syzkaller found a way to trigger double frees from ip_mc_drop_socket()
It turns out that leave a copy of parent mc_list at accept() time,
which is very bad.
Very similar to commit 8b485ce69876 ("tcp: do not inherit
fastopen_req from parent")
Initial report from Pray3r, completed by Andrey one.
Thanks a lot to them !
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Pray3r <pray3r.z@gmail.com>
Reported-by: Andrey Konovalov <andreyknvl@google.com>
Tested-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
657831ffc3