The patch titled
worker_thread: fix racy try_to_freeze() usage
has been removed from the -mm tree. Its filename was
worker_thread-fix-racy-try_to_freeze-usage.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
Subject: worker_thread: fix racy try_to_freeze() usage
From: Oleg Nesterov <oleg@xxxxxxxxxx>
worker_thread() can miss freeze_process()->signal_wake_up() if it happens
between try_to_freeze() and prepare_to_wait(). We should check freezing()
before entering schedule().
This race was introduced by me in
[PATCH 1/1] workqueue: don't migrate pending works from the dead CPU
Looks like mm/vmscan.c:kswapd() has the same race.
Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
kernel/workqueue.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff -puN kernel/workqueue.c~worker_thread-fix-racy-try_to_freeze-usage kernel/workqueue.c
--- a/kernel/workqueue.c~worker_thread-fix-racy-try_to_freeze-usage
+++ a/kernel/workqueue.c
@@ -308,14 +308,14 @@ static int worker_thread(void *__cwq)
do_sigaction(SIGCHLD, &sa, (struct k_sigaction *)0);
for (;;) {
- if (cwq->wq->freezeable)
- try_to_freeze();
-
prepare_to_wait(&cwq->more_work, &wait, TASK_INTERRUPTIBLE);
- if (!cwq->should_stop && list_empty(&cwq->worklist))
+ if (!freezing(current) && !cwq->should_stop
+ && list_empty(&cwq->worklist))
schedule();
finish_wait(&cwq->more_work, &wait);
+ try_to_freeze();
+
if (cwq_should_stop(cwq))
break;
_
Patches currently in -mm which might be from oleg@xxxxxxxxxx are
origin.patch
freezer-read-pf_borrowed_mm-in-a-nonracy-way.patch
freezer-close-theoretical-race-between-refrigerator-and-thaw_tasks.patch
freezer-remove-pf_nofreeze-from-rcutorture-thread.patch
freezer-remove-pf_nofreeze-from-bluetooth-threads.patch
freezer-add-try_to_freeze-calls-to-all-kernel-threads.patch
freezer-fix-vfork-problem.patch
freezer-take-kernel_execve-into-consideration.patch
nlmclnt_recovery-dont-use-clone_sighand.patch
fix-kthread_create-vs-freezer-theoretical-race.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
libata-core-convert-to-use-cancel_rearming_delayed_work.patch
clone-flag-clone_parent_tidptr-leaves-invalid-results-in-memory.patch
getrusage-fill-ru_inblock-and-ru_oublock-fields-if-possible.patch
dont-init-pgrp-and-__session-in-init_signals.patch
-
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