diff options
| author | Ido Yariv <ido@wizery.com> | 2011-12-01 15:55:08 +0400 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2011-12-02 14:54:24 +0400 |
| commit | 550acb19269d65f32e9ac4ddb26c2b2070e37f1c (patch) | |
| tree | 804925b363142e47a4a26f1afcfb8f9e302bed0e /kernel/irq | |
| parent | b930c26416c4ea6855726fd977145ccea9afbdda (diff) | |
| download | linux-550acb19269d65f32e9ac4ddb26c2b2070e37f1c.tar.xz | |
genirq: Fix race condition when stopping the irq thread
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>
Cc: stable@kernel.org
Diffstat (limited to 'kernel/irq')
| -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 0e2b179bc7b3..1da999f5e746 100644 --- a/kernel/irq/manage.c +++ b/kernel/irq/manage.c @@ -623,8 +623,9 @@ 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)) { @@ -632,7 +633,9 @@ static int irq_wait_for_interrupt(struct irqaction *action) return 0; } schedule(); + set_current_state(TASK_INTERRUPTIBLE); } + __set_current_state(TASK_RUNNING); return -1; } |