Messages in this thread Patch in this message | | | From | Ido Yariv <> | Subject | [PATCH] irq: Fix race condition when stopping the irq thread | Date | Thu, 1 Dec 2011 13:55:08 +0200 |
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In irq_wait_for_interrupt(), the should_stop member is verified before setting the task's state to TASK_INTERRUPTIBLE and calling schedule(). In case kthread_stop sets should_stop and wakes up the process after should_stop is checked by the irq thread but before the task's state is changed, the irq thread might never exit:
kthread_stop irq_wait_for_interrupt ------------ ----------------------
... ... while (!kthread_should_stop()) { kthread->should_stop = 1; wake_up_process(k); wait_for_completion(&kthread->exited); ... set_current_state(TASK_INTERRUPTIBLE);
...
schedule(); } ...
Fix this by checking if the thread should stop after modifying the task's state.
Signed-off-by: Ido Yariv <ido@wizery.com> Cc: stable@kernel.org --- kernel/irq/manage.c | 6 +++++- 1 files changed, 5 insertions(+), 1 deletions(-)
diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c index 0e2b179..3194d5e 100644 --- a/kernel/irq/manage.c +++ b/kernel/irq/manage.c @@ -631,7 +631,11 @@ static int irq_wait_for_interrupt(struct irqaction *action) __set_current_state(TASK_RUNNING); return 0; } - schedule(); + + if (!kthread_should_stop()) + schedule(); + else + __set_current_state(TASK_RUNNING); } return -1; } -- 1.7.7.3
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