Messages in this thread Patch in this message | | | Date | Fri, 31 Oct 2014 12:10:41 +0100 | From | Peter Zijlstra <> | Subject | [PATCH 4/7] audit,wait: Fixup kauditd_thread wait loop |
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The kauditd_thread wait loop is a bit iffy; it has a number of problems:
- calls try_to_freeze() before schedule(); you typically want the thread to re-evaluate the sleep condition when unfreezing, also freeze_task() issues a wakeup.
- it unconditionally does the {add,remove}_wait_queue(), even when the sleep condition is false.
Use wait_event_freezable() that does the right thing.
Cc: mingo@kernel.org Cc: oleg@redhat.com Cc: torvalds@linux-foundation.org Cc: tglx@linutronix.de Cc: Eric Paris <eparis@redhat.com> Reported-by: Mike Galbraith <umgwanakikbuti@gmail.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: http://lkml.kernel.org/r/20141002102251.GA6324@worktop.programming.kicks-ass.net --- kernel/audit.c | 11 +---------- 1 file changed, 1 insertion(+), 10 deletions(-)
--- a/kernel/audit.c +++ b/kernel/audit.c @@ -499,7 +499,6 @@ static int kauditd_thread(void *dummy) set_freezable(); while (!kthread_should_stop()) { struct sk_buff *skb; - DECLARE_WAITQUEUE(wait, current); flush_hold_queue(); @@ -514,16 +513,8 @@ static int kauditd_thread(void *dummy) audit_printk_skb(skb); continue; } - set_current_state(TASK_INTERRUPTIBLE); - add_wait_queue(&kauditd_wait, &wait); - if (!skb_queue_len(&audit_skb_queue)) { - try_to_freeze(); - schedule(); - } - - __set_current_state(TASK_RUNNING); - remove_wait_queue(&kauditd_wait, &wait); + wait_event_freezable(kauditd_wait, skb_queue_len(&audit_skb_queue)); } return 0; }
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