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List:       linux-kernel
Subject:    Re: [Patch] shm bug introduced with pagecache in 2.3.11
From:       Alan Cox <alan () lxorguk ! ukuu ! org ! uk>
Date:       1999-11-20 15:04:58
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> /* 3 asm instructions */
> void release_exclusive(struct rw_mutex* rwm)
> {
>         read_unlock(&rwm->rwl);
>         if(rwm->wake_me_up) {
>                 rwm->wake_me_up = 0;
>                 wake_up(&rwm->wait);
>         }
> }

That can race with another acquire surely. Suppose they set rmw->wake_me_up
and we then continue our release and clear it. Actually why do you want the
wake_me_up field ?


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