Commit-ID: 84b277af44cadb263d8d588b0c0b7d5d85f5bc2a Gitweb: http://git.kernel.org/tip/84b277af44cadb263d8d588b0c0b7d5d85f5bc2a Author: Thomas Gleixner <tglx@xxxxxxxxxxxxx> AuthorDate: Wed, 12 Aug 2009 17:22:02 +0200 Committer: Thomas Gleixner <tglx@xxxxxxxxxxxxx> CommitDate: Wed, 12 Aug 2009 17:24:16 +0200 genirq: Prevent race between free_irq() and handle_IRQ_event() If an interrupt is freed we do not check whether the interrupt is in progress when we remove the action from the action chain. With threaded handlers this can race against wake_up_process(action->thread) in handle_IRQ_event and wake_up_process() might dereference a NULL pointer. Check action->thread before we call wake_up_process() LKML-Reference: <new-submission> Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx> --- kernel/irq/handle.c | 10 +++++++++- 1 files changed, 9 insertions(+), 1 deletions(-) diff --git a/kernel/irq/handle.c b/kernel/irq/handle.c index 065205b..4e7f17a 100644 --- a/kernel/irq/handle.c +++ b/kernel/irq/handle.c @@ -403,8 +403,16 @@ irqreturn_t handle_IRQ_event(unsigned int irq, struct irqaction *action) */ if (likely(!test_bit(IRQTF_DIED, &action->thread_flags))) { + struct task_struct *tsk = action->thread; + set_bit(IRQTF_RUNTHREAD, &action->thread_flags); - wake_up_process(action->thread); + /* + * Check tsk as we might race against + * free_irq which sets action->thread + * to NULL + */ + if (tsk) + wake_up_process(tsk); } /* Fall through to add to randomness */ -- To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html