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Roman Kapl authored
If you flush (delete) a filter chain other than chain 0 (such as when deleting the device), the kernel may run into a use-after-free. The chain refcount must not be decremented unless we are sure we are done with the chain. To reproduce the bug, run: ip link add dtest type dummy tc qdisc add dev dtest ingress tc filter add dev dtest chain 1 parent ffff: flower ip link del dtest Introduced in: commit f93e1cdc ("net/sched: fix filter flushing"), but unless you have KAsan or luck, you won't notice it until commit 0dadc117 ("cls_flower: use tcf_exts_get_net() before call_rcu()") Fixes: f93e1cdc ("net/sched: fix filter flushing") Acked-by:
Jiri Pirko <jiri@mellanox.com> Signed-off-by:
Roman Kapl <code@rkapl.cz> Signed-off-by:
David S. Miller <davem@davemloft.net>
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