The patch titled
softlockup: fix task state setting
has been added to the -mm tree. Its filename is
kthread-synchronization-issues.patch
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------------------------------------------------------
Subject: softlockup: fix task state setting
From: Dmitry Adamushko <dmitry.adamushko@xxxxxxxxx>
kthread_stop() can be called when a 'watchdog' thread is executing after
kthread_should_stop() but before set_task_state(TASK_INTERRUPTIBLE).
Signed-off-by: Dmitry Adamushko <dmitry.adamushko@xxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxx>
Cc: Nick Piggin <nickpiggin@xxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxx>
Cc: Rusty Russell <rusty@xxxxxxxxxxxxxxx>
Cc: "Paul E. McKenney" <paulmck@xxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Cc: Andy Whitcroft <apw@xxxxxxxxxxxx>
Cc: Oleg Nesterov <oleg@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
kernel/softlockup.c | 9 ++++-----
1 file changed, 4 insertions(+), 5 deletions(-)
diff -puN kernel/softlockup.c~kthread-synchronization-issues kernel/softlockup.c
--- a/kernel/softlockup.c~kthread-synchronization-issues
+++ a/kernel/softlockup.c
@@ -216,26 +216,25 @@ static int watchdog(void *__bind_cpu)
/* initialize timestamp */
touch_softlockup_watchdog();
+ set_current_state(TASK_INTERRUPTIBLE);
/*
* Run briefly once per second to reset the softlockup timestamp.
* If this gets delayed for more than 60 seconds then the
* debug-printout triggers in softlockup_tick().
*/
while (!kthread_should_stop()) {
- set_current_state(TASK_INTERRUPTIBLE);
touch_softlockup_watchdog();
schedule();
if (kthread_should_stop())
break;
- if (this_cpu != check_cpu)
- continue;
-
- if (sysctl_hung_task_timeout_secs)
+ if (this_cpu == check_cpu && sysctl_hung_task_timeout_secs)
check_hung_uninterruptible_tasks(this_cpu);
+ set_current_state(TASK_INTERRUPTIBLE);
}
+ __set_current_state(TASK_RUNNING);
return 0;
}
_
Patches currently in -mm which might be from dmitry.adamushko@xxxxxxxxx are
kthread-synchronization-issues.patch
kthread-add-a-missing-memory-barrier-to-kthread_stop.patch
kthread-call-wake_up_process-without-the-lock-being-held.patch
-
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