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Davide Caratti 169a410739 act_mirred: use the backlog for nested calls to mirred ingress ... [ Upstream commit ca22da2fbd ] William reports kernel soft-lockups on some OVS topologies when TC mirred egress->ingress action is hit by local TCP traffic [1]. The same can also be reproduced with SCTP (thanks Xin for verifying), when client and server reach themselves through mirred egress to ingress, and one of the two peers sends a "heartbeat" packet (from within a timer). Enqueueing to backlog proved to fix this soft lockup; however, as Cong noticed [2], we should preserve - when possible - the current mirred behavior that counts as "overlimits" any eventual packet drop subsequent to the mirred forwarding action [3]. A compromise solution might use the backlog only when tcf_mirred_act() has a nest level greater than one: change tcf_mirred_forward() accordingly. Also, add a kselftest that can reproduce the lockup and verifies TC mirred ability to account for further packet drops after TC mirred egress->ingress (when the nest level is 1). [1] https://lore.kernel.org/netdev/33dc43f587ec1388ba456b4915c75f02a8aae226.1663945716.git.dcaratti@redhat.com/ [2] https://lore.kernel.org/netdev/Y0w%2FWWY60gqrtGLp@pop-os.localdomain/ [3] such behavior is not guaranteed: for example, if RPS or skb RX timestamping is enabled on the mirred target device, the kernel can defer receiving the skb and return NET_RX_SUCCESS inside tcf_mirred_forward(). Reported-by: William Zhao <wizhao@redhat.com> CC: Xin Long <lucien.xin@gmail.com> Signed-off-by: Davide Caratti <dcaratti@redhat.com> Reviewed-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> Acked-by: Jamal Hadi Salim <jhs@mojatatu.com> Signed-off-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Sasha Levin <sashal@kernel.org>		History 2023-03-30 12:47:55 +02:00
..
fault-injection	docs: fault-injection: convert docs to ReST and rename to *.rst	2019-06-14 14:21:07 -06:00
ktest	ktest.pl: Add RUN_TIMEOUT option with default unlimited	2023-03-10 09:40:10 +01:00
kunit	kunit: tool: Import missing importlib.abc	2022-02-23 12:03:04 +01:00
nvdimm	memremap: remove support for external pgmap refcounts	2022-08-17 14:23:43 +02:00
radix-tree	idr test suite: Improve reporting from idr_find_test_1	2021-04-01 07:50:42 -04:00
scatterlist	Merge branch 'akpm' (patches from Andrew)	2021-09-03 10:08:28 -07:00
selftests	act_mirred: use the backlog for nested calls to mirred ingress	2023-03-30 12:47:55 +02:00
vsock	vsock_diag_test: remove free_sock_stat() call in test_no_sockets	2021-10-15 17:21:34 -07:00