From: David Miller <davem-fT/PcQaiUtIeIZ0/mPfg9Q@public.gmane.org>
To: fbl-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org
Cc: netdev-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
dev-yBygre7rU0SM8Zsap4Y0gw@public.gmane.org
Subject: Re: [PATCH net] openvswitch: fix a possible deadlock and lockdep warning
Date: Fri, 28 Mar 2014 16:36:39 -0400 (EDT) [thread overview]
Message-ID: <20140328.163639.788185926435545136.davem@davemloft.net> (raw)
In-Reply-To: <1395924836-3182-1-git-send-email-fbl-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
From: Flavio Leitner <fbl-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
Date: Thu, 27 Mar 2014 09:53:56 -0300
> There are two problematic situations.
>
> A deadlock can happen when is_percpu is false because it can get
> interrupted while holding the spinlock. Then it executes
> ovs_flow_stats_update() in softirq context which tries to get
> the same lock.
>
> The second sitation is that when is_percpu is true, the code
> correctly disables BH only for the local CPU, but that confuses
> lockdep enough to trigger the warning below.
>
> This patch disables BH for both cases fixing the real deadlock
> and the lockdep warning message.
...
> Signed-off-by: Flavio Leitner <fbl-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
I'll let Jesse review and pick this up.
next prev parent reply other threads:[~2014-03-28 20:36 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-03-27 12:53 [PATCH net] openvswitch: fix a possible deadlock and lockdep warning Flavio Leitner
[not found] ` <1395924836-3182-1-git-send-email-fbl-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2014-03-28 20:36 ` David Miller [this message]
-- strict thread matches above, loose matches on Subject: below --
2014-03-27 0:56 Flavio Leitner
2014-03-27 12:52 ` Flavio Leitner
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