diff options
| author | Ido Yariv <ido@wizery.com> | 2011-12-01 13:55:08 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2011-12-09 09:21:50 -0800 |
| commit | 2a96fb69ba383c2d3923456d1e933ba4950eb4c5 (patch) | |
| tree | 9b36b48f3a79e70419485ba36dfe292a48700006 | |
| parent | b669d5d9173f5f8d0e84744bc03e19d7f94f36ed (diff) | |
genirq: Fix race condition when stopping the irq thread
commit 550acb19269d65f32e9ac4ddb26c2b2070e37f1c upstream.
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.
[ tglx: Simplified it a bit ]
Signed-off-by: Ido Yariv <ido@wizery.com>
Link: http://lkml.kernel.org/r/1322740508-22640-1-git-send-email-ido@wizery.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
| -rw-r--r-- | kernel/irq/manage.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c index d40ecd5822e7..315705ca00f3 100644 --- a/kernel/irq/manage.c +++ b/kernel/irq/manage.c @@ -475,8 +475,9 @@ static irqreturn_t irq_nested_primary_handler(int irq, void *dev_id) static int irq_wait_for_interrupt(struct irqaction *action) { + set_current_state(TASK_INTERRUPTIBLE); + while (!kthread_should_stop()) { - set_current_state(TASK_INTERRUPTIBLE); if (test_and_clear_bit(IRQTF_RUNTHREAD, &action->thread_flags)) { @@ -484,7 +485,9 @@ static int irq_wait_for_interrupt(struct irqaction *action) return 0; } schedule(); + set_current_state(TASK_INTERRUPTIBLE); } + __set_current_state(TASK_RUNNING); return -1; } |