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Message-ID: <4D6B7BAB.9070907@univ-nantes.fr>
Date: Mon, 28 Feb 2011 11:40:43 +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 28/02/2011 11:11, Michael S. Tsirkin a écrit :
> On Mon, Feb 28, 2011 at 09:56:46AM +0100, Jean-Philippe Menil wrote:
>> 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
>>> --
>>> To unsubscribe from this list: send the line "unsubscribe netdev" in
>>> the body of a message to majordomo@...r.kernel.org
>>> More majordomo info at http://vger.kernel.org/majordomo-info.html
>> Hi,
>>
>> thanks for your response.
>>
>> This is what markup_oops.pl return me:
>> "No matching code found"
> Well, let's try to understand what's there.
>
> Do objdumop -ldS kvm.ko
> look for<kvm_set_irq>
>
> and paste the content from start of that function
> to offset 0x2a and a bit beyond.
>
> You can also upload your kvm.ko somewhere, I'll try to take a look.
>
>
>> 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.
> Hmm you know how to add printk to code and rebuild, right?
>
>> 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
So, here is the result for the objdump against the kvm.ko (the
kvm_set_irq part) :
0000000000006a60 <kvm_set_irq>:
kvm_set_irq():
6a60: 41 57 push %r15
6a62: 41 89 f7 mov %esi,%r15d
6a65: 41 56 push %r14
6a67: 41 55 push %r13
6a69: 41 89 cd mov %ecx,%r13d
6a6c: 41 54 push %r12
6a6e: 49 89 fc mov %rdi,%r12
6a71: 55 push %rbp
6a72: 53 push %rbx
6a73: 89 d3 mov %edx,%ebx
6a75: 48 81 ec 98 00 00 00 sub $0x98,%rsp
6a7c: 8b 15 00 00 00 00 mov 0x0(%rip),%edx #
6a82 <kvm_set_irq+0x22>
6a82: 85 d2 test %edx,%edx
6a84: 0f 85 c4 00 00 00 jne 6b4e <kvm_set_irq+0xee>
6a8a: 49 8b 84 24 58 24 00 mov 0x2458(%r12),%rax
6a91: 00
6a92: 3b 98 28 01 00 00 cmp 0x128(%rax),%ebx
6a98: 73 5e jae 6af8 <kvm_set_irq+0x98>
6a9a: 89 db mov %ebx,%ebx
6a9c: 48 8b 84 d8 30 01 00 mov 0x130(%rax,%rbx,8),%rax
6aa3: 00
6aa4: 48 85 c0 test %rax,%rax
6aa7: 74 4f je 6af8 <kvm_set_irq+0x98>
6aa9: 48 89 e2 mov %rsp,%rdx
6aac: 31 db xor %ebx,%ebx
6aae: 48 8b 08 mov (%rax),%rcx
6ab1: 83 c3 01 add $0x1,%ebx
6ab4: 0f 18 09 prefetcht0 (%rcx)
6ab7: 48 8b 48 e0 mov -0x20(%rax),%rcx
6abb: 48 89 0a mov %rcx,(%rdx)
6abe: 48 8b 48 e8 mov -0x18(%rax),%rcx
6ac2: 48 89 4a 08 mov %rcx,0x8(%rdx)
6ac6: 48 8b 48 f0 mov -0x10(%rax),%rcx
6aca: 48 89 4a 10 mov %rcx,0x10(%rdx)
6ace: 48 8b 48 f8 mov -0x8(%rax),%rcx
6ad2: 48 89 4a 18 mov %rcx,0x18(%rdx)
6ad6: 48 8b 08 mov (%rax),%rcx
6ad9: 48 89 4a 20 mov %rcx,0x20(%rdx)
6add: 48 8b 48 08 mov 0x8(%rax),%rcx
6ae1: 48 89 4a 28 mov %rcx,0x28(%rdx)
6ae5: 48 8b 00 mov (%rax),%rax
6ae8: 48 83 c2 30 add $0x30,%rdx
6aec: 48 85 c0 test %rax,%rax
6aef: 75 bd jne 6aae <kvm_set_irq+0x4e>
6af1: eb 07 jmp 6afa <kvm_set_irq+0x9a>
6af3: 0f 1f 44 00 00 nopl 0x0(%rax,%rax,1)
6af8: 31 db xor %ebx,%ebx
6afa: bd ff ff ff ff mov $0xffffffff,%ebp
6aff: 49 89 e6 mov %rsp,%r14
6b02: 85 db test %ebx,%ebx
6b04: 74 34 je 6b3a <kvm_set_irq+0xda>
6b06: 83 eb 01 sub $0x1,%ebx
6b09: 44 89 e9 mov %r13d,%ecx
6b0c: 44 89 fa mov %r15d,%edx
6b0f: 48 63 c3 movslq %ebx,%rax
6b12: 4c 89 e6 mov %r12,%rsi
6b15: 48 8d 04 40 lea (%rax,%rax,2),%rax
6b19: 48 c1 e0 04 shl $0x4,%rax
6b1d: 49 8d 3c 06 lea (%r14,%rax,1),%rdi
6b21: ff 54 04 08 callq *0x8(%rsp,%rax,1)
6b25: 85 c0 test %eax,%eax
6b27: 78 d9 js 6b02 <kvm_set_irq+0xa2>
6b29: 85 ed test %ebp,%ebp
6b2b: ba 00 00 00 00 mov $0x0,%edx
6b30: 0f 48 ea cmovs %edx,%ebp
6b33: 85 db test %ebx,%ebx
6b35: 8d 2c 28 lea (%rax,%rbp,1),%ebp
6b38: 75 cc jne 6b06 <kvm_set_irq+0xa6>
6b3a: 48 81 c4 98 00 00 00 add $0x98,%rsp
6b41: 89 e8 mov %ebp,%eax
6b43: 5b pop %rbx
6b44: 5d pop %rbp
6b45: 41 5c pop %r12
6b47: 41 5d pop %r13
6b49: 41 5e pop %r14
6b4b: 41 5f pop %r15
6b4d: c3 retq
6b4e: 48 8b 2d 00 00 00 00 mov 0x0(%rip),%rbp #
6b55 <kvm_set_irq+0xf5>
6b55: 48 85 ed test %rbp,%rbp
6b58: 0f 84 2c ff ff ff je 6a8a <kvm_set_irq+0x2a>
6b5e: 48 8b 45 00 mov 0x0(%rbp),%rax
6b62: 48 8b 7d 08 mov 0x8(%rbp),%rdi
6b66: 48 83 c5 10 add $0x10,%rbp
6b6a: 44 89 f9 mov %r15d,%ecx
6b6d: 44 89 ea mov %r13d,%edx
6b70: 89 de mov %ebx,%esi
6b72: ff d0 callq *%rax
6b74: 48 8b 45 00 mov 0x0(%rbp),%rax
6b78: 48 85 c0 test %rax,%rax
6b7b: 75 e5 jne 6b62 <kvm_set_irq+0x102>
6b7d: e9 08 ff ff ff jmpq 6a8a <kvm_set_irq+0x2a>
6b82: 66 66 66 66 66 2e 0f nopw %cs:0x0(%rax,%rax,1)
6b89: 1f 84 00 00 00 00 00
I admit that this analysis is too complicated for me.
I, effectively, can rebuild a kernel with more printk, and program a reboot.
The kvm.ko is available through the following address:
http://filex.univ-nantes.fr/get?k=k1jKhQghdcHLz12Z50H
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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