From: Ingo Molnar <mingo@elte.hu>
To: Andrew Morton <akpm@osdl.org>
Cc: rostedt@goodmis.org, linux-kernel@vger.kernel.org, viro@ftp.linux.org.uk
Subject: Re: [patch, validator] fix proc_subdir_lock related deadlock
Date: Wed, 25 Jan 2006 21:21:42 +0100 [thread overview]
Message-ID: <20060125202142.GA12823@elte.hu> (raw)
In-Reply-To: <20060125102351.28cd52b8.akpm@osdl.org>
* Andrew Morton <akpm@osdl.org> wrote:
> > to solve this we must either change files_lock to be softirq-safe too
> > (bleh!), or we must forbid remove_proc_entry() use from softirq
> > contexts. Neither is a happy solution - remove_proc_entry() is used
> > within free_irq(), and who knows how many drivers do free_irq() in
> > softirq/tasklet context ...
>
> free_irq()'s /proc fiddling has always been a pain - we just shouldn't
> be doing filesystem things in irq/bh context.
the second patch i sent is quite straightforward.
> > Andrew, this needs to be resolved before v2.6.16, correct? Steve's patch
> > solves a real bug in the upstream kernel.
>
> It's not a very big bug - I think only Steve hit it, and that with a
> stress-test which was somewhat tuned to hit it.
still ...
> So we can afford to sit on the problem for a while, as long as someone
> is working on a broader /proc-sanity fix. But nobody will do that.
>
> I wonder if we can just punt the unregister_handler_proc/kfree up to a
> keventd callback.
i'd rather do the files_lock change i sent, and perhaps add a
WARN_ON_ONCE() to all known places that do a free_irq() from softirq
context.
Ingo
next prev parent reply other threads:[~2006-01-25 20:21 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-01-25 17:03 [patch, validator] fix proc_subdir_lock related deadlock Ingo Molnar
2006-01-25 17:14 ` Steven Rostedt
2006-01-25 18:08 ` Ingo Molnar
2006-01-25 18:14 ` [patch, validator] fix files_lock " Ingo Molnar
2006-01-25 18:23 ` [patch, validator] fix proc_subdir_lock " Andrew Morton
2006-01-25 20:21 ` Ingo Molnar [this message]
2006-01-26 0:02 ` [patch, lock validator] fix proc_inum_lock " Ingo Molnar
2006-01-26 0:11 ` Ingo Molnar
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