# \[PATCH net\] packet: unconditionally free po-\>rollover - From: Willem de Bruijn \ - Date: 2019-05-31 16:37:29 - List: netdev - Page: https://ratatoskr.run/netdev/2019/05/11136647 - Thread: https://ratatoskr.run/netdev/2019/05/11136647/t.md ```text From: Willem de Bruijn Rollover used to use a complex RCU mechanism for assignment, which had a race condition. The below patch fixed the bug and greatly simplified the logic. The feature depends on fanout, but the state is private to the socket. Fanout_release returns f only when the last member leaves and the fanout struct is to be freed. Destroy rollover unconditionally, regardless of fanout state. Fixes: 57f015f5eccf2 ("packet: fix crash in fanout_demux_rollover()") Reported-by: syzbot Diagnosed-by: Dmitry Vyukov [ref] Signed-off-by: Willem de Bruijn --- net/packet/af_packet.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c index fbc775fbf7128..d4889bf7248e1 100644 --- a/net/packet/af_packet.c +++ b/net/packet/af_packet.c @@ -3014,8 +3014,8 @@ static int packet_release(struct socket *sock) synchronize_net(); + kfree(po->rollover); if (f) { - kfree(po->rollover); fanout_release_data(f); kfree(f); } -- 2.22.0.rc1.257.g3120a18244-goog ```