Message-ID: <4D6B634E.9090801@univ-nantes.fr>
Date:	Mon, 28 Feb 2011 09:56:46 +0100
From:	Jean-Philippe Menil <jean-philippe.menil@...v-nantes.fr>
To:	"Michael S. Tsirkin" <mst@...hat.com>
CC:	kvm@...r.kernel.org, netdev@...r.kernel.org,
	virtualization@...ts.linux-foundation.org
Subject: Re: Bug inkvm_set_irq

Le 27/02/2011 18:00, Michael S. Tsirkin a écrit :
> On Fri, Feb 25, 2011 at 10:07:22AM +0100, Jean-Philippe Menil wrote:
>> Hi,
>>
>> Each time i try tou use vhost_net, i'm facing a kernel bug.
>> I do a "modprobe vhost_net", and start guest whith vhost=on.
>>
>> Following is a trace with a kernel 2.6.37, but  i had the same
>> problem with 2.6.36 (cf https://lkml.org/lkml/2010/11/30/29).
> 2.6.36 had a theorectical race that could explain this,
> but it should be ok in 2.6.37.
>
>> The bug only occurs whith vhost_net charged, so i don't know if this
>> is a bug in kvm module code or in the vhost_net code.
> It could be a bug in eventfd which is the interface
> used by both kvm and vhost_net.
> Just for fun, you can try 3.6.38 - eventfd code has been changed
> a lot in 2.6.38 and if it does not trigger there
> it's a hint that irqfd is the reason.
>
>> Feb 23 13:56:19 ayrshire.u06.univ-nantes.prive kernel: [
>> 685.243100] BUG: unable to handle kernel paging request at
>> 0000000000002458
>> Feb 23 13:56:19 ayrshire.u06.univ-nantes.prive kernel: [
>> 685.243250] IP: [<ffffffffa041aa8a>] kvm_set_irq+0x2a/0x130 [kvm]
>
> Could you run markup_oops/ ksymoops on this please?
> As far as I can see kvm_set_irq can only get a wrong
> kvm pointer. Unless there's some general memory corruption,
> I'd guess
>
> You can also try comparing the irqfd->kvm pointer in
> kvm_irqfd_assign irqfd_wakeup and kvm_set_irq in
> virt/kvm/eventfd.c.
>
>> Feb 23 13:56:19 ayrshire.u06.univ-nantes.prive kernel: [
>> 685.243378] PGD 45d363067 PUD 45e77a067 PMD 0
>> Feb 23 13:56:19 ayrshire.u06.univ-nantes.prive kernel: [
>> 685.243556] Oops: 0000 [#1] SMP
>> Feb 23 13:56:19 ayrshire.u06.univ-nantes.prive kernel: [
>> 685.243692] last sysfs file:
>> /sys/devices/pci0000:00/0000:00:0d.0/0000:05:00.0/0000:06:00.0/irq
>> Feb 23 13:56:19 ayrshire.u06.univ-nantes.prive kernel: [  685.243777] CPU 0
>> Feb 23 13:56:19 ayrshire.u06.univ-nantes.prive kernel: [
>> 685.243820] Modules linked in: vhost_net macvtap macvlan tun
>> powernow_k8 mperf cpufreq_userspace cpufreq_stats cpufreq_powersave
>> cpufreq_ondemand fre
>> q_table cpufreq_conservative fuse xt_physdev ip6t_LOG
>> ip6table_filter ip6_tables ipt_LOG xt_multiport xt_limit xt_tcpudp
>> xt_state iptable_filter ip_tables x_tables nf_conntrack_tftp
>> nf_conntrack_ftp nf_connt
>> rack_ipv4 nf_defrag_ipv4 8021q bridge stp ext2 mbcache
>> dm_round_robin dm_multipath nf_conntrack_ipv6 nf_conntrack
>> nf_defrag_ipv6 kvm_amd kvm ipv6 snd_pcm snd_timer snd soundcore
>> snd_page_alloc tpm_tis tpm ps
>> mouse dcdbas tpm_bios processor i2c_nforce2 shpchp pcspkr ghes
>> serio_raw joydev evdev pci_hotplug i2c_core hed button thermal_sys
>> xfs exportfs dm_mod sg sr_mod cdrom usbhid hid usb_storage ses
>> sd_mod enclosu
>> re megaraid_sas ohci_hcd lpfc scsi_transport_fc scsi_tgt bnx2
>> scsi_mod ehci_hcd [last unloaded: scsi_wait_scan]
>> Feb 23 13:56:19 ayrshire.u06.univ-nantes.prive kernel: [  685.246123]
>> Feb 23 13:56:19 ayrshire.u06.univ-nantes.prive kernel: [
>> 685.246123] Pid: 10, comm: kworker/0:1 Not tainted
>> 2.6.37-dsiun-110105 #17 0K543T/PowerEdge M605
>> Feb 23 13:56:19 ayrshire.u06.univ-nantes.prive kernel: [
>> 685.246123] RIP: 0010:[<ffffffffa041aa8a>]  [<ffffffffa041aa8a>]
>> kvm_set_irq+0x2a/0x130 [kvm]
>> Feb 23 13:56:19 ayrshire.u06.univ-nantes.prive kernel: [
>> 685.246123] RSP: 0018:ffff88045fc89d30  EFLAGS: 00010246
>> Feb 23 13:56:19 ayrshire.u06.univ-nantes.prive kernel: [
>> 685.246123] RAX: 0000000000000000 RBX: 000000000000001a RCX:
>> 0000000000000001
>> Feb 23 13:56:19 ayrshire.u06.univ-nantes.prive kernel: [
>> 685.246123] RDX: 0000000000000000 RSI: 0000000000000000 RDI:
>> 0000000000000000
>> Feb 23 13:56:19 ayrshire.u06.univ-nantes.prive kernel: [
>> 685.246123] RBP: 0000000000000000 R08: 0000000000000001 R09:
>> ffff880856a91e48
>> Feb 23 13:56:19 ayrshire.u06.univ-nantes.prive kernel: [
>> 685.246123] R10: 0000000000000000 R11: 00000000ffffffff R12:
>> 0000000000000000
>> Feb 23 13:56:19 ayrshire.u06.univ-nantes.prive kernel: [
>> 685.246123] R13: 0000000000000001 R14: 0000000000000000 R15:
>> 0000000000000000
>> Feb 23 13:56:19 ayrshire.u06.univ-nantes.prive kernel: [
>> 685.246123] FS:  00007f617986c710(0000) GS:ffff88007f800000(0000)
>> knlGS:0000000000000000
>> Feb 23 13:56:19 ayrshire.u06.univ-nantes.prive kernel: [
>> 685.246123] CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
>> Feb 23 13:56:19 ayrshire.u06.univ-nantes.prive kernel: [
>> 685.246123] CR2: 0000000000002458 CR3: 000000045d197000 CR4:
>> 00000000000006f0
>> Feb 23 13:56:19 ayrshire.u06.univ-nantes.prive kernel: [
>> 685.246123] DR0: 0000000000000000 DR1: 0000000000000000 DR2:
>> 0000000000000000
>> Feb 23 13:56:19 ayrshire.u06.univ-nantes.prive kernel: [
>> 685.246123] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7:
>> 0000000000000400
>> Feb 23 13:56:19 ayrshire.u06.univ-nantes.prive kernel: [
>> 685.246123] Process kworker/0:1 (pid: 10, threadinfo
>> ffff88045fc88000, task ffff88085fc53c30)
>> Feb 23 13:56:19 ayrshire.u06.univ-nantes.prive kernel: [  685.246123] Stack:
>> Feb 23 13:56:19 ayrshire.u06.univ-nantes.prive kernel: [
>> 685.246123]  ffff88045fc89fd8 00000000000119c0 ffff88045fc88010
>> ffff88085fc53ee8
>> Feb 23 13:56:19 ayrshire.u06.univ-nantes.prive kernel: [
>> 685.246123]  ffff88045fc89fd8 ffff88085fc53ee0 ffff88085fc53c30
>> 00000000000119c0
>> Feb 23 13:56:19 ayrshire.u06.univ-nantes.prive kernel: [
>> 685.246123]  00000000000119c0 ffffffff8137f7ce ffff88007f80df40
>> 00000000ffffffff
>> Feb 23 13:56:19 ayrshire.u06.univ-nantes.prive kernel: [
>> 685.246123] Call Trace:
>> Feb 23 13:56:19 ayrshire.u06.univ-nantes.prive kernel: [
>> 685.246123]  [<ffffffff8137f7ce>] ? common_interrupt+0xe/0x13
>> Feb 23 13:56:19 ayrshire.u06.univ-nantes.prive kernel: [
>> 685.246123]  [<ffffffffa041bc30>] ? irqfd_inject+0x0/0x50 [kvm]
>> Feb 23 13:56:19 ayrshire.u06.univ-nantes.prive kernel: [
>> 685.246123]  [<ffffffffa041bc57>] ? irqfd_inject+0x27/0x50 [kvm]
>> Feb 23 13:56:19 ayrshire.u06.univ-nantes.prive kernel: [
>> 685.246123]  [<ffffffffa041bc30>] ? irqfd_inject+0x0/0x50 [kvm]
>> Feb 23 13:56:19 ayrshire.u06.univ-nantes.prive kernel: [
>> 685.246123]  [<ffffffff8106b6f2>] ? process_one_work+0x112/0x460
>> Feb 23 13:56:19 ayrshire.u06.univ-nantes.prive kernel: [
>> 685.246123]  [<ffffffff8106be25>] ? worker_thread+0x145/0x410
>> Feb 23 13:56:19 ayrshire.u06.univ-nantes.prive kernel: [
>> 685.246123]  [<ffffffff8103a3d0>] ? __wake_up_common+0x50/0x80
>> Feb 23 13:56:19 ayrshire.u06.univ-nantes.prive kernel: [
>> 685.246123]  [<ffffffff8106bce0>] ? worker_thread+0x0/0x410
>> Feb 23 13:56:19 ayrshire.u06.univ-nantes.prive kernel: [
>> 685.246123]  [<ffffffff8106bce0>] ? worker_thread+0x0/0x410
>> Feb 23 13:56:19 ayrshire.u06.univ-nantes.prive kernel: [
>> 685.246123]  [<ffffffff8106f786>] ? kthread+0x96/0xa0
>> Feb 23 13:56:19 ayrshire.u06.univ-nantes.prive kernel: [
>> 685.246123]  [<ffffffff81003ce4>] ? kernel_thread_helper+0x4/0x10
>> Feb 23 13:56:19 ayrshire.u06.univ-nantes.prive kernel: [
>> 685.246123]  [<ffffffff8106f6f0>] ? kthread+0x0/0xa0
>> Feb 23 13:56:19 ayrshire.u06.univ-nantes.prive kernel: [
>> 685.246123]  [<ffffffff81003ce0>] ? kernel_thread_helper+0x0/0x10
>> Feb 23 13:56:19 ayrshire.u06.univ-nantes.prive kernel: [
>> 685.246123] Code: ff 41 57 41 89 f7 41 56 41 55 41 89 cd 41 54 49 89
>> fc 55 53 89 d3 48 81 ec 98 00 00 00 8b 15 c6 79 03 00 85 d2 0f 85 c4
>> 00 00 00<4
>> 9>  8b 84 24 58 24 00 00 3b 98 28 01 00 00 73 5e 89 db 48 8b 84
>> Feb 23 13:56:19 ayrshire.u06.univ-nantes.prive kernel: [
>> 685.246123] RIP  [<ffffffffa041aa8a>] kvm_set_irq+0x2a/0x130 [kvm]
>> Feb 23 13:56:19 ayrshire.u06.univ-nantes.prive kernel: [
>> 685.246123]  RSP<ffff88045fc89d30>
>> Feb 23 13:56:19 ayrshire.u06.univ-nantes.prive kernel: [
>> 685.246123] CR2: 0000000000002458
>>
>>
>> If someone can help me, on how to solve this.
>>
>> Regards.
>> _______________________________________________
>> Virtualization mailing list
>> Virtualization@...ts.linux-foundation.org
>> https://lists.linux-foundation.org/mailman/listinfo/virtualization
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Hi,

thanks for your response.

This is what markup_oops.pl return me:
"No matching code found "

So this is not a vhost_net bug, or my oops is incomplete and markup_oops 
can't find the good vma offset.

I will try to compare the pointers you indicate me, even it could be a 
little difficult for me.

Maybe i will try a 2.6.38, will wait a response from the kvm team.

Regards.

-- 
Jean-Philippe Menil - Pôle réseau Service IRTS
DSI Université de Nantes
jean-philippe.menil@...v-nantes.fr
Tel : 02.53.48.49.27 - Fax : 02.53.48.49.09

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