Le jeudi 06 mai 2010 à 08:40 +0200, Eric Dumazet a écrit :
quoted text > Le jeudi 06 mai 2010 à 03:01 +0200, Martín Ferrari a écrit :
> > Hi there,
> >
> > While working on my project that uses netns, I found another bug. This
> > one causes a "Kernel panic - not syncing: Fatal exception in
> > interrupt", and I can reproduce it in 2.6.33 and 2.6.34-rc5, but not
> > in 2.6.32. It dies during a call to __free_skb.
> > I tested this on my x86_64 laptop (2 cores) and on qemu. In qemu it
> > was not triggered until I asked it to emulate 2 cpus instead of one,
> > so it is probably a SMP-only issue.
> >
> > Scenario:
> >
> > I set up a number of network namespaces, each with two veths to netns
> > 1. In the main namespace I take those veths and bridge them in pairs,
> > to configure a linear topology; also I configure the netem qdisc to
> > simulate link delay.
> >
> > Once the network is set up, I run a client/server program to send UDP
> > packets from one end of the topology to the other. After a few seconds
> > of sending packets (not really deterministic) it panics.
> >
> > Note that I didn't experience this problem when using only 2
> > namespaces (so, no routing)
> >
> > below the dumps. These all come from the qemu, as I couldn't use
> > netconsole in the network at work, but I checked and the backtraces
> > were essentially the same
> >
> > First, two panics with 2.6.34, each one with a slightly different backtrace
> >
> > [ 65.272131] ------------[ cut here ]------------
> > [ 65.272135] kernel BUG at mm/slub.c:2846!
> > [ 65.272135] invalid opcode: 0000 [#1] SMP
> > [ 65.272135] last sysfs file: /sys/devices/virtual/net/lo/operstate
> > [ 65.272135] CPU 1
> > [ 65.272135] Modules linked in: sch_netem veth bridge stp netconsole
> > configfs loop parport_pc parport evdev tpm_tis tpm snd_pcm tpm_bios
> > snd_timer snd soundcore snd_page_alloc pcspkr psmouse serio_raw
> > i2c_piix4 button i2c_core processor ext3 jbd mbcache ide_cd_mod cdrom
> > ide_gd_mod ata_generic ata_piix libata 8139too scsi_mod floppy piix
> > 8139cp mii ide_core thermal thermal_sys [last unloaded: configfs]
> > [ 65.272135]
> > [ 65.272135] Pid: 1518, comm: udp-perf Not tainted 2.6.34-rc5 #1 /
> > [ 65.272135] RIP: 0010:[<ffffffff810e0d6b>] [<ffffffff810e0d6b>]
> > kfree+0x55/0xc6
> > [ 65.272135] RSP: 0018:ffff880001a23d90 EFLAGS: 00010246
> > [ 65.272135] RAX: 0100000000000000 RBX: ffff88007d6bc600 RCX: 0000000000012850
> > [ 65.272135] RDX: ffff88007d6bc600 RSI: 000000000000000e RDI: ffffea0001b6f610
> > [ 65.272135] RBP: ffff88007d6ae200 R08: ffff88007d6bc600 R09: ffffffffa0280690
> > [ 65.272135] R10: 0000000000000002 R11: ffff88007d6bc500 R12: ffffffff8123a77f
> > [ 65.272135] R13: 000000000000002b R14: ffff88007d39b600 R15: ffff88007d6bc600
> > [ 65.272135] FS: 00007f637c9dd6f0(0000) GS:ffff880001a20000(0000)
> > knlGS:0000000000000000
> > [ 65.272135] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b
> > [ 65.272135] CR2: 00000000009deaa0 CR3: 000000007d82d000 CR4: 00000000000006e0
> > [ 65.272135] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> > [ 65.272135] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
> > [ 65.272135] Process udp-perf (pid: 1518, threadinfo
> > ffff88007d92a000, task ffff88007e7ff810)
> > [ 65.272135] Stack:
> > [ 65.272135] ffff88007d6bc600 ffff88007d6bc600 0000000000000246
> > ffffffff8123a77f
> > [ 65.272135] <0> ffff880001a32860 ffffffff81241e01 ffffe8ffff623280
> > ffffe8ffff83ffc0
> > [ 65.272135] <0> ffff88007d6bc600 ffffffffa028057d 000000027d4c06c8
> > ffff88007d4c0600
> > [ 65.272135] Call Trace:
> > [ 65.272135] <IRQ>
> > [ 65.272135] [<ffffffff8123a77f>] ? __kfree_skb+0x11/0x7d
> > [ 65.272135] [<ffffffff81241e01>] ? netif_rx+0xe2/0xee
> > [ 65.272135] [<ffffffffa028057d>] ? veth_xmit+0x6e/0xad [veth]
> > [ 65.272135] [<ffffffff8124301f>] ? dev_hard_start_xmit+0x221/0x301
> > [ 65.272135] [<ffffffff81256d9a>] ? sch_direct_xmit+0x5b/0x15d
> > [ 65.272135] [<ffffffff81256f55>] ? __qdisc_run+0xb9/0xd8
> > [ 65.272135] [<ffffffff81240511>] ? net_tx_action+0xd6/0x149
> > [ 65.272135] [<ffffffff8104ba02>] ? __do_softirq+0xdd/0x19f
> > [ 65.272135] [<ffffffff8101e515>] ? lapic_next_event+0x18/0x1d
> > [ 65.272135] [<ffffffff810099dc>] ? call_softirq+0x1c/0x30
> > [ 65.272135] [<ffffffff8100b863>] ? do_softirq+0x3f/0x79
> > [ 65.272135] [<ffffffff8104b88e>] ? irq_exit+0x36/0x76
> > [ 65.272135] [<ffffffff8101f000>] ? smp_apic_timer_interrupt+0x86/0x94
> > [ 65.272135] [<ffffffff81009493>] ? apic_timer_interrupt+0x13/0x20
> > [ 65.272135] <EOI>
> > [ 65.272135] [<ffffffff8114c1ea>] ? cap_sk_getsecid+0x0/0x1
> > [ 65.272135] [<ffffffff812a0b0f>] ? __xfrm_lookup+0x2/0xb04
> > [ 65.272135] [<ffffffff81264b8d>] ? ip_route_output_flow+0x77/0x1cc
> > [ 65.272135] [<ffffffff812887c6>] ? udp_sendmsg+0x32d/0x5f3
> > [ 65.272135] [<ffffffff81009400>] ? irq_entries_start+0x3c0/0x400
> > [ 65.272135] [<ffffffff8128e112>] ? inet_sendmsg+0x53/0x58
> > [ 65.272135] [<ffffffff8123388d>] ? sock_sendmsg+0x83/0x9b
> > [ 65.272135] [<ffffffff8103a042>] ? pick_next_task_fair+0xca/0xd6
> > [ 65.272135] [<ffffffff812ef74a>] ? schedule+0x52b/0x593
> > [ 65.272135] [<ffffffff8100948e>] ? apic_timer_interrupt+0xe/0x20
> > [ 65.272135] [<ffffffff8100948e>] ? apic_timer_interrupt+0xe/0x20
> > [ 65.272135] [<ffffffff81185d4b>] ? _copy_from_user+0x1b/0x30
> > [ 65.272135] [<ffffffff8100765f>] ? __switch_to+0x1b5/0x2a6
> > [ 65.272135] [<ffffffff81232227>] ? copy_from_user+0x13/0x25
> > [ 65.272135] [<ffffffff812353cb>] ? sys_sendto+0xd7/0x117
> > [ 65.272135] [<ffffffff8103f7b1>] ? finish_task_switch+0x34/0xa1
> > [ 65.272135] [<ffffffff812ef74a>] ? schedule+0x52b/0x593
> > [ 65.272135] [<ffffffff8100948e>] ? apic_timer_interrupt+0xe/0x20
> > [ 65.272135] [<ffffffff81008ac2>] ? system_call_fastpath+0x16/0x1b
> > [ 65.272135] Code: 83 c3 08 48 83 3b 00 eb ec 48 83 fd 10 0f 86 84
> > 00 00 00 48 89 ef e8 f4 e2 ff ff 48 89 c7 48 8b 00 84 c0 78 13 66 a9
> > 00 c0 75 04 <0f> 0b eb fe 5b 5d 41 5c e9 fb 57 fd ff 48 8b 4c 24 18 4c
> > 8b 47
> > [ 65.272135] RIP [<ffffffff810e0d6b>] kfree+0x55/0xc6
> > [ 65.272135] RSP <ffff880001a23d90>
> > [ 65.385803] ---[ end trace 42d2fb5b94980ab5 ]---
> > [ 65.386337] Kernel panic - not syncing: Fatal exception in interrupt
> > [ 65.386943] Pid: 1518, comm: udp-perf Tainted: G D 2.6.34-rc5 #1
> > [ 65.387557] Call Trace:
> > [ 65.388011] <IRQ> [<ffffffff812eef9b>] ? panic+0x77/0xf7
> > [ 65.388729] [<ffffffff81046b88>] ? kmsg_dump+0xa6/0x13e
> > [ 65.389292] [<ffffffff8100c8c2>] ? oops_end+0xa7/0xb4
> > [ 65.389871] [<ffffffff8123a77f>] ? __kfree_skb+0x11/0x7d
> > [ 65.390441] [<ffffffff8100a695>] ? do_invalid_op+0x8b/0x95
> > [ 65.391032] [<ffffffff810e0d6b>] ? kfree+0x55/0xc6
> > [ 65.391587] [<ffffffffa026f301>] ?
> > br_nf_pre_routing_finish+0x0/0x25e [bridge]
> > [ 65.392512] [<ffffffffa026f301>] ?
> > br_nf_pre_routing_finish+0x0/0x25e [bridge]
> > [ 65.393399] [<ffffffff8100975b>] ? invalid_op+0x1b/0x20
> > [ 65.393978] [<ffffffff8123a77f>] ? __kfree_skb+0x11/0x7d
> > [ 65.394547] [<ffffffff810e0d6b>] ? kfree+0x55/0xc6
> > [ 65.395091] [<ffffffff8123a77f>] ? __kfree_skb+0x11/0x7d
> > [ 65.395668] [<ffffffff81241e01>] ? netif_rx+0xe2/0xee
> > [ 65.396438] [<ffffffffa028057d>] ? veth_xmit+0x6e/0xad [veth]
> > [ 65.397026] [<ffffffff8124301f>] ? dev_hard_start_xmit+0x221/0x301
> > [ 65.397640] [<ffffffff81256d9a>] ? sch_direct_xmit+0x5b/0x15d
> > [ 65.398222] [<ffffffff81256f55>] ? __qdisc_run+0xb9/0xd8
> > [ 65.398788] [<ffffffff81240511>] ? net_tx_action+0xd6/0x149
> > [ 65.399365] [<ffffffff8104ba02>] ? __do_softirq+0xdd/0x19f
> > [ 65.399935] [<ffffffff8101e515>] ? lapic_next_event+0x18/0x1d
> > [ 65.400560] [<ffffffff810099dc>] ? call_softirq+0x1c/0x30
> > [ 65.401125] [<ffffffff8100b863>] ? do_softirq+0x3f/0x79
> > [ 65.401708] [<ffffffff8104b88e>] ? irq_exit+0x36/0x76
> > [ 65.402267] [<ffffffff8101f000>] ? smp_apic_timer_interrupt+0x86/0x94
> > [ 65.402869] [<ffffffff81009493>] ? apic_timer_interrupt+0x13/0x20
> > [ 65.403463] <EOI> [<ffffffff8114c1ea>] ? cap_sk_getsecid+0x0/0x1
> > [ 65.404210] [<ffffffff812a0b0f>] ? __xfrm_lookup+0x2/0xb04
> > [ 65.404779] [<ffffffff81264b8d>] ? ip_route_output_flow+0x77/0x1cc
> > [ 65.405375] [<ffffffff812887c6>] ? udp_sendmsg+0x32d/0x5f3
> > [ 65.405945] [<ffffffff81009400>] ? irq_entries_start+0x3c0/0x400
> > [ 65.406534] [<ffffffff8128e112>] ? inet_sendmsg+0x53/0x58
> > [ 65.407102] [<ffffffff8123388d>] ? sock_sendmsg+0x83/0x9b
> > [ 65.407674] [<ffffffff8103a042>] ? pick_next_task_fair+0xca/0xd6
> > [ 65.408296] [<ffffffff812ef74a>] ? schedule+0x52b/0x593
> > [ 65.408854] [<ffffffff8100948e>] ? apic_timer_interrupt+0xe/0x20
> > [ 65.409468] [<ffffffff8100948e>] ? apic_timer_interrupt+0xe/0x20
> > [ 65.410084] [<ffffffff81185d4b>] ? _copy_from_user+0x1b/0x30
> > [ 65.410667] [<ffffffff8100765f>] ? __switch_to+0x1b5/0x2a6
> > [ 65.510031] [<ffffffff81232227>] ? copy_from_user+0x13/0x25
> > [ 65.510818] [<ffffffff812353cb>] ? sys_sendto+0xd7/0x117
> > [ 65.511608] [<ffffffff8103f7b1>] ? finish_task_switch+0x34/0xa1
> > [ 65.512465] [<ffffffff812ef74a>] ? schedule+0x52b/0x593
> > [ 65.513229] [<ffffffff8100948e>] ? apic_timer_interrupt+0xe/0x20
> > [ 65.514040] [<ffffffff81008ac2>] ? system_call_fastpath+0x16/0x1b
> >
> > [ 1438.042568] ------------[ cut here ]------------
> > [ 1438.043170] kernel BUG at mm/slub.c:2846!
> > [ 1438.043711] invalid opcode: 0000 [#1] SMP
> > [ 1438.044531] last sysfs file: /sys/devices/virtual/net/lo/operstate
> > [ 1438.045148] CPU 1
> > [ 1438.045350] Modules linked in: sch_netem veth bridge stp netconsole
> > configfs loop parport_pc tpm_tis tpm snd_pcm psmouse parport tpm_bios
> > snd_timer snd soundcore snd_page_alloc evdev pcspkr serio_raw
> > i2c_piix4 i2c_core button processor ext3 jbd mbcache ide_cd_mod cdrom
> > ide_gd_mod ata_generic ata_piix 8139too libata scsi_mod floppy 8139cp
> > mii thermal thermal_sys piix ide_core [last unloaded: scsi_wait_scan]
> > [ 1438.046215]
> > [ 1438.046215] Pid: 1476, comm: udp-perf Not tainted 2.6.34-rc5 #1 /
> > [ 1438.046215] RIP: 0010:[<ffffffff810e0d6b>] [<ffffffff810e0d6b>]
> > kfree+0x55/0xc6
> > [ 1438.046215] RSP: 0018:ffff880001a23d90 EFLAGS: 00010246
> > [ 1438.046215] RAX: 0100000000000000 RBX: ffff88007d882200 RCX: 0000000000012850
> > [ 1438.046215] RDX: ffff88007d882200 RSI: 000000000000000e RDI: ffffea0001b972a0
> > [ 1438.046215] RBP: ffff88007e20c000 R08: ffff88007d882200 R09: ffffffffa026c690
> > [ 1438.046215] R10: 0000000000000002 R11: ffff88007d882100 R12: ffffffff8123a77f
> > [ 1438.046215] R13: 0000000000000032 R14: ffff8800378e0700 R15: ffff88007d882200
> > [ 1438.046215] FS: 00007f1c1d07f6f0(0000) GS:ffff880001a20000(0000)
> > knlGS:0000000000000000
> > [ 1438.046215] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b
> > [ 1438.046215] CR2: 00007f6ea9e07310 CR3: 0000000037834000 CR4: 00000000000006e0
> > [ 1438.046215] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> > [ 1438.046215] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
> > [ 1438.046215] Process udp-perf (pid: 1476, threadinfo
> > ffff88007db0e000, task ffff8800379a2350)
> > [ 1438.046215] Stack:
> > [ 1438.046215] ffff88007d882200 ffff88007d882200 0000000000000246
> > ffffffff8123a77f
> > [ 1438.046215] <0> ffff880001a32860 ffffffff81241e01 ffffe8ffffa3f430
> > ffffe8ffffa3d180
> > [ 1438.046215] <0> ffff88007d882200 ffffffffa026c57d 0000000201a30500
> > ffff88007d171200
> > [ 1438.046215] Call Trace:
> > [ 1438.046215] <IRQ>
> > [ 1438.046215] [<ffffffff8123a77f>] ? __kfree_skb+0x11/0x7d
> > [ 1438.046215] [<ffffffff81241e01>] ? netif_rx+0xe2/0xee
> > [ 1438.046215] [<ffffffffa026c57d>] ? veth_xmit+0x6e/0xad [veth]
> > [ 1438.046215] [<ffffffff8124301f>] ? dev_hard_start_xmit+0x221/0x301
> > [ 1438.046215] [<ffffffff81256d9a>] ? sch_direct_xmit+0x5b/0x15d
> > [ 1438.046215] [<ffffffff81256f55>] ? __qdisc_run+0xb9/0xd8
> > [ 1438.046215] [<ffffffff81240511>] ? net_tx_action+0xd6/0x149
> > [ 1438.046215] [<ffffffff8104ba02>] ? __do_softirq+0xdd/0x19f
> > [ 1438.046215] [<ffffffff8101e515>] ? lapic_next_event+0x18/0x1d
> > [ 1438.046215] [<ffffffff810099dc>] ? call_softirq+0x1c/0x30
> > [ 1438.046215] [<ffffffff8100b863>] ? do_softirq+0x3f/0x79
> > [ 1438.046215] [<ffffffff8104b88e>] ? irq_exit+0x36/0x76
> > [ 1438.046215] [<ffffffff8101f000>] ? smp_apic_timer_interrupt+0x86/0x94
> > [ 1438.046215] [<ffffffff81009493>] ? apic_timer_interrupt+0x13/0x20
> > [ 1438.046215] <EOI>
> > [ 1438.046215] [<ffffffff81288499>] ? udp_sendmsg+0x0/0x5f3
> > [ 1438.046215] [<ffffffff8128850f>] ? udp_sendmsg+0x76/0x5f3
> > [ 1438.046215] [<ffffffff812889a7>] ? udp_sendmsg+0x50e/0x5f3
> > [ 1438.046215] [<ffffffff8123388d>] ? sock_sendmsg+0x83/0x9b
> > [ 1438.046215] [<ffffffff8103a042>] ? pick_next_task_fair+0xca/0xd6
> > [ 1438.046215] [<ffffffff812ef74a>] ? schedule+0x52b/0x593
> > [ 1438.046215] [<ffffffff8100948e>] ? apic_timer_interrupt+0xe/0x20
> > [ 1438.046215] [<ffffffff8100948e>] ? apic_timer_interrupt+0xe/0x20
> > [ 1438.046215] [<ffffffff8100948e>] ? apic_timer_interrupt+0xe/0x20
> > [ 1438.046215] [<ffffffff810e93ed>] ? fget_light+0x0/0xa1
> > [ 1438.046215] [<ffffffff81185e40>] ? copy_user_generic_string+0x30/0x40
> > [ 1438.046215] [<ffffffff81232227>] ? copy_from_user+0x13/0x25
> > [ 1438.046215] [<ffffffff812353cb>] ? sys_sendto+0xd7/0x117
> > [ 1438.046215] [<ffffffff8103f7b1>] ? finish_task_switch+0x34/0xa1
> > [ 1438.046215] [<ffffffff812ef74a>] ? schedule+0x52b/0x593
> > [ 1438.046215] [<ffffffff8100948e>] ? apic_timer_interrupt+0xe/0x20
> > [ 1438.046215] [<ffffffff81008ac2>] ? system_call_fastpath+0x16/0x1b
> > [ 1438.046215] Code: 83 c3 08 48 83 3b 00 eb ec 48 83 fd 10 0f 86 84
> > 00 00 00 48 89 ef e8 f4 e2 ff ff 48 89 c7 48 8b 00 84 c0 78 13 66 a9
> > 00 c0 75 04 <0f> 0b eb fe 5b 5d 41 5c e9 fb 57 fd ff 48 8b 4c 24 18 4c
> > 8b 47
> > [ 1438.046215] RIP [<ffffffff810e0d6b>] kfree+0x55/0xc6
> > [ 1438.046215] RSP <ffff880001a23d90>
> > [ 1438.102706] ---[ end trace ab36062dcf233d6a ]---
> > [ 1438.103251] Kernel panic - not syncing: Fatal exception in interrupt
> > [ 1438.103912] Pid: 1476, comm: udp-perf Tainted: G D 2.6.34-rc5 #1
> > [ 1438.104563] Call Trace:
> > [ 1438.105017] <IRQ> [<ffffffff812eef9b>] ? panic+0x77/0xf7
> > [ 1438.105718] [<ffffffff81046b88>] ? kmsg_dump+0xa6/0x13e
> > [ 1438.106293] [<ffffffff8100c8c2>] ? oops_end+0xa7/0xb4
> > [ 1438.106866] [<ffffffff8123a77f>] ? __kfree_skb+0x11/0x7d
> > [ 1438.107451] [<ffffffff8100a695>] ? do_invalid_op+0x8b/0x95
> > [ 1438.108036] [<ffffffff810e0d6b>] ? kfree+0x55/0xc6
> > [ 1438.108799] [<ffffffffa025b301>] ?
> > br_nf_pre_routing_finish+0x0/0x25e [bridge]
> > [ 1438.109699] [<ffffffffa025b301>] ?
> > br_nf_pre_routing_finish+0x0/0x25e [bridge]
> > [ 1438.110604] [<ffffffff8100975b>] ? invalid_op+0x1b/0x20
> > [ 1438.111172] [<ffffffff8123a77f>] ? __kfree_skb+0x11/0x7d
> > [ 1438.111753] [<ffffffff810e0d6b>] ? kfree+0x55/0xc6
> > [ 1438.112359] [<ffffffff8123a77f>] ? __kfree_skb+0x11/0x7d
> > [ 1438.112952] [<ffffffff81241e01>] ? netif_rx+0xe2/0xee
> > [ 1438.113527] [<ffffffffa026c57d>] ? veth_xmit+0x6e/0xad [veth]
> > [ 1438.114123] [<ffffffff8124301f>] ? dev_hard_start_xmit+0x221/0x301
> > [ 1438.114734] [<ffffffff81256d9a>] ? sch_direct_xmit+0x5b/0x15d
> > [ 1438.115334] [<ffffffff81256f55>] ? __qdisc_run+0xb9/0xd8
> > [ 1438.115912] [<ffffffff81240511>] ? net_tx_action+0xd6/0x149
> > [ 1438.116544] [<ffffffff8104ba02>] ? __do_softirq+0xdd/0x19f
> > [ 1438.117128] [<ffffffff8101e515>] ? lapic_next_event+0x18/0x1d
> > [ 1438.117732] [<ffffffff810099dc>] ? call_softirq+0x1c/0x30
> > [ 1438.118420] [<ffffffff8100b863>] ? do_softirq+0x3f/0x79
> > [ 1438.119066] [<ffffffff8104b88e>] ? irq_exit+0x36/0x76
> > [ 1438.147879] [<ffffffff8101f000>] ? smp_apic_timer_interrupt+0x86/0x94
> > [ 1438.148615] [<ffffffff81009493>] ? apic_timer_interrupt+0x13/0x20
> > [ 1438.149294] <EOI> [<ffffffff81288499>] ? udp_sendmsg+0x0/0x5f3
> > [ 1438.150101] [<ffffffff8128850f>] ? udp_sendmsg+0x76/0x5f3
> > [ 1438.150681] [<ffffffff812889a7>] ? udp_sendmsg+0x50e/0x5f3
> > [ 1438.151276] [<ffffffff8123388d>] ? sock_sendmsg+0x83/0x9b
> > [ 1438.151853] [<ffffffff8103a042>] ? pick_next_task_fair+0xca/0xd6
> > [ 1438.152508] [<ffffffff812ef74a>] ? schedule+0x52b/0x593
> > [ 1438.153078] [<ffffffff8100948e>] ? apic_timer_interrupt+0xe/0x20
> > [ 1438.153687] [<ffffffff8100948e>] ? apic_timer_interrupt+0xe/0x20
> > [ 1438.154295] [<ffffffff8100948e>] ? apic_timer_interrupt+0xe/0x20
> > [ 1438.154902] [<ffffffff810e93ed>] ? fget_light+0x0/0xa1
> > [ 1438.155477] [<ffffffff81185e40>] ? copy_user_generic_string+0x30/0x40
> > [ 1438.156097] [<ffffffff81232227>] ? copy_from_user+0x13/0x25
> > [ 1438.156720] [<ffffffff812353cb>] ? sys_sendto+0xd7/0x117
> > [ 1438.157376] [<ffffffff8103f7b1>] ? finish_task_switch+0x34/0xa1
> > [ 1438.157970] [<ffffffff812ef74a>] ? schedule+0x52b/0x593
> > [ 1438.158557] [<ffffffff8100948e>] ? apic_timer_interrupt+0xe/0x20
> > [ 1438.159153] [<ffffffff81008ac2>] ? system_call_fastpath+0x16/0x1b
> >
> > ------------
> >
> > Finally, a panic in 2.6.33. Note that the line in wioch BUG is
> > triggered is different
> >
> > [ 102.442815] ------------[ cut here ]------------
> > [ 102.443433] kernel BUG at
> > /build/mattems-linux-2.6_2.6.33-1~experimental.4-amd64-ieqSsa/linux-2.6-2.6.33-1~experimental.4/debian/build/source_amd64_none/mm/slub.c:2969!
> > [ 102.444874] invalid opcode: 0000 [#1] SMP
> > [ 102.444958] last sysfs file: /sys/devices/virtual/net/lo/operstate
> > [ 102.444958] CPU 0
> > [ 102.444958] Pid: 4, comm: ksoftirqd/0 Not tainted 2.6.33-2-amd64 #1 /
> > [ 102.444958] RIP: 0010:[<ffffffff810e1e2c>] [<ffffffff810e1e2c>]
> > kfree+0x55/0xcb
> > [ 102.444958] RSP: 0018:ffff880001a03df8 EFLAGS: 00010246
> > [ 102.444958] RAX: 0100000000000000 RBX: ffff88007e439000 RCX: 0000000000012d70
> > [ 102.444958] RDX: 000000000000006a RSI: ffffea0001b76a70 RDI: ffffea0000c1a328
> > [ 102.444958] RBP: ffff880037533c00 R08: ffff88007e21e500 R09: ffffffff8162bbe0
> > [ 102.444958] R10: 000000037e439e00 R11: ffff88007e439e00 R12: ffffffff81239cf2
> > [ 102.444958] R13: 000000000000006a R14: ffff88007efb3000 R15: ffff88007e21e500
> > [ 102.444958] FS: 0000000000000000(0000) GS:ffff880001a00000(0000)
> > knlGS:0000000000000000
> > [ 102.444958] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b
> > [ 102.444958] CR2: 00007fc8e25cd0f0 CR3: 000000007d088000 CR4: 00000000000006f0
> > [ 102.444958] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> > [ 102.444958] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
> > [ 102.444958] Process ksoftirqd/0 (pid: 4, threadinfo
> > ffff88007fb78000, task ffff88007fb61500)
> > [ 102.444958] Stack:
> > [ 102.444958] ffff88007e439000 ffff88007e439000 0000000000000246
> > ffffffff81239cf2
> > [ 102.444958] <0> ffff880001a12d80 ffffffff8124125d ffffe8ffff818190
> > ffffe8ffff815ee0
> > [ 102.444958] <0> ffff88007e439000 ffffffffa025254b ffff880001a10010
> > ffff88007ef95200
> > [ 102.444958] Call Trace:
> > [ 102.444958] <IRQ>
> > [ 102.444958] [<ffffffff81239cf2>] ? __kfree_skb+0x11/0x7d
> > [ 102.444958] [<ffffffff8124125d>] ? netif_rx+0xe2/0xee
> > [ 102.444958] [<ffffffffa025254b>] ? veth_xmit+0x6e/0xad [veth]
> > [ 102.444958] [<ffffffff8124243a>] ? dev_hard_start_xmit+0x221/0x2dc
> > [ 102.444958] [<ffffffff81255514>] ? sch_direct_xmit+0x5b/0x15d
> > [ 102.444958] [<ffffffff812556cf>] ? __qdisc_run+0xb9/0xda
> > [ 102.444958] [<ffffffff8123fa99>] ? net_tx_action+0xd6/0x149
> > [ 102.444958] [<ffffffff8104c918>] ? __do_softirq+0xdd/0x1a1
> > [ 102.444958] [<ffffffff810099dc>] ? call_softirq+0x1c/0x30
> > [ 102.444958] <EOI>
> > [ 102.444958] [<ffffffff8100b85f>] ? do_softirq+0x3f/0x79
> > [ 102.444958] [<ffffffff8104c504>] ? run_ksoftirqd+0x6a/0x118
> > [ 102.444958] [<ffffffff8104c49a>] ? run_ksoftirqd+0x0/0x118
> > [ 102.444958] [<ffffffff8105ee99>] ? kthread+0x79/0x81
> > [ 102.444958] [<ffffffff810098e4>] ? kernel_thread_helper+0x4/0x10
> > [ 102.444958] [<ffffffff8105ee20>] ? kthread+0x0/0x81
> > [ 102.444958] [<ffffffff810098e0>] ? kernel_thread_helper+0x0/0x10
> > [ 102.444958] Code: 83 c3 08 48 83 3b 00 eb ec 48 83 fd 10 0f 86 89
> > 00 00 00 48 89 ef e8 f0 e6 ff ff 48 89 c7 48 8b 00 84 c0 78 13 66 a9
> > 00 c0 75 04 <0f> 0b eb fe 5b 5d 41 5c e9 45 5a fd ff 48 8b 4c 24 18 4c
> > 8b 4f
> > [ 102.444958] RIP [<ffffffff810e1e2c>] kfree+0x55/0xcb
> > [ 102.444958] RSP <ffff880001a03df8>
> > [ 102.484000] ---[ end trace b1157390d40df1cb ]---
> > [ 102.485018] Kernel panic - not syncing: Fatal exception in interrupt
> > [ 102.485647] Pid: 4, comm: ksoftirqd/0 Tainted: G D 2.6.33-2-amd64 #1
> > [ 102.486630] Call Trace:
> > [ 102.487112] <IRQ> [<ffffffff812ec605>] ? panic+0x86/0x14b
> > [ 102.487870] [<ffffffff8104c799>] ? irq_exit+0x48/0x76
> > [ 102.488474] [<ffffffff812ee893>] ? ret_from_intr+0x0/0x11
> > [ 102.489068] [<ffffffff810478c0>] ? kmsg_dump+0xa6/0x13e
> > [ 102.489661] [<ffffffff8100c89a>] ? oops_end+0xa7/0xb4
> > [ 102.490245] [<ffffffff81239cf2>] ? __kfree_skb+0x11/0x7d
> > [ 102.490836] [<ffffffff8100a690>] ? do_invalid_op+0x8b/0x95
> > [ 102.491436] [<ffffffff810e1e2c>] ? kfree+0x55/0xcb
> > [ 102.492020] [<ffffffffa0244aee>] ?
> > br_nf_pre_routing_finish+0x284/0x2a6 [bridge]
> > [ 102.492942] [<ffffffffa024486a>] ?
> > br_nf_pre_routing_finish+0x0/0x2a6 [bridge]
> > [ 102.493857] [<ffffffff8125f204>] ? nf_hook_slow+0x62/0xc3
> > [ 102.523082] [<ffffffffa024486a>] ?
> > br_nf_pre_routing_finish+0x0/0x2a6 [bridge]
> > [ 102.524008] [<ffffffff8100975b>] ? invalid_op+0x1b/0x20
> > [ 102.524631] [<ffffffff81239cf2>] ? __kfree_skb+0x11/0x7d
> > [ 102.525225] [<ffffffff810e1e2c>] ? kfree+0x55/0xcb
> > [ 102.525795] [<ffffffff810e1e1c>] ? kfree+0x45/0xcb
> > [ 102.526402] [<ffffffff81239cf2>] ? __kfree_skb+0x11/0x7d
> > [ 102.526992] [<ffffffff8124125d>] ? netif_rx+0xe2/0xee
> > [ 102.527576] [<ffffffffa025254b>] ? veth_xmit+0x6e/0xad [veth]
> > [ 102.528199] [<ffffffff8124243a>] ? dev_hard_start_xmit+0x221/0x2dc
> > [ 102.528821] [<ffffffff81255514>] ? sch_direct_xmit+0x5b/0x15d
> > [ 102.529429] [<ffffffff812556cf>] ? __qdisc_run+0xb9/0xda
> > [ 102.530018] [<ffffffff8123fa99>] ? net_tx_action+0xd6/0x149
> > [ 102.530618] [<ffffffff8104c918>] ? __do_softirq+0xdd/0x1a1
> > [ 102.531214] [<ffffffff810099dc>] ? call_softirq+0x1c/0x30
> > [ 102.531804] <EOI> [<ffffffff8100b85f>] ? do_softirq+0x3f/0x79
> > [ 102.532572] [<ffffffff8104c504>] ? run_ksoftirqd+0x6a/0x118
> > [ 102.533169] [<ffffffff8104c49a>] ? run_ksoftirqd+0x0/0x118
> > [ 102.533764] [<ffffffff8105ee99>] ? kthread+0x79/0x81
> > [ 102.534340] [<ffffffff810098e4>] ? kernel_thread_helper+0x4/0x10
> > [ 102.534954] [<ffffffff8105ee20>] ? kthread+0x0/0x81
> > [ 102.535526] [<ffffffff810098e0>] ? kernel_thread_helper+0x0/0x10
> >
>
> Could you please try following patch ?
>
> Thanks
>
> [PATCH] veth: Dont kfree_skb() after dev_forward_skb()
>
> In case of congestion, dev_forward_skb() already free the skb
>
> Reported-by: Martín Ferrari <martin.ferrari@gmail.com>
> Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
> ---
> diff --git a/drivers/net/veth.c b/drivers/net/veth.c
> index f9f0730..5ec542d 100644
> --- a/drivers/net/veth.c
> +++ b/drivers/net/veth.c
> @@ -187,7 +187,6 @@ tx_drop:
> return NETDEV_TX_OK;
>
> rx_drop:
> - kfree_skb(skb);
> rcv_stats->rx_dropped++;
> return NETDEV_TX_OK;
> }
>
Hmm, scratch that one, I'll resubmit a proper fix in few minutes
(We must change dev_forward_skb() too)
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