From: Linus Torvalds <torvalds@osdl.org>
To: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>,
"Paul E. McKenney" <paulmck@us.ibm.com>,
linux-kernel@vger.kernel.org
Subject: Re: Badness in local_bh_enable by [PATCH] fix uidhash_lock <-> RCU deadlock
Date: Tue, 31 Jan 2006 15:20:17 -0800 (PST) [thread overview]
Message-ID: <Pine.LNX.4.64.0601311512230.7301@g5.osdl.org> (raw)
In-Reply-To: <20060131230926.GA7726@mipter.zuzino.mipt.ru>
On Wed, 1 Feb 2006, Alexey Dobriyan wrote:
>
> Flooding boot logs with
>
> Badness in local_bh_enable at kernel/softirq.c:140
Ok, looks bad. It's through
__dequeue_signal():
collect_signal():
__sigqueue_free():
free_uid()
where we hold the sigqueue lock. We do _not_ want to do BH processing
there with the lock held and interrupts disabled, so the warning is
correct, and that uidhash_lock patch potentially causes more problems than
it fixes.
Perhaps the easiest solution is to just make them irq-safe instead
of bh-safe? An alternative might be to make __sigqueue_free() do its work
through RCU callbacks too, but that seems wrong.
Comments? Ingo?
Linus
next prev parent reply other threads:[~2006-01-31 23:20 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-01-31 23:09 Badness in local_bh_enable by [PATCH] fix uidhash_lock <-> RCU deadlock Alexey Dobriyan
2006-01-31 23:20 ` Linus Torvalds [this message]
2006-02-01 1:59 ` Kumar Gala
2006-02-01 2:41 ` Peter Williams
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