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authorNikolay Aleksandrov <nikolay@nvidia.com>2021-11-22 16:15:14 +0100
committerDavid S. Miller <davem@davemloft.net>2021-11-22 16:44:49 +0100
commit02ebe49ab06111a887202959e4d58a3cf252b5ee (patch)
tree7e63c1e285e3fc29cb0b3befcba9656d1b43ff30 /tools
parentnet: nexthop: release IPv6 per-cpu dsts when replacing a nexthop group (diff)
downloadlinux-02ebe49ab06111a887202959e4d58a3cf252b5ee.tar.xz
linux-02ebe49ab06111a887202959e4d58a3cf252b5ee.zip
selftests: net: fib_nexthops: add test for group refcount imbalance bug
The new selftest runs a sequence which causes circular refcount dependency between deleted objects which cannot be released and results in a netdevice refcount imbalance. Signed-off-by: Nikolay Aleksandrov <nikolay@nvidia.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'tools')
-rwxr-xr-xtools/testing/selftests/net/fib_nexthops.sh63
1 files changed, 63 insertions, 0 deletions
diff --git a/tools/testing/selftests/net/fib_nexthops.sh b/tools/testing/selftests/net/fib_nexthops.sh
index b5a69ad191b0..d444ee6aa3cb 100755
--- a/tools/testing/selftests/net/fib_nexthops.sh
+++ b/tools/testing/selftests/net/fib_nexthops.sh
@@ -629,6 +629,66 @@ ipv6_fcnal()
log_test $? 0 "Nexthops removed on admin down"
}
+ipv6_grp_refs()
+{
+ if [ ! -x "$(command -v mausezahn)" ]; then
+ echo "SKIP: Could not run test; need mausezahn tool"
+ return
+ fi
+
+ run_cmd "$IP link set dev veth1 up"
+ run_cmd "$IP link add veth1.10 link veth1 up type vlan id 10"
+ run_cmd "$IP link add veth1.20 link veth1 up type vlan id 20"
+ run_cmd "$IP -6 addr add 2001:db8:91::1/64 dev veth1.10"
+ run_cmd "$IP -6 addr add 2001:db8:92::1/64 dev veth1.20"
+ run_cmd "$IP -6 neigh add 2001:db8:91::2 lladdr 00:11:22:33:44:55 dev veth1.10"
+ run_cmd "$IP -6 neigh add 2001:db8:92::2 lladdr 00:11:22:33:44:55 dev veth1.20"
+ run_cmd "$IP nexthop add id 100 via 2001:db8:91::2 dev veth1.10"
+ run_cmd "$IP nexthop add id 101 via 2001:db8:92::2 dev veth1.20"
+ run_cmd "$IP nexthop add id 102 group 100"
+ run_cmd "$IP route add 2001:db8:101::1/128 nhid 102"
+
+ # create per-cpu dsts through nh 100
+ run_cmd "ip netns exec me mausezahn -6 veth1.10 -B 2001:db8:101::1 -A 2001:db8:91::1 -c 5 -t tcp "dp=1-1023, flags=syn" >/dev/null 2>&1"
+
+ # remove nh 100 from the group to delete the route potentially leaving
+ # a stale per-cpu dst which holds a reference to the nexthop's net
+ # device and to the IPv6 route
+ run_cmd "$IP nexthop replace id 102 group 101"
+ run_cmd "$IP route del 2001:db8:101::1/128"
+
+ # add both nexthops to the group so a reference is taken on them
+ run_cmd "$IP nexthop replace id 102 group 100/101"
+
+ # if the bug described in commit "net: nexthop: release IPv6 per-cpu
+ # dsts when replacing a nexthop group" exists at this point we have
+ # an unlinked IPv6 route (but not freed due to stale dst) with a
+ # reference over the group so we delete the group which will again
+ # only unlink it due to the route reference
+ run_cmd "$IP nexthop del id 102"
+
+ # delete the nexthop with stale dst, since we have an unlinked
+ # group with a ref to it and an unlinked IPv6 route with ref to the
+ # group, the nh will only be unlinked and not freed so the stale dst
+ # remains forever and we get a net device refcount imbalance
+ run_cmd "$IP nexthop del id 100"
+
+ # if a reference was lost this command will hang because the net device
+ # cannot be removed
+ timeout -s KILL 5 ip netns exec me ip link del veth1.10 >/dev/null 2>&1
+
+ # we can't cleanup if the command is hung trying to delete the netdev
+ if [ $? -eq 137 ]; then
+ return 1
+ fi
+
+ # cleanup
+ run_cmd "$IP link del veth1.20"
+ run_cmd "$IP nexthop flush"
+
+ return 0
+}
+
ipv6_grp_fcnal()
{
local rc
@@ -734,6 +794,9 @@ ipv6_grp_fcnal()
run_cmd "$IP nexthop add id 108 group 31/24"
log_test $? 2 "Nexthop group can not have a blackhole and another nexthop"
+
+ ipv6_grp_refs
+ log_test $? 0 "Nexthop group replace refcounts"
}
ipv6_res_grp_fcnal()