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Message-ID: <4D70AF3B.5080007@univ-nantes.fr>
Date: Fri, 04 Mar 2011 10:22:03 +0100
From: Jean-Philippe Menil <jean-philippe.menil@...v-nantes.fr>
To: "Michael S. Tsirkin" <mst@...hat.com>
CC: netdev@...r.kernel.org, kvm@...r.kernel.org,
virtualization@...ts.linux-foundation.org
Subject: Re: Bug inkvm_set_irq
Le 03/03/2011 16:55, Michael S. Tsirkin a écrit :
> On Thu, Mar 03, 2011 at 04:26:11PM +0100, Jean-Philippe Menil wrote:
>> Le 03/03/2011 15:47, Michael S. Tsirkin a écrit :
>>> On Tue, Mar 01, 2011 at 03:39:12PM +0100, Jean-Philippe Menil wrote:
>>>> so this time the bug is:
>>>>
>>>> [17882.612303] BUG: unable to handle kernel paging request at
>>>> 0000000000002458
>>>> [17882.612342] IP: [<ffffffffa03898a0>] kvm_set_irq+0x30/0x140 [kvm]
>>>>
>>>> markup_oops give me this:
>>>>
>>>> root@...shire:~# cat bug-0103.txt | perl markup_oops.pl -m
>>>> /lib/modules/2.6.37.2-dsiun-110105+/kernel/arch/x86/kvm/kvm.ko
>>>> /boot/vmlinuz-2.6.37.2-dsiun-110105+
>>>> vmaoffset = 18446744072102621184 ffffffffa0389871: 48 89 e5 mov
>>>> %rsp,%rbp
>>>> ffffffffa0389874: 41 57 push %r15
>>>> ffffffffa0389876: 41 89 cf mov %ecx,%r15d | %r15
>>>> => 1 %ecx = 1
>>>> ffffffffa0389879: 41 56 push %r14 | %r14
>>>> => ffffffffa038aad0
>>>> ffffffffa038987b: 41 55 push %r13
>>>> ffffffffa038987d: 49 89 fd mov %rdi,%r13 | %edi
>>>> = 0 %r13 => 0
>>>> ffffffffa0389880: 41 54 push %r12 | %r12 => 0
>>>> ffffffffa0389882: 53 push %rbx
>>>> ffffffffa0389883: 89 d3 mov %edx,%ebx | %ebx => 1a
>>>> ffffffffa0389885: 48 81 ec a8 00 00 00 sub $0xa8,%rsp
>>>> ffffffffa038988c: 8b 15 00 00 00 00 mov 0x0(%rip),%edx
>>>> # ffffffffa0389892<kvm_set_irq+0x22>
>>>> ffffffffa0389892: 89 b5 3c ff ff ff mov %esi,-0xc4(%rbp) |
>>>> %esi = 0
>>>> ffffffffa0389898: 85 d2 test %edx,%edx | %edx => 0
>>>> ffffffffa038989a: 0f 85 d5 00 00 00 jne ffffffffa0389975
>>>> <kvm_set_irq+0x105>
>>>> *ffffffffa03898a0: 49 8b 85 58 24 00 00 mov 0x2458(%r13),%rax |
>>>> %eax = 0 %r13 = 0<--- faulting instruction
>>>> ffffffffa03898a7: 3b 98 28 01 00 00 cmp 0x128(%rax),%ebx
>>>> ffffffffa03898ad: 73 61 jae ffffffffa0389910
>>>> <kvm_set_irq+0xa0>
>>>> ffffffffa03898af: 89 db mov %ebx,%ebx
>>>> ffffffffa03898b1: 48 8b 84 d8 30 01 00 mov 0x130(%rax,%rbx,8),%rax
>>>> ffffffffa03898b8: 00
>>>> ffffffffa03898b9: 48 85 c0 test %rax,%rax
>>>> ffffffffa03898bc: 74 52 je ffffffffa0389910
>>>> <kvm_set_irq+0xa0>
>>>> ffffffffa03898be: 48 8d 95 40 ff ff ff lea -0xc0(%rbp),%rdx
>>>> ffffffffa03898c5: 31 db xor %ebx,%ebx
>>>> ffffffffa03898c7: 48 8b 08 mov (%rax),%rcx
>>>> ffffffffa03898ca: 83 c3 01 add $0x1,%ebx
>>>> ffffffffa03898cd: 0f 18 09 prefetcht0 (%rcx)
>>>> ffffffffa03898d0: 48 8b 48 e0 mov -0x20(%rax),%rcx
>>>> ffffffffa03898d4: 48 89 0a mov %rcx,(%rdx)
>>>> ffffffffa03898d7: 48 8b 48 e8 mov -0x18(%rax),%rcx
>>>> ffffffffa03898db: 48 89 4a 08 mov %rcx,0x8(%rdx)
>>>> ffffffffa03898df: 48 8b 48 f0 mov -0x10(%rax),%rcx
>>>> ffffffffa03898e3: 48 89 4a 10 mov %rcx,0x10(%rdx)
>>>> ffffffffa03898e7: 48 8b 48 f8 mov -0x8(%rax),%rcx
>>>> ffffffffa03898eb: 48 89 4a 18 mov %rcx,0x18(%rdx)
>>>>
>>>> wich correspond to offset 68a0 (from objdump):
>>>>
>>>> kvm_set_irq():
>>>> /usr/src/GIT/linux-2.6-stable/arch/x86/kvm/../../../virt/kvm/irq_comm.c:161
>>>> 68a0: 49 8b 85 58 24 00 00 mov 0x2458(%r13),%rax
>>>> /usr/src/GIT/linux-2.6-stable/arch/x86/kvm/../../../virt/kvm/irq_comm.c:162
>>>> 68a7: 3b 98 28 01 00 00 cmp 0x128(%rax),%ebx
>>>>
>>>> root@...shire:~# addr2line -e
>>>> /lib/modules/2.6.37.2-dsiun-110105+/kernel/arch/x86/kvm/kvm.ko
>>>> 0x68a0
>>>> /usr/src/GIT/linux-2.6-stable/arch/x86/kvm/../../../virt/kvm/irq_comm.c:161
>>>>
>>>> So here kvm->irq_routing is null.
>>>>
>>>> How can it be?
>>>>
>>>> Regards.
>>> Not null, this seems to be invalid.
>>> I suspect use after free where the kvm pointer is
>>> pointing at some random memory. Use after free?
>>> Could you please try enabling a slab debugger,
>>> recompile and rerun the test?
>>>
>> Hi,
>>
>> I'm not sure to activate the right thing.
>> Is that what you want?
>>
>> CONFIG_SLAB=y
>> CONFIG_SLABINFO=y
>> CONFIG_DEBUG_SLAB=y
>> CONFIG_DEBUG_SLAB_LEAK=y
>>
>> Regards.
> Yes, maybe disable SLAB_LEAK.
>
>> --
>> 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
> --
> To unsubscribe from this list: send the line "unsubscribe kvm" in
> the body of a message to majordomo@...r.kernel.org
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Hi,
so this time, here is what markup_oops says:
root@...shire:~# cat oops-0403.txt | perl markup_oops.pl -m
/lib/modules/2.6.37.2.999-dsiun-110105+/kernel/arch/x86/kvm/kvm.ko
/boot/vmlinuz-2.6.37.2.999-dsiun-110105+
vmaoffset = 18446744072102948864 ffffffffa03d9811: 48 89
e5 mov %rsp,%rbp
ffffffffa03d9814: 41 57 push %r15
ffffffffa03d9816: 41 89 cf mov %ecx,%r15d |
%r15 => 1 %ecx = 1
ffffffffa03d9819: 41 56 push %r14 |
%r14 => ffffffffa03daa50
ffffffffa03d981b: 41 55 push %r13
ffffffffa03d981d: 49 89 fd mov %rdi,%r13 |
%edi = 6b6b6b6b6b6b6b6b %r13 => 6b6b6b6b6b6b6b6b
ffffffffa03d9820: 41 54 push %r12 |
%r12 => 6b6b6b6b6b6b6b6b
ffffffffa03d9822: 53 push %rbx
ffffffffa03d9823: 89 d3 mov %edx,%ebx |
%ebx => 6b6b6b6b
ffffffffa03d9825: 48 81 ec a8 00 00 00 sub $0xa8,%rsp
ffffffffa03d982c: 8b 15 00 00 00 00 mov
0x0(%rip),%edx # ffffffffa03d9832 <kvm_set_irq+0x22>
ffffffffa03d9832: 89 b5 3c ff ff ff mov %esi,-0xc4(%rbp)
| %esi = 0
ffffffffa03d9838: 85 d2 test %edx,%edx |
%edx => 0
ffffffffa03d983a: 0f 85 d5 00 00 00 jne ffffffffa03d9915
<kvm_set_irq+0x105>
*ffffffffa03d9840: 49 8b 85 58 24 00 00 mov 0x2458(%r13),%rax
| %eax = 0 %r13 = 6b6b6b6b6b6b6b6b <--- faulting instruction
ffffffffa03d9847: 3b 98 28 01 00 00 cmp 0x128(%rax),%ebx
ffffffffa03d984d: 73 61 jae ffffffffa03d98b0
<kvm_set_irq+0xa0>
ffffffffa03d984f: 89 db mov %ebx,%ebx
ffffffffa03d9851: 48 8b 84 d8 30 01 00 mov
0x130(%rax,%rbx,8),%rax
ffffffffa03d9858: 00
ffffffffa03d9859: 48 85 c0 test %rax,%rax
ffffffffa03d985c: 74 52 je ffffffffa03d98b0
<kvm_set_irq+0xa0>
ffffffffa03d985e: 48 8d 95 40 ff ff ff lea -0xc0(%rbp),%rdx
ffffffffa03d9865: 31 db xor %ebx,%ebx
ffffffffa03d9867: 48 8b 08 mov (%rax),%rcx
ffffffffa03d986a: 83 c3 01 add $0x1,%ebx
ffffffffa03d986d: 0f 18 09 prefetcht0 (%rcx)
ffffffffa03d9870: 48 8b 48 e0 mov -0x20(%rax),%rcx
ffffffffa03d9874: 48 89 0a mov %rcx,(%rdx)
ffffffffa03d9877: 48 8b 48 e8 mov -0x18(%rax),%rcx
ffffffffa03d987b: 48 89 4a 08 mov %rcx,0x8(%rdx)
ffffffffa03d987f: 48 8b 48 f0 mov -0x10(%rax),%rcx
ffffffffa03d9883: 48 89 4a 10 mov %rcx,0x10(%rdx)
ffffffffa03d9887: 48 8b 48 f8 mov -0x8(%rax),%rcx
ffffffffa03d988b: 48 89 4a 18 mov %rcx,0x18(%rdx)
Is that you wanted, the "6b6b6b6b6b6b6b6b" ?
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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