Sorry, looks like there's a backport already in stable-queue. Pleas ignore this.
On Mon, Mar 27, 2023 at 3:04 PM Nobel Barakat nobelbarakat@google.com wrote:
From: Davide Caratti dcaratti@redhat.com
commit ca22da2fbd693b54dc8e3b7b54ccc9f7e9ba3640 upstream
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/33dc43f587ec1388ba456b4915c75f02a8aae226.1663... [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: Nobel Barakat nobelbarakat@google.com
net/sched/act_mirred.c | 7 ++ .../selftests/net/forwarding/tc_actions.sh | 92 ++++++++++++++++++- 2 files changed, 98 insertions(+), 1 deletion(-)
diff --git a/net/sched/act_mirred.c b/net/sched/act_mirred.c index d64b0eeccbe4..120fd3ef8827 100644 --- a/net/sched/act_mirred.c +++ b/net/sched/act_mirred.c @@ -203,12 +203,19 @@ static int tcf_mirred_init(struct net *net, struct nlattr *nla, return err; }
+static bool is_mirred_nested(void) +{
return unlikely(__this_cpu_read(mirred_nest_level) > 1);+}
static int tcf_mirred_forward(bool want_ingress, struct sk_buff *skb) { int err;
if (!want_ingress) err = tcf_dev_queue_xmit(skb, dev_queue_xmit);
else if (is_mirred_nested())err = netif_rx(skb); else err = netif_receive_skb(skb);diff --git a/tools/testing/selftests/net/forwarding/tc_actions.sh b/tools/testing/selftests/net/forwarding/tc_actions.sh index d9eca227136b..f9070b3bdba2 100755 --- a/tools/testing/selftests/net/forwarding/tc_actions.sh +++ b/tools/testing/selftests/net/forwarding/tc_actions.sh @@ -3,7 +3,8 @@
ALL_TESTS="gact_drop_and_ok_test mirred_egress_redirect_test \ mirred_egress_mirror_test matchall_mirred_egress_mirror_test \
gact_trap_test"
gact_trap_test mirred_egress_to_ingress_test \mirred_egress_to_ingress_tcp_test"NUM_NETIFS=4 source tc_common.sh source lib.sh @@ -153,6 +154,95 @@ gact_trap_test() log_test "trap ($tcflags)" }
+mirred_egress_to_ingress_test() +{
RET=0tc filter add dev $h1 protocol ip pref 100 handle 100 egress flower \ip_proto icmp src_ip 192.0.2.1 dst_ip 192.0.2.2 type 8 action \ct commit nat src addr 192.0.2.2 pipe \ct clear pipe \ct commit nat dst addr 192.0.2.1 pipe \mirred ingress redirect dev $h1tc filter add dev $swp1 protocol ip pref 11 handle 111 ingress flower \ip_proto icmp src_ip 192.0.2.1 dst_ip 192.0.2.2 type 8 action droptc filter add dev $swp1 protocol ip pref 12 handle 112 ingress flower \ip_proto icmp src_ip 192.0.2.1 dst_ip 192.0.2.2 type 0 action pass$MZ $h1 -c 1 -p 64 -a $h1mac -b $h2mac -A 192.0.2.1 -B 192.0.2.2 \-t icmp "ping,id=42,seq=10" -qtc_check_packets "dev $h1 egress" 100 1check_err $? "didn't mirror first packet"tc_check_packets "dev $swp1 ingress" 111 1check_fail $? "didn't redirect first packet"tc_check_packets "dev $swp1 ingress" 112 1check_err $? "didn't receive reply to first packet"ping 192.0.2.2 -I$h1 -c1 -w1 -q 1>/dev/null 2>&1tc_check_packets "dev $h1 egress" 100 2check_err $? "didn't mirror second packet"tc_check_packets "dev $swp1 ingress" 111 1check_fail $? "didn't redirect second packet"tc_check_packets "dev $swp1 ingress" 112 2check_err $? "didn't receive reply to second packet"tc filter del dev $h1 egress protocol ip pref 100 handle 100 flowertc filter del dev $swp1 ingress protocol ip pref 11 handle 111 flowertc filter del dev $swp1 ingress protocol ip pref 12 handle 112 flowerlog_test "mirred_egress_to_ingress ($tcflags)"+}
+mirred_egress_to_ingress_tcp_test() +{
local tmpfile=$(mktemp) tmpfile1=$(mktemp)RET=0dd conv=sparse status=none if=/dev/zero bs=1M count=2 of=$tmpfiletc filter add dev $h1 protocol ip pref 100 handle 100 egress flower \$tcflags ip_proto tcp src_ip 192.0.2.1 dst_ip 192.0.2.2 \action ct commit nat src addr 192.0.2.2 pipe \action ct clear pipe \action ct commit nat dst addr 192.0.2.1 pipe \action ct clear pipe \action skbedit ptype host pipe \action mirred ingress redirect dev $h1tc filter add dev $h1 protocol ip pref 101 handle 101 egress flower \$tcflags ip_proto icmp \action mirred ingress redirect dev $h1tc filter add dev $h1 protocol ip pref 102 handle 102 ingress flower \ip_proto icmp \action dropip vrf exec v$h1 nc --recv-only -w10 -l -p 12345 -o $tmpfile1 &local rpid=$!ip vrf exec v$h1 nc -w1 --send-only 192.0.2.2 12345 <$tmpfilewait -n $rpidcmp -s $tmpfile $tmpfile1check_err $? "server output check failed"$MZ $h1 -c 10 -p 64 -a $h1mac -b $h1mac -A 192.0.2.1 -B 192.0.2.1 \-t icmp "ping,id=42,seq=5" -qtc_check_packets "dev $h1 egress" 101 10check_err $? "didn't mirred redirect ICMP"tc_check_packets "dev $h1 ingress" 102 10check_err $? "didn't drop mirred ICMP"local overlimits=$(tc_rule_stats_get ${h1} 101 egress .overlimits)test ${overlimits} = 10check_err $? "wrong overlimits, expected 10 got ${overlimits}"tc filter del dev $h1 egress protocol ip pref 100 handle 100 flowertc filter del dev $h1 egress protocol ip pref 101 handle 101 flowertc filter del dev $h1 ingress protocol ip pref 102 handle 102 flowerrm -f $tmpfile $tmpfile1log_test "mirred_egress_to_ingress_tcp ($tcflags)"+}
setup_prepare() { h1=${NETIFS[p1]} -- 2.40.0.348.gf938b09366-goog