From: "David S. Miller" <davem@davemloft.net>
To: Olaf Kirch <okir@suse.de>
Cc: netdev@oss.sgi.com
Subject: Re: [PATCH] Deadlock in af_packet/packet_rcv
Date: Mon, 29 Nov 2004 20:02:20 -0800 [thread overview]
Message-ID: <20041129200220.25ff3f7a.davem@davemloft.net> (raw)
In-Reply-To: <20041125205503.GA18083@suse.de>
On Thu, 25 Nov 2004 21:55:03 +0100
Olaf Kirch <okir@suse.de> wrote:
> Before introduction of lock-less loopback, all of netdev_xmit_nit was
> running with bottom halves disabled, and some code seems to rely on
> this. One of them is af_packet's packet_rcv handler, which is called
> from the receive path via netdev_xmit_nit. It takes a spin lock,
> and if an interrupt occurs and calls netdev_xmit during this time,
> the CPU deadlocks.
>
> The patch below disables BHs while in the TX path for loopback and
> similar devices.
>
> An alternative, less conservative fix would be to just use spin_lock_bh
> in af_packet.c.
Good spotting.
If it's only the dev_queue_xmit_nit() handlers which all want
BHs disabled, why don't we just disable BHs in that function?
next prev parent reply other threads:[~2004-11-30 4:02 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-11-25 20:55 [PATCH] Deadlock in af_packet/packet_rcv Olaf Kirch
2004-11-30 4:02 ` David S. Miller [this message]
2004-11-30 10:48 ` Olaf Kirch
2004-11-30 9:32 ` Tommy Christensen
2004-11-30 11:01 ` Olaf Kirch
2004-11-30 11:31 ` Tommy Christensen
2004-11-30 11:45 ` Olaf Kirch
2004-11-30 11:56 ` Tommy Christensen
2004-11-30 21:07 ` David S. Miller
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