From mboxrd@z Thu Jan  1 00:00:00 1970
From: Russell King - ARM Linux <linux@arm.linux.org.uk>
Subject: IPv6 kernel warning
Date: Fri, 20 Sep 2013 14:11:53 +0100
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While running v3.11 on my firewall, I saw this warning.  I'm not sure
what it means or what its implications are:

------------[ cut here ]------------
WARNING: CPU: 0 PID: 0 at /home/rmk/git/linux-rmk/net/ipv4/tcp_input.c:2711 tcp_fastretrans_alert+0x178/0x840()
Modules linked in: ipt_REJECT xt_multiport iptable_filter ipt_MASQUERADE xt_nat
xt_mark iptable_nat nf_nat_ipv4 nf_nat ip6table_mangle xt_LOG xt_limit nf_conntrack_ipv6 nf_defrag_ipv6 xt_state ip6table_filter pata_pcmcia libata scsi_mod 3c589_cs ide_gd_mod ide_cs ide_core sa1111_cs sa1100_cs sa11xx_base soc_common sa11x0_dma virt_dma usbcore usb_common
CPU: 0 PID: 0 Comm: swapper Not tainted 3.11.0+ #15
Backtrace:
[<c02111a8>] (dump_backtrace+0x0/0x114) from [<c02115a0>] (show_stack+0x18/0x1c) r6:c0520824 r5:00000009 r4:00000000
[<c0211588>] (show_stack+0x0/0x1c) from [<c04d65e0>] (dump_stack+0x20/0x28)
[<c04d65c0>] (dump_stack+0x0/0x28) from [<c021bfb0>] (warn_slowpath_common+0x68/0x88)
[<c021bf48>] (warn_slowpath_common+0x0/0x88) from [<c021bff4>] (warn_slowpath_null+0x24/0x28)
 r8:00000000 r7:00000001 r6:00000006 r5:00004320 r4:c11c6580
[<c021bfd0>] (warn_slowpath_null+0x0/0x28) from [<c04515bc>] (tcp_fastretrans_alert+0x178/0x840)
[<c0451444>] (tcp_fastretrans_alert+0x0/0x840) from [<c045273c>] (tcp_ack+0xa14/0xc18)
[<c0451d28>] (tcp_ack+0x0/0xc18) from [<c0453138>] (tcp_rcv_established+0x494/0x594)
[<c0452ca4>] (tcp_rcv_established+0x0/0x594) from [<c04a977c>] (tcp_v6_do_rcv+0xd0/0x428)
[<c04a96ac>] (tcp_v6_do_rcv+0x0/0x428) from [<c04a9e70>] (tcp_v6_rcv+0x340/0x63c)
[<c04a9b30>] (tcp_v6_rcv+0x0/0x63c) from [<c048b334>] (ip6_input_finish+0x214/0x3c4)
[<c048b120>] (ip6_input_finish+0x0/0x3c4) from [<c048ba60>] (ip6_input+0x64/0x74)
[<c048b9fc>] (ip6_input+0x0/0x74) from [<c048b564>] (ip6_rcv_finish+0x80/0x8c)
 r4:c1c9ee20
[<c048b4e4>] (ip6_rcv_finish+0x0/0x8c) from [<c048b994>] (ipv6_rcv+0x424/0x48c)
 r4:c1c9ee20
[<c048b570>] (ipv6_rcv+0x0/0x48c) from [<c0407624>] (__netif_receive_skb_core+0x618/0x688)
 r8:0000dd86 r7:00000000 r6:c11f6800 r5:c05ee6cc r4:c05f1b98
[<c040700c>] (__netif_receive_skb_core+0x0/0x688) from [<c040770c>] (__netif_receive_skb+0x78/0x80)
[<c0407694>] (__netif_receive_skb+0x0/0x80) from [<c04077a8>] (process_backlog+0x94/0x14c)
 r5:c06091e0 r4:c0609220
[<c0407714>] (process_backlog+0x0/0x14c) from [<c0407af4>] (net_rx_action+0x78/0x1ac)
[<c0407a7c>] (net_rx_action+0x0/0x1ac) from [<c021f500>] (__do_softirq+0xb4/0x198)
[<c021f44c>] (__do_softirq+0x0/0x198) from [<c021f90c>] (irq_exit+0x74/0xc8)
[<c021f898>] (irq_exit+0x0/0xc8) from [<c020f1ac>] (handle_IRQ+0x68/0x88)
 r4:0000000b
[<c020f144>] (handle_IRQ+0x0/0x88) from [<c0208210>] (asm_do_IRQ+0x10/0x14)
 r5:60000013 r4:c0246818
[<c0208200>] (asm_do_IRQ+0x0/0x14) from [<c0211fcc>] (__irq_svc+0x2c/0x98)
Exception stack(0xc05e7f54 to 0xc05e7f9c)
7f40:                                              00000000 00000000 00000000
7f60: 60000013 c05e6000 c06092a4 c05ee080 00000001 c0204000 6901b115 c05e0800
7f80: c05e7fb8 c05e7f9c c05e7f9c c020f348 c0246818 60000013 ffffffff
[<c0246794>] (cpu_startup_entry+0x0/0xe8) from [<c04d4d70>] (rest_init+0x64/0x7c)
 r7:c05f3940 r6:c0922200 r5:c0609340 r4:c05ee0c0
[<c04d4d0c>] (rest_init+0x0/0x7c) from [<c05c3acc>] (start_kernel+0x350/0x3ac)
[<c05c377c>] (start_kernel+0x0/0x3ac) from [<c0208040>] (0xc0208040)
---[ end trace ab55f0e3f592fa5e ]---