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ip: Fix ip_dev_loopback_xmit()

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Eric Paris got following trace with a linux-next kernel

[   14.203970] BUG: using smp_processor_id() in preemptible [00000000]
code: avahi-daemon/2093
[   14.204025] caller is netif_rx+0xfa/0x110
[   14.204035] Call Trace:
[   14.204064]  [<ffffffff81278fe5>] debug_smp_processor_id+0x105/0x110
[   14.204070]  [<ffffffff8142163a>] netif_rx+0xfa/0x110
[   14.204090]  [<ffffffff8145b631>] ip_dev_loopback_xmit+0x71/0xa0
[   14.204095]  [<ffffffff8145b892>] ip_mc_output+0x192/0x2c0
[   14.204099]  [<ffffffff8145d610>] ip_local_out+0x20/0x30
[   14.204105]  [<ffffffff8145d8ad>] ip_push_pending_frames+0x28d/0x3d0
[   14.204119]  [<ffffffff8147f1cc>] udp_push_pending_frames+0x14c/0x400
[   14.204125]  [<ffffffff814803fc>] udp_sendmsg+0x39c/0x790
[   14.204137]  [<ffffffff814891d5>] inet_sendmsg+0x45/0x80
[   14.204149]  [<ffffffff8140af91>] sock_sendmsg+0xf1/0x110
[   14.204189]  [<ffffffff8140dc6c>] sys_sendmsg+0x20c/0x380
[   14.204233]  [<ffffffff8100ad82>] system_call_fastpath+0x16/0x1b

While current linux-2.6 kernel doesnt emit this warning, bug is latent
and might cause unexpected failures.

ip_dev_loopback_xmit() runs in process context, preemption enabled, so
must call netif_rx_ni() instead of netif_rx(), to make sure that we
process pending software interrupt.

Same change for ip6_dev_loopback_xmit()

Reported-by: Eric Paris <eparis@redhat.com>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric Dumazet 2010-04-15 09:13:03 +00:00 committed by David S. Miller
parent 8728c544a9
commit e30b38c298
2 changed files with 2 additions and 2 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

2
net/ipv4/ip_output.c
View file

@ -120,7 +120,7 @@ static int ip_dev_loopback_xmit(struct sk_buff *newskb)
newskb->pkt_type = PACKET_LOOPBACK; newskb->pkt_type = PACKET_LOOPBACK;
newskb->ip_summed = CHECKSUM_UNNECESSARY; newskb->ip_summed = CHECKSUM_UNNECESSARY;
WARN_ON(!skb_dst(newskb)); WARN_ON(!skb_dst(newskb));
netif_rx(newskb); netif_rx_ni(newskb);
return 0; return 0;
} }

2
net/ipv6/ip6_output.c
View file

@ -108,7 +108,7 @@ static int ip6_dev_loopback_xmit(struct sk_buff *newskb)
newskb->ip_summed = CHECKSUM_UNNECESSARY; newskb->ip_summed = CHECKSUM_UNNECESSARY;
WARN_ON(!skb_dst(newskb)); WARN_ON(!skb_dst(newskb));
netif_rx(newskb); netif_rx_ni(newskb);
return 0; return 0;
} }