From: David Miller <davem@davemloft.net>
To: nikolay@cumulusnetworks.com
Cc: netdev@vger.kernel.org, yoshfuji@linux-ipv6.org,
syzkaller-bugs@googlegroups.com,
bot+eceb3204562c41a438fa1f2335e0fe4f6886d669@syzkaller.appspotmail.com,
kuznet@ms2.inr.ac.ru, roopa@cumulusnetworks.com,
ebiggers3@gmail.com
Subject: Re: [PATCH net v2] ip6mr: fix stale iterator
Date: Wed, 31 Jan 2018 10:34:00 -0500 (EST) [thread overview]
Message-ID: <20180131.103400.2134338827807349026.davem@davemloft.net> (raw)
In-Reply-To: <1517408970-14210-1-git-send-email-nikolay@cumulusnetworks.com>
From: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Date: Wed, 31 Jan 2018 16:29:30 +0200
> When we dump the ip6mr mfc entries via proc, we initialize an iterator
> with the table to dump but we don't clear the cache pointer which might
> be initialized from a prior read on the same descriptor that ended. This
> can result in lock imbalance (an unnecessary unlock) leading to other
> crashes and hangs. Clear the cache pointer like ipmr does to fix the issue.
> Thanks for the reliable reproducer.
>
> Here's syzbot's trace:
...
> Reported-by: syzbot <bot+eceb3204562c41a438fa1f2335e0fe4f6886d669@syzkaller.appspotmail.com>
> Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
> ---
> v2: make sure the trace doesn't ruin the patch
> No fixes tag because it seems this has been there forever.
Applied and queued up for -stable.
prev parent reply other threads:[~2018-01-31 15:34 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-12-16 7:52 WARNING: bad unlock balance in ipmr_mfc_seq_stop syzbot
2018-01-31 0:30 ` Eric Biggers
2018-01-31 13:39 ` [PATCH net] ip6mr: fix stale iterator cache pointer Nikolay Aleksandrov
2018-01-31 14:29 ` [PATCH net v2] ip6mr: fix stale iterator Nikolay Aleksandrov
2018-01-31 14:49 ` Dmitry Vyukov
2018-01-31 14:52 ` Nikolay Aleksandrov
2018-01-31 15:11 ` Dmitry Vyukov
2018-01-31 15:21 ` David Miller
2018-01-31 15:34 ` David Miller [this message]
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