Re: [PATCH] [ipc/sem.c] fix race with concurrent semtimedop()timeouts and IPC_RMID
From: Andrew Morton
Date: Thu Jul 21 2011 - 02:58:45 EST
On Thu, 21 Jul 2011 08:42:53 +0200 Manfred Spraul <manfred@xxxxxxxxxxxxxxxx> wrote:
> If a semaphore array is removed and in parallel a sleeping task is woken up
> (signal or timeout, does not matter), then the woken up task does not wait
> until wake_up_sem_queue_do() is completed. This will cause crashes, because
> wake_up_sem_queue_do() will read from a stale pointer.
> The fix is simple: Regardless of anything, always call get_queue_result().
> This function waits until wake_up_sem_queue_do() has finished it's task.
> Andrew, could you please take care of merging the patch?
yup, thanks for this. It's good to hear from you, and that you've
still got what it takes :)
Do you know how long this bug has been around for? Somewhere between
2.6.32 and 2.6.36, but that a large interval!
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