Commit d69efb16 authored Apr 29, 2008 by Bodo Stroesser Committed by David S. Miller Apr 29, 2008

bridge: kernel panic when unloading bridge module



There is a race condition when unloading bridge and netfilter.

The problem happens if __fake_rtable is in use by a skb
coming in, while someone starts to unload bridge.ko.
br_netfilter_fini() is called at the beginning of unload
in br_deinit() while skbs still are being forwarded and
transferred to local ip stack. Thus there is a possibility
of the __fake_rtable pointer not being removed in a skb that
goes up to ip stack. This results in a kernel panic, as
ip_rcv() calls the input-function of __fake_rtable, which
is NULL.

Moving the call of br_netfilter_fini() to the end of
br_deinit() solves the problem.

Signed-off-by: Bodo Stroesser <bstroesser@fujitsu-siemens.com>
Signed-off-by: Stephen Hemminger <stephen.hemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent 43af8532

net/bridge/br.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -76,7 +76,6 @@ static void __exit br_deinit(void)
		rcu_assign_pointer(br_stp_sap->rcv_func, NULL);

		br_netlink_fini();
		br_netfilter_fini();
		unregister_netdevice_notifier(&br_device_notifier);
		brioctl_set(NULL);

		@@ -84,6 +83,7 @@ static void __exit br_deinit(void)

		synchronize_net();

		br_netfilter_fini();
		llc_sap_put(br_stp_sap);
		br_fdb_get_hook = NULL;
		br_fdb_put_hook = NULL;

Admin message