine_run-problem-with-naughty-real-time-process.patch
cpu-hotplug-fix-ksoftirqd-termination-on-cpu-hotplug-with-naughty-realtime-process.patch
cpu-hotplug-fix-ksoftirqd-termination-on-cpu-hotplug-with-naughty-realtime-process-fix.patch
percpu_counters-use-cpu-notifiers.patch
percpu_counters-use-for_each_online_cpu.patch
-
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