From 1215e51edad1272e669172b26aa12aac94810c7f Mon Sep 17 00:00:00 2001 From: WANG Cong Date: Wed, 12 Apr 2017 12:32:13 -0700 Subject: ipv4: fix a deadlock in ip_ra_control Similar to commit 87e9f0315952 ("ipv4: fix a potential deadlock in mcast getsockopt() path"), there is a deadlock scenario for IP_ROUTER_ALERT too: CPU0 CPU1 ---- ---- lock(rtnl_mutex); lock(sk_lock-AF_INET); lock(rtnl_mutex); lock(sk_lock-AF_INET); Fix this by always locking RTNL first on all setsockopt() paths. Note, after this patch ip_ra_lock is no longer needed either. Reported-by: Dmitry Vyukov Tested-by: Andrey Konovalov Signed-off-by: Cong Wang Signed-off-by: David S. Miller --- net/ipv4/ip_sockglue.c | 1 + 1 file changed, 1 insertion(+) (limited to 'net/ipv4/ip_sockglue.c') diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c index ebd953bc5607..bda318ae9876 100644 --- a/net/ipv4/ip_sockglue.c +++ b/net/ipv4/ip_sockglue.c @@ -591,6 +591,7 @@ static bool setsockopt_needs_rtnl(int optname) case MCAST_LEAVE_GROUP: case MCAST_LEAVE_SOURCE_GROUP: case MCAST_UNBLOCK_SOURCE: + case IP_ROUTER_ALERT: return true; } return false; -- cgit v1.2.3-59-g8ed1b