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authorAlexander Gordeev <agordeev@redhat.com>2012-03-09 14:59:59 +0100
committerThomas Gleixner <tglx@linutronix.de>2012-03-09 17:19:09 +0100
commit5234ffb9f74cfa8993d174782bc861dd9b7b5bfb (patch)
treec3933cd6177cde81a99f0bcdadb333b1233e007d /kernel/irq/handle.c
parent05d74efa3c72a5c40b0edeb15856c0230126313b (diff)
downloadlinux-stericsson-5234ffb9f74cfa8993d174782bc861dd9b7b5bfb.tar.gz
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 <oleg@redhat.com> Signed-off-by: Alexander Gordeev <agordeev@redhat.com> Link: http://lkml.kernel.org/r/20120309135958.GD2114@dhcp-26-207.brq.redhat.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'kernel/irq/handle.c')
-rw-r--r--kernel/irq/handle.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/irq/handle.c b/kernel/irq/handle.c
index 470d08c82bbe..500aaf67c546 100644
--- a/kernel/irq/handle.c
+++ b/kernel/irq/handle.c
@@ -60,7 +60,7 @@ static void irq_wake_thread(struct irq_desc *desc, struct irqaction *action)
* device interrupt, so no irq storm is lurking. If the
* RUNTHREAD bit is already set, nothing to do.
*/
- if (test_bit(IRQTF_DIED, &action->thread_flags) ||
+ if ((action->thread->flags & PF_EXITING) ||
test_and_set_bit(IRQTF_RUNTHREAD, &action->thread_flags))
return;