From: Dmitry Vyukov <dvyukov@google.com>
To: Paolo Abeni <pabeni@redhat.com>
Cc: syzbot <syzbot+d1b1723faccb7a43f6d1@syzkaller.appspotmail.com>,
David Miller <davem@davemloft.net>,
Jakub Kicinski <kuba@kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
mathew.j.martineau@linux.intel.com, matthieu.baerts@tessares.net,
mptcp@lists.01.org, netdev <netdev@vger.kernel.org>,
syzkaller-bugs <syzkaller-bugs@googlegroups.com>
Subject: Re: possible deadlock in mptcp_push_pending
Date: Thu, 18 Feb 2021 15:04:02 +0100 [thread overview]
Message-ID: <CACT4Y+b3nZ=SXbRo7FUV5BO4r1kyPyPSUXG9=TNWBtOzLRFa_g@mail.gmail.com> (raw)
In-Reply-To: <639082dd7bddce31122200cc0e587c482379d1a7.camel@redhat.com>
On Thu, Feb 18, 2021 at 1:41 PM Paolo Abeni <pabeni@redhat.com> wrote:
>
> On Wed, 2021-02-17 at 09:31 -0800, syzbot wrote:
> > syzbot found the following issue on:
> >
> > HEAD commit: c48f8607 Merge branch 'PTP-for-DSA-tag_ocelot_8021q'
> > git tree: net-next
> > console output: https://syzkaller.appspot.com/x/log.txt?x=16525cb0d00000
> > kernel config: https://syzkaller.appspot.com/x/.config?x=dbc1ca9e55dc1f9f
> > dashboard link: https://syzkaller.appspot.com/bug?extid=d1b1723faccb7a43f6d1
> >
> > Unfortunately, I don't have any reproducer for this issue yet.
> >
> > IMPORTANT: if you fix the issue, please add the following tag to the commit:
> > Reported-by: syzbot+d1b1723faccb7a43f6d1@syzkaller.appspotmail.com
> >
> > ============================================
> > WARNING: possible recursive locking detected
> > 5.11.0-rc7-syzkaller #0 Not tainted
> > --------------------------------------------
> > syz-executor.1/15600 is trying to acquire lock:
> > ffff888057303220 (sk_lock-AF_INET6){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1598 [inline]
> > ffff888057303220 (sk_lock-AF_INET6){+.+.}-{0:0}, at: mptcp_push_pending+0x28b/0x650 net/mptcp/protocol.c:1466
>
> Even this one is suspected to be a dup of 'WARNING in dst_release': the
> subflow socket lock family is reported to be 'sk_lock-AF_INET6', but
> subflows are created in kernel, and get 'k-sk_lock-AF_INET6'. This
> looks like [re]use after free, likely via msk->first, as in the
> suspected dup issue. Lacking a repro, I'm not 110% sure.
>
> @Dmitry, I'm wondering which is the preferred course of action here:
> tentatively marking this one as a dup, or leaving it alone till we get
> a reproducer?
Hi Paolo,
I don't have a strong opinion. Either way will work, especially since
this seems to happen regularly. Or, submit a fix and wait to see if
this stops happening or not.
prev parent reply other threads:[~2021-02-18 16:55 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-17 17:31 possible deadlock in mptcp_push_pending syzbot
2021-02-18 12:41 ` Paolo Abeni
2021-02-18 14:04 ` Dmitry Vyukov [this message]
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