From: Alan Cox <alan@lxorguk.ukuu.org.uk>
To: Ingo Molnar <mingo@elte.hu>
Cc: linux-kernel@vger.kernel.org,
Pekka Enberg <penberg@cs.helsinki.fi>,
Vegard Nossum <vegard.nossum@gmail.com>,
"Rafael J. Wysocki" <rjw@sisk.pl>,
Andrew Morton <akpm@linux-foundation.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Peter Zijlstra <a.p.zijlstra@chello.nl>
Subject: Re: [bug] WARNING: at drivers/char/tty_io.c:1266 tty_open+0x1ea/0x388()
Date: Tue, 16 Jun 2009 11:13:16 +0100 [thread overview]
Message-ID: <20090616111316.6b3bb078@lxorguk.ukuu.org.uk> (raw)
In-Reply-To: <20090616071057.GA29862@elte.hu>
> I have applied your patch from yesterday (attached further below for
> reference) and the SLAB corruption has not triggered - instead i'm
> now getting this warning, after 96 reboots
That one is interesting btw - however its not a new bug. The WARN_ON()
was added in the new patches to catch cases where the tty open/close
locking was broken and see if all the ldisc related ones were nailed.
Apparently on a very SMP box they are not. It's not however a new bug -
just the result of checking for the problem.
+ WARN_ON(!test_bit(TTY_LDISC, &tty->flags));
..
which means that someone cleared the ldisc behind our back despite us
holding tty_mutex. That would suggest a hangup/reopen race which
shouldn't be too hard to find.
Dunno what you feed your SMP box but its very useful 8)
Alan
next prev parent reply other threads:[~2009-06-16 10:13 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-06-14 8:10 tty_ldisc_try_get(): BUG kmalloc-8: Poison overwritten Ingo Molnar
2009-06-14 8:20 ` Pekka Enberg
2009-06-14 8:30 ` Pekka Enberg
2009-06-14 8:32 ` Pekka Enberg
2009-06-14 23:03 ` Vegard Nossum
2009-06-15 4:25 ` Pekka Enberg
2009-06-14 8:32 ` Ingo Molnar
2009-06-14 8:35 ` Ingo Molnar
2009-06-14 12:32 ` Ingo Molnar
2009-06-14 10:54 ` Alan Cox
2009-06-15 9:10 ` Catalin Marinas
2009-06-16 7:10 ` [bug] WARNING: at drivers/char/tty_io.c:1266 tty_open+0x1ea/0x388() Ingo Molnar
2009-06-16 8:44 ` Alan Cox
2009-06-16 8:49 ` Ingo Molnar
2009-06-16 9:00 ` Alan Cox
2009-06-16 19:43 ` Ingo Molnar
2009-06-16 10:13 ` Alan Cox [this message]
2009-06-16 10:24 ` Ingo Molnar
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