The patch titled
freezer: fix kthread_create vs freezer theoretical race
has been added to the -mm tree. Its filename is
freezer-fix-kthread_create-vs-freezer-theoretical-race.patch
*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: freezer: fix kthread_create vs freezer theoretical race
From: Oleg Nesterov <oleg@xxxxxxxxxx>
kthread() sleeps in TASK_INTERRUPTIBLE state waiting for the first wakeup. In
theory, this wakeup may come from freeze_process()->signal_wake_up(), so the
task can disappear even before kthread_create() sets its ->comm.
Change kthread() to use TASK_UNINTERRUPTIBLE.
[akpm@xxxxxxxxxxxxxxxxxxxx: s/BUG_ON/WARN_ON+recover]
Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx>
Acked-by: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx>
Signed-off-by: Rafael J. Wysocki <rjw@xxxxxxx>
Cc: Gautham R Shenoy <ego@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
kernel/kthread.c | 7 +++++--
1 files changed, 5 insertions(+), 2 deletions(-)
diff -puN kernel/kthread.c~freezer-fix-kthread_create-vs-freezer-theoretical-race kernel/kthread.c
--- a/kernel/kthread.c~freezer-fix-kthread_create-vs-freezer-theoretical-race
+++ a/kernel/kthread.c
@@ -70,7 +70,7 @@ static int kthread(void *_create)
data = create->data;
/* OK, tell user we're spawned, wait for stop or wakeup */
- __set_current_state(TASK_INTERRUPTIBLE);
+ __set_current_state(TASK_UNINTERRUPTIBLE);
complete(&create->started);
schedule();
@@ -162,7 +162,10 @@ EXPORT_SYMBOL(kthread_create);
*/
void kthread_bind(struct task_struct *k, unsigned int cpu)
{
- BUG_ON(k->state != TASK_INTERRUPTIBLE);
+ if (k->state != TASK_UNINTERRUPTIBLE) {
+ WARN_ON(1);
+ return;
+ }
/* Must have done schedule() in kthread() before we set_task_cpu */
wait_task_inactive(k);
set_task_cpu(k, cpu);
_
Patches currently in -mm which might be from oleg@xxxxxxxxxx are
origin.patch
getrusage-fill-ru_inblock-and-ru_oublock-fields-if-possible.patch
dont-init-pgrp-and-__session-in-init_signals.patch
libata-core-convert-to-use-cancel_rearming_delayed_work.patch
nlmclnt_recovery-dont-use-clone_sighand.patch
freezer-read-pf_borrowed_mm-in-a-nonracy-way.patch
freezer-close-potential-race-between-refrigerator-and-thaw_tasks.patch
freezer-fix-vfork-problem.patch
freezer-take-kernel_execve-into-consideration.patch
freezer-fix-kthread_create-vs-freezer-theoretical-race.patch
freezer-fix-pf_nofreeze-vs-freezeable-race.patch
freezer-move-frozen_process-to-kernel-power-processc.patch
clone-flag-clone_parent_tidptr-leaves-invalid-results-in-memory.patch
use-write_trylock_irqsave-in-ptrace_attach.patch
tidy-up-usermode-helper-waiting-a-bit.patch
-
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