Bridge code Oops with 2.6.14.2 (was: Re: [uml-devel] RE: [uml-user] guest soft lockup after mounting root fs in skasmode)

From: Blaisorblade
Date: Thu Dec 29 2005 - 09:54:37 EST


On Tuesday 27 December 2005 22:38, Brock, Anthony - NET wrote:
> In fact, one of my production servers developed a rather serious issue
> when I upgraded the host kernel from 2.6.13.2 to 2.6.14.2 (both using
> SKAS3-v8.2). The host server would "freeze" hard when shutting down the
> guest instances (no network, console, etc). The issue disappeared when I
> reverted the host back to 2.6.13.2.

> Eventually I traced it back to an instance that was still running a
> 2.6.7 guest kernel. It triggered either during shutdown or within 0-5
> seconds after the instance was "killed" (the guest kernel wouldn't exit
> cleanly). The issue disappeared once I upgraded it to a more recent
> version. Unfortunately, only one of the "freezes" dumped any information
> (see below). Every other "freeze" resulted in a non-responsive system
> where I had to power-cycle to recover.

> So, either SKAS3, the tuntap device, network bridges, or some other host
> component associated with UML instances still has some issues.

The components executing, in the stack trace below, are the network driver,
which seems e100 driver, in NAPI (i.e. polling) mode, which is used for high
network traffic only, normally, and the bridge code.

In the thread

[uml-user] Kernel panic when using NS-2 and UML//TAP devices/ebtables

Fuad Abinader Jr, which I CC:ed on this mail, reports another crash (a
different one) coming from the use of bridge code (in that case, a BUG_ON
triggering).

I don't know if there is any association between them, however it seems that
the bridge code is showing more than one instability.

I can't help more, however - the next step is filing a bug to network
developers, upstream. For now I'm CC:ing LKML.

> Unable to handle kernel NULL pointer dereference at virtual address
> 00000000
> printing eip:
> f8be14f4
> *pde = 00000000
> Oops: 0000 [#1]
> SMP
> Modules linked in: autofs4 tun ipv6 bridge floppy pcspkr hw_random
> i2c_amd8111 generic amd74xx shpchp pci_hotplug ohci_hcd usbcore raid1
> md_mod dm_mod rtc w83627hf eeprom lm85 hwmon_vid i2c_isa i2c_amd756
> i2c_core tg3 e100 mii psmouse ide_generic ide_disk ide_cd cdrom ide_core
> unix
> CPU: 1
> EIP: 0060:[<f8be14f4>] Not tainted VLI
> EFLAGS: 00010287 (2.6.14.2-skas3-v8.2)
> EIP is at br_nf_forward_ip+0xa2/0x16a [bridge]
> eax: 00000000 ebx: d7b59dc0 ecx: ea4a5380 edx: 00000080
> esi: 00000002 edi: 00000002 ebp: f8bdbdb7 esp: e172bcc8
> ds: 007b es: 007b ss: 0068
> Process linux-2.6.7-02- (pid: 4049, threadinfo=e172a000 task=e99ed550)
> Stack: 80000000 c03e7350 c02d44e7 00000002 e172bd58 f8be1334 80000000
> ea4a5380
> e172bd40 80000000 c03e7350 c02d44e7 00000002 e172bd7c f2641000
> efd7e800
> f8bdbdb7 00000002 e172bd7c c03e7350 f8bdbdb7 c02d4564 c03e7350
> e172bd7c
> Call Trace:
> [<c02d44e7>] nf_iterate+0x66/0x8a
> [<f8be1334>] br_nf_forward_finish+0x0/0x11e [bridge]
> [<c02d44e7>] nf_iterate+0x66/0x8a
> [<f8bdbdb7>] br_forward_finish+0x0/0x6b [bridge]
> [<f8bdbdb7>] br_forward_finish+0x0/0x6b [bridge]
> [<c02d4564>] nf_hook_slow+0x59/0x10e
> [<f8bdbdb7>] br_forward_finish+0x0/0x6b [bridge]
> [<f8bdbefa>] __br_forward+0x63/0x7c [bridge]
> [<f8bdbdb7>] br_forward_finish+0x0/0x6b [bridge]
> [<f8bdc11b>] br_flood_forward+0x27/0x2c [bridge]
> [<f8bdbe97>] __br_forward+0x0/0x7c [bridge]
> [<f8bdcb1b>] br_handle_frame_finish+0x11b/0x137 [bridge]
> [<f8be094c>] br_nf_pre_routing_finish+0x1a6/0x36b [bridge]
> [<f8bdca00>] br_handle_frame_finish+0x0/0x137 [bridge]
> [<f8be07a6>] br_nf_pre_routing_finish+0x0/0x36b [bridge]
> [<f8be07a6>] br_nf_pre_routing_finish+0x0/0x36b [bridge]
> [<c02d4564>] nf_hook_slow+0x59/0x10e
> [<f8be07a6>] br_nf_pre_routing_finish+0x0/0x36b [bridge]
> [<f8bdca00>] br_handle_frame_finish+0x0/0x137 [bridge]
> [<f8be11a6>] br_nf_pre_routing+0x332/0x457 [bridge]
> [<f8be07a6>] br_nf_pre_routing_finish+0x0/0x36b [bridge]
> [<c02d44e7>] nf_iterate+0x66/0x8a
> [<f8bdca00>] br_handle_frame_finish+0x0/0x137 [bridge]
> [<f8bdca00>] br_handle_frame_finish+0x0/0x137 [bridge]
> [<c02d4564>] nf_hook_slow+0x59/0x10e
> [<f8bdca00>] br_handle_frame_finish+0x0/0x137 [bridge]
> [<f8bdccec>] br_handle_frame+0x1b5/0x229 [bridge]
> [<f8bdca00>] br_handle_frame_finish+0x0/0x137 [bridge]
> [<c027e6e9>] netif_receive_skb+0x1af/0x334
> [<f8a74bf5>] e100_poll+0x1cf/0x70c [e100]
> [<c027ea36>] net_rx_action+0xc1/0x197
> [<c01206a2>] __do_softirq+0x72/0xdd
> [<c0120740>] do_softirq+0x33/0x35
> [<c0104e7e>] do_IRQ+0x1e/0x24
> [<c0103772>] common_interrupt+0x1a/0x20
> Code: c1 e2 06 8d 82 90 71 3e c0 3b 82 90 71 3e c0 74 58 c7 44 24 18 00
> 00 00 80 c7 44 24 14 34 13 be f8 8b 44 24 3c 8b 80 ec 02 00 00 <8b> 00
> 8b 40 0c 89 44 24 10 8b 44 24 38 8b 80 ec 02 00 00 8b 00
>
>
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--
Inform me of my mistakes, so I can keep imitating Homer Simpson's "Doh!".
Paolo Giarrusso, aka Blaisorblade (Skype ID "PaoloGiarrusso", ICQ 215621894)
http://www.user-mode-linux.org/~blaisorblade


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