From: Jonathan Corbet <corbet@lwn.net>
To: Markus Trippelsdorf <markus@trippelsdorf.de>
Cc: "Ilpo Järvinen" <ilpo.jarvinen@helsinki.fi>,
Netdev <netdev@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: WARNING: at net/ipv4/tcp_input.c:2927 tcp_ack+0xd55/0x1991()
Date: Sat, 28 Mar 2009 07:56:28 -0600 [thread overview]
Message-ID: <20090328075628.3565eb39@bike.lwn.net> (raw)
In-Reply-To: <20090328095514.GA2599@gentoox2.trippelsdorf.de>
On Sat, 28 Mar 2009 10:55:14 +0100
Markus Trippelsdorf <markus@trippelsdorf.de> wrote:
> Yes, you might be right, because running with CONFIG_PROVE_LOCKING and
> CONFIG_DETECT_SOFTLOCKUP enabled points to a possible bug in the BKL
> removal patches (fasync) by Jonathan Corbet. (I wasn't able so far to
> reproduce the original WARNING.)
>
> Here is one example:
>
> =========================================================
> [ INFO: possible irq lock inversion dependency detected ]
> 2.6.29-03321-gbe0ea69 #7
> ---------------------------------------------------------
> swapper/0 just changed the state of lock:
> (fasync_lock){..+.}, at: [<ffffffff8028a2ac>] kill_fasync+0x24/0x45
> but this lock took another, hard-irq-unsafe lock in the past:
> (&f->f_lock){--..}
That's not a bug; f_lock will never be taken in IRQ mode. There's a
fix for the warning in linux-next now; my plan is to get it upstream
before -rc1.
Thanks,
jon
Jonathan Corbet / LWN.net / corbet@lwn.net
next prev parent reply other threads:[~2009-03-28 13:56 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-03-27 21:12 Markus Trippelsdorf
2009-03-27 23:05 ` Ilpo Järvinen
2009-03-28 4:50 ` Markus Trippelsdorf
2009-03-28 8:29 ` Ilpo Järvinen
2009-03-28 9:55 ` Markus Trippelsdorf
2009-03-28 13:56 ` Jonathan Corbet [this message]
2009-03-30 8:51 ` Jarek Poplawski
2009-03-30 14:01 ` Jonathan Corbet
2009-03-30 16:40 ` Jarek Poplawski
2009-03-30 16:01 ` Ilpo Järvinen
2009-03-30 16:40 ` Markus Trippelsdorf
2009-03-30 18:52 ` Ilpo Järvinen
2009-03-31 7:10 ` Markus Trippelsdorf
2009-03-31 9:16 ` Ilpo Järvinen
2009-03-31 18:49 ` Markus Trippelsdorf
2009-03-31 19:12 ` Ilpo Järvinen
2009-04-01 7:00 ` Ilpo Järvinen
2009-04-01 11:09 ` Ilpo Järvinen
2009-04-01 11:35 ` Markus Trippelsdorf
2009-04-02 9:15 ` [PATCH 1/2] tcp: add helper for counter tweaking due mid-wq change Ilpo Järvinen
2009-04-02 9:18 ` [PATCH 2/2] tcp: miscounts due to tcp_fragment pcount reset Ilpo Järvinen
2009-04-02 23:32 ` David Miller
2009-04-02 23:32 ` [PATCH 1/2] tcp: add helper for counter tweaking due mid-wq change David Miller
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