From b2238566401f01eb796e75750213c7b0fce396b2 Mon Sep 17 00:00:00 2001 From: Andrey Vagin Date: Tue, 8 Jul 2008 15:13:31 -0700 Subject: [PATCH] ipv6: fix race between ipv6_del_addr and DAD timer Consider the following scenario: ipv6_del_addr(ifp) ipv6_ifa_notify(RTM_DELADDR, ifp) ip6_del_rt(ifp->rt) after returning from the ipv6_ifa_notify and enabling BH-s back, but *before* calling the addrconf_del_timer the ifp->timer fires and: addrconf_dad_timer(ifp) addrconf_dad_completed(ifp) ipv6_ifa_notify(RTM_NEWADDR, ifp) ip6_ins_rt(ifp->rt) then return back to the ipv6_del_addr and: in6_ifa_put(ifp) inet6_ifa_finish_destroy(ifp) dst_release(&ifp->rt->u.dst) After this we have an ifp->rt inserted into fib6 lists, but queued for gc, which in turn can result in oopses in the fib6_run_gc. Maybe some other nasty things, but we caught only the oops in gc so far. The solution is to disarm the ifp->timer before flushing the rt from it. Signed-off-by: Andrey Vagin Signed-off-by: Pavel Emelyanov Signed-off-by: David S. Miller --- net/ipv6/addrconf.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c index 147588f4c7c0..ff61a5cdb0b3 100644 --- a/net/ipv6/addrconf.c +++ b/net/ipv6/addrconf.c @@ -749,12 +749,12 @@ static void ipv6_del_addr(struct inet6_ifaddr *ifp) } write_unlock_bh(&idev->lock); + addrconf_del_timer(ifp); + ipv6_ifa_notify(RTM_DELADDR, ifp); atomic_notifier_call_chain(&inet6addr_chain, NETDEV_DOWN, ifp); - addrconf_del_timer(ifp); - /* * Purge or update corresponding prefix * -- 2.20.1