4.4-stable review patch. If anyone has any objections, please let me know.
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From: Lorenzo Bianconi lorenzo.bianconi@redhat.com
[ Upstream commit 9fc12023d6f51551d6ca9ed7e02ecc19d79caf17 ]
Remove BUG_ON() from fib_compute_spec_dst routine and check in_dev pointer during flowi4 data structure initialization. fib_compute_spec_dst routine can be run concurrently with device removal where ip_ptr net_device pointer is set to NULL. This can happen if userspace enables pkt info on UDP rx socket and the device is removed while traffic is flowing
Fixes: 35ebf65e851c ("ipv4: Create and use fib_compute_spec_dst() helper") Signed-off-by: Lorenzo Bianconi lorenzo.bianconi@redhat.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/ipv4/fib_frontend.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
--- a/net/ipv4/fib_frontend.c +++ b/net/ipv4/fib_frontend.c @@ -289,19 +289,19 @@ __be32 fib_compute_spec_dst(struct sk_bu return ip_hdr(skb)->daddr;
in_dev = __in_dev_get_rcu(dev); - BUG_ON(!in_dev);
net = dev_net(dev);
scope = RT_SCOPE_UNIVERSE; if (!ipv4_is_zeronet(ip_hdr(skb)->saddr)) { + bool vmark = in_dev && IN_DEV_SRC_VMARK(in_dev); struct flowi4 fl4 = { .flowi4_iif = LOOPBACK_IFINDEX, .flowi4_oif = l3mdev_master_ifindex_rcu(dev), .daddr = ip_hdr(skb)->saddr, .flowi4_tos = RT_TOS(ip_hdr(skb)->tos), .flowi4_scope = scope, - .flowi4_mark = IN_DEV_SRC_VMARK(in_dev) ? skb->mark : 0, + .flowi4_mark = vmark ? skb->mark : 0, }; if (!fib_lookup(net, &fl4, &res, 0)) return FIB_RES_PREFSRC(net, res);