The following test case causes a NULL pointer dereference in cls_flow:
tc filter add dev foo parent 1: handle 0x1 flow hash keys dst action ok
tc filter replace dev foo parent 1: pref 49152 handle 0x1 \
flow hash keys mark action drop
To be more precise, actually two different panics are fixed, the first
occurs because tcf_exts_init() is not called on the newly allocated
filter when we do a replace. And the second panic uncovered after that
happens since the arguments of list_replace_rcu() are swapped, the old
element needs to be the first argument and the new element the second.
Fixes: 70da9f0bf9 ("net: sched: cls_flow use RCU")
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: John Fastabend <john.r.fastabend@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
32b2f4b196