From 5234ffb9f74cfa8993d174782bc861dd9b7b5bfb Mon Sep 17 00:00:00 2001 From: Alexander Gordeev Date: Fri, 9 Mar 2012 14:59:59 +0100 Subject: genirq: Get rid of unnecessary IRQTF_DIED flag Currently IRQTF_DIED flag is set when a IRQ thread handler calls do_exit() But also PF_EXITING per process flag gets set when a thread exits. This fix eliminates the duplicate by using PF_EXITING flag. Also, there is a race condition in exit_irq_thread(). In case a thread's bit is cleared in desc->threads_oneshot (and the IRQ line gets unmasked), but before IRQTF_DIED flag is set, a new interrupt might come in and set just cleared bit again, this time forever. This fix throws IRQTF_DIED flag away, eliminating the race as a result. [ tglx: Test THREAD_EXITING first as suggested by Oleg ] Reported-by: Oleg Nesterov Signed-off-by: Alexander Gordeev Link: http://lkml.kernel.org/r/20120309135958.GD2114@dhcp-26-207.brq.redhat.com Signed-off-by: Thomas Gleixner --- kernel/irq/manage.c | 11 +---------- 1 file changed, 1 insertion(+), 10 deletions(-) (limited to 'kernel/irq/manage.c') diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c index 3feab4ab6877..a94466db73b2 100644 --- a/kernel/irq/manage.c +++ b/kernel/irq/manage.c @@ -845,17 +845,8 @@ void exit_irq_thread(void) desc = irq_to_desc(action->irq); - /* - * Prevent a stale desc->threads_oneshot. Must be called - * before setting the IRQTF_DIED flag. - */ + /* Prevent a stale desc->threads_oneshot */ irq_finalize_oneshot(desc, action, true); - - /* - * Set the THREAD DIED flag to prevent further wakeups of the - * soon to be gone threaded handler. - */ - set_bit(IRQTF_DIED, &action->flags); } static void irq_setup_forced_threading(struct irqaction *new) -- cgit v1.2.3-58-ga151