From fc0e8dacce6bf75898134727ef208980f159c471 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Wed, 18 May 2011 02:21:31 -0400 Subject: [PATCH] net: add skb_dst_force() in sock_queue_err_skb() BugLink: http://bugs.launchpad.net/bugs/793702 [ Upstream commit abb57ea48fd9431fa320a5c55f73e6b5a44c2efb ] Commit 7fee226ad239 (add a noref bit on skb dst) forgot to use skb_dst_force() on packets queued in sk_error_queue This triggers following warning, for applications using IP_CMSG_PKTINFO receiving one error status ------------[ cut here ]------------ WARNING: at include/linux/skbuff.h:457 ip_cmsg_recv_pktinfo+0xa6/0xb0() Hardware name: 2669UYD Modules linked in: isofs vboxnetadp vboxnetflt nfsd ebtable_nat ebtables lib80211_crypt_ccmp uinput xcbc hdaps tp_smapi thinkpad_ec radeonfb fb_ddc radeon ttm drm_kms_helper drm ipw2200 intel_agp intel_gtt libipw i2c_algo_bit i2c_i801 agpgart rng_core cfbfillrect cfbcopyarea cfbimgblt video raid10 raid1 raid0 linear md_mod vboxdrv Pid: 4697, comm: miredo Not tainted 2.6.39-rc6-00569-g5895198-dirty #22 Call Trace: [] ? printk+0x1d/0x1f [] warn_slowpath_common+0x72/0xa0 [] ? ip_cmsg_recv_pktinfo+0xa6/0xb0 [] ? ip_cmsg_recv_pktinfo+0xa6/0xb0 [] warn_slowpath_null+0x20/0x30 [] ip_cmsg_recv_pktinfo+0xa6/0xb0 [] ip_cmsg_recv+0x127/0x260 [] ? skb_dequeue+0x4d/0x70 [] ? skb_copy_datagram_iovec+0x53/0x300 [] ? sub_preempt_count+0x24/0x50 [] ip_recv_error+0x23d/0x270 [] udp_recvmsg+0x264/0x2b0 [] inet_recvmsg+0xd9/0x130 [] sock_recvmsg+0xf2/0x120 [] ? might_fault+0x4b/0xa0 [] ? verify_iovec+0x4c/0xc0 [] ? sock_recvmsg_nosec+0x100/0x100 [] __sys_recvmsg+0x114/0x1e0 [] ? __lock_acquire+0x365/0x780 [] ? fget_light+0xa6/0x3e0 [] ? fget_light+0xbf/0x3e0 [] ? fget_light+0x2e/0x3e0 [] sys_recvmsg+0x39/0x60 Close bug https://bugzilla.kernel.org/show_bug.cgi?id=34622 Reported-by: Witold Baryluk Signed-off-by: Eric Dumazet CC: Stephen Hemminger Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman Signed-off-by: Tim Gardner --- net/core/skbuff.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/net/core/skbuff.c b/net/core/skbuff.c index d883dcc..e9f92489 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -2997,6 +2997,9 @@ int sock_queue_err_skb(struct sock *sk, struct sk_buff *skb) skb->destructor = sock_rmem_free; atomic_add(skb->truesize, &sk->sk_rmem_alloc); + /* before exiting rcu section, make sure dst is refcounted */ + skb_dst_force(skb); + skb_queue_tail(&sk->sk_error_queue, skb); if (!sock_flag(sk, SOCK_DEAD)) sk->sk_data_ready(sk, skb->len); -- 1.7.10.4