From: Al Viro <viro@ZenIV.linux.org.uk>
To: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Jens Axboe <axboe@kernel.dk>,
Andrew Morton <akpm@linux-foundation.org>,
Kay Sievers <kay.sievers@vrfy.org>,
Namhyung Kim <namhyung@gmail.com>,
Lukas Czerner <lczerner@redhat.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] loop: fput() called in loop_clr_fd() may cause bd_mutex recursive locking
Date: Sat, 17 Dec 2011 22:58:46 +0000 [thread overview]
Message-ID: <20111217225846.GC2203@ZenIV.linux.org.uk> (raw)
In-Reply-To: <20111217223745.GC3313@swordfish>
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? IOW, we have to
prevent such setups anyway and not just because of problems on close() -
they would be deadly on read() and write()...
next prev parent reply other threads:[~2011-12-17 22:58 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-12-17 21:53 Sergey Senozhatsky
2011-12-17 22:12 ` Al Viro
2011-12-17 22:19 ` Sergey Senozhatsky
2011-12-17 22:30 ` Al Viro
2011-12-17 22:37 ` Sergey Senozhatsky
2011-12-17 22:58 ` Al Viro [this message]
2011-12-17 23:20 ` Sergey Senozhatsky
2011-12-17 23:38 ` Al Viro
2011-12-17 23:47 ` Sergey Senozhatsky
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