Messages in this thread | | | Date | Thu, 9 Jan 2020 10:32:26 -0500 | From | Sasha Levin <> | Subject | Re: [PATCH AUTOSEL 4.19 46/84] tcp/dccp: fix possible race __inet_lookup_established() |
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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!
-- Thanks, Sasha
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