Messages in this thread | | | Date | Sun, 18 Dec 2011 02:20:53 +0300 | From | Sergey Senozhatsky <> | Subject | Re: [PATCH] loop: fput() called in loop_clr_fd() may cause bd_mutex recursive locking |
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On (12/17/11 22:58), Al Viro wrote: > On Sun, Dec 18, 2011 at 01:37:45AM +0300, Sergey Senozhatsky wrote: > > > Think of it for a minute - if we could run into the > > > same bdev in that recursion, what would have happened on read() from > > > that sucker? So yes, it is a false positive. > > > > I've tried read()/write() some time ago and it worked. Perhaps, I just > > wasn't "lucky" enough to hit any problems. > > Sure - exactly because of that loop prevention logics. *If* we really > had been able to set a loop0 -> loop1 -> loop2 -> loop0 or something of > that sort, this warning wouldn't be a false positive. But on any > such setup, where would IO attempts end up doing?
Thanks for your explanations.
> IOW, we have to prevent such setups anyway and not just because of > problems on close() - they would be deadly on read() and write()... >
Preventing recursion in the first place? For example, in lo_open()?
Sergey
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