From: Michal Kubecek <mkubecek@suse.cz>
To: Sasha Levin <sashal@kernel.org>
Cc: Naresh Kamboju <naresh.kamboju@linaro.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
open list <linux-kernel@vger.kernel.org>,
linux- stable <stable@vger.kernel.org>,
Eric Dumazet <edumazet@google.com>,
Firo Yang <firo.yang@suse.com>,
Jakub Kicinski <jakub.kicinski@netronome.com>,
rcu@vger.kernel.org, Netdev <netdev@vger.kernel.org>,
lkft-triage@lists.linaro.org
Subject: Re: [PATCH AUTOSEL 4.19 46/84] tcp/dccp: fix possible race __inet_lookup_established()
Date: Thu, 9 Jan 2020 18:07:46 +0100 [thread overview]
Message-ID: <20200109170746.GO22387@unicorn.suse.cz> (raw)
In-Reply-To: <20200109153226.GG1706@sasha-vm>
On Thu, Jan 09, 2020 at 10:32:26AM -0500, Sasha Levin wrote:
> On Thu, Jan 02, 2020 at 01:31:22PM +0530, Naresh Kamboju wrote:
> > On Fri, 27 Dec 2019 at 23:17, Sasha Levin <sashal@kernel.org> wrote:
> > >
> > > From: Eric Dumazet <edumazet@google.com>
> > >
> > > [ Upstream commit 8dbd76e79a16b45b2ccb01d2f2e08dbf64e71e40 ]
> > >
> > > Michal Kubecek and Firo Yang did a very nice analysis of crashes
> > > happening in __inet_lookup_established().
> > >
> > > Since a TCP socket can go from TCP_ESTABLISH to TCP_LISTEN
> > > (via a close()/socket()/listen() cycle) without a RCU grace period,
> > > I should not have changed listeners linkage in their hash table.
> > >
> > > They must use the nulls protocol (Documentation/RCU/rculist_nulls.txt),
> > > so that a lookup can detect a socket in a hash list was moved in
> > > another one.
> > >
> > > Since we added code in commit d296ba60d8e2 ("soreuseport: Resolve
> > > merge conflict for v4/v6 ordering fix"), we have to add
> > > hlist_nulls_add_tail_rcu() helper.
> >
> > The kernel panic reported on all devices,
> > While running LTP syscalls accept* test cases on stable-rc-4.19 branch kernel.
> > This report log extracted from qemu_x86_64.
> >
> > Reverting this patch re-solved kernel crash.
>
> I'll drop it until we can look into what's happening here, thanks!
It was already discussed here:
http://lkml.kernel.org/r/CA+G9fYv3=oJSFodFp4wwF7G7_g5FWYRYbc4F0AMU6jyfLT689A@mail.gmail.com
and fixed version should be in 4.19, 4.14 and 4.9 stable branches now.
Michal Kubecek
prev parent reply other threads:[~2020-01-09 17:07 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20191227174352.6264-1-sashal@kernel.org>
2019-12-27 17:43 ` [PATCH AUTOSEL 4.19 46/84] tcp/dccp: fix possible race __inet_lookup_established() Sasha Levin
2020-01-02 8:01 ` Naresh Kamboju
2020-01-09 15:32 ` Sasha Levin
2020-01-09 17:07 ` Michal Kubecek [this message]
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