From: Florian Westphal <fw@strlen.de>
To: Ani Sinha <ani@arista.com>
Cc: netdev@vger.kernel.org, ani@anirban.org, fruggeri@arista.com
Subject: Re: kernel BUG in ipmr_queue_xmit()
Date: Fri, 30 Oct 2015 01:15:10 +0100 [thread overview]
Message-ID: <20151030001510.GG18062@breakpoint.cc> (raw)
In-Reply-To: <alpine.OSX.2.00.1510291646320.59200@animac.local>
Ani Sinha <ani@arista.com> wrote:
[ trimmed CC list ]
> We are noticing the following kernel BUG in 3.18 kernel. The
> code path that leads to the crash is the following :
>
> ip_mroute_setsockopt()
> ->ipmr_mfc_add()
> ->ipmr_cache_resolve()
> ->ip_mr_forward()
> -> ipmr_queue_xmit()
> -> ipmr_forward_finish()
> ->IP_INC_STATS_BH()
> -> SNMP_INC_STATS64_BH()
> -> SNMP_INC_STATS_BH()
> -> __this_cpu_inc()
> -> __this_cpu_add()
> -> __this_cpu_preempt_check()
> -> check_preemption_disabled()
>
> I have verified that preempt_count() is 0 when the crash happens.
> Is anyone else seeing the same crash in the laetst upstream code? I dug
> around a little bit and it does not look like there were any fixes that
> went into post 3.18 kernel which could have disabled preemption in this
> code path but I could be wrong.
>
> thoughts?
Send a patch to preempt_disable before ip_mr_forward call in the affected
setsockopt path?
next prev parent reply other threads:[~2015-10-30 0:15 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-10-29 23:55 kernel BUG in ipmr_queue_xmit() Ani Sinha
2015-10-30 0:15 ` Florian Westphal [this message]
2015-10-30 1:41 ` Ani Sinha
2015-10-30 4:15 ` Eric Dumazet
2015-10-30 10:36 ` Florian Westphal
2015-10-30 10:40 ` Hannes Frederic Sowa
2015-10-30 10:48 ` Florian Westphal
2015-10-30 11:00 ` Eric Dumazet
2015-10-30 17:47 ` Ani Sinha
2015-10-30 19:12 ` Eric Dumazet
2015-10-30 21:10 ` Ani Sinha
2015-10-30 23:54 ` [PATCH 1/1] ipmr: fix possible race resulting from improper usage of IP_INC_STATS_BH() in preemptible context Ani Sinha
2015-11-01 22:35 ` Eric Dumazet
2015-11-02 20:57 ` David Miller
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