Re: kernel BUG at arch/x86/kvm/x86.c:LINE!

[Dmitry Vyukov]

On Fri, Oct 27, 2017 at 10:48 AM, Wanpeng Li <kernellwp@xxxxxxxxx> wrote:
> Hi Dmitry,
> 2017-10-27 16:34 GMT+08:00 Dmitry Vyukov <dvyukov@xxxxxxxxxx>:
>> On Fri, Oct 27, 2017 at 10:34 AM, syzbot
>> <bot+4facc37258a582d017ddb43934d4419891f41919@xxxxxxxxxxxxxxxxxxxxxxxxx>
>> wrote:
>>> Hello,
>>>
>>> syzkaller hit the following crash on
>>> bb70832dd42b298d4303fd054bf18a78650ff04a
>>> git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/master
>>> compiler: gcc (GCC) 7.1.1 20170620
>>> .config is attached
>>> Raw console output is attached.
>>>
>>> syzkaller reproducer is attached. See https://goo.gl/kgGztJ
>>> for information about syzkaller reproducers
>>
>
> Coud you post a c program?

Please refer to this section of the referenced document:
https://github.com/google/syzkaller/blob/master/docs/syzbot.md#no-reproducer-at-all

> Regards,
> Wanpeng Li
>
>> Last happened on upstream 4ed590271a65b0fbe3eb1cf828ad5af16603c8ce (Oct 26).
>>
>> device syz5 entered promiscuous mode
>> ------------[ cut here ]------------
>> kernel BUG at arch/x86/kvm/x86.c:7182!
>> invalid opcode: 0000 [#1] SMP KASAN
>> Dumping ftrace buffer:
>>    (ftrace buffer empty)
>> Modules linked in:
>> CPU: 0 PID: 5788 Comm: syz-executor3 Not tainted 4.14.0-rc6+ #148
>> Hardware name: Google Google Compute Engine/Google Compute Engine,
>> BIOS Google 01/01/2011
>> task: ffff8801cdc002c0 task.stack: ffff8801974d8000
>> RIP: 0010:complete_emulated_mmio+0x5c2/0x6f0 arch/x86/kvm/x86.c:7182
>> RSP: 0000:ffff8801974df620 EFLAGS: 00010216
>> RAX: 0000000000010000 RBX: ffff8801d2948ac0 RCX: ffffc9000204f000
>> RDX: 000000000000009b RSI: ffffffff810d5db2 RDI: ffff8801d2948ce0
>> RBP: ffff8801974df660 R08: 0000000000000000 R09: ffffed0032e9bf2c
>> R10: 0000000000000000 R11: 0000000000000000 R12: ffffffff810d57f0
>> R13: ffff8801d87fc000 R14: ffff8801d073d780 R15: ffff8801d2948ac0
>> FS:  00007fb474244700(0000) GS:ffff8801db200000(0000) knlGS:0000000000000000
>> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>> CR2: 000000c438c9b000 CR3: 00000001dad6b000 CR4: 00000000001426f0
>> DR0: 0000000020000000 DR1: 0000000000000000 DR2: 0000000000000000
>> DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
>> Call Trace:
>>  kvm_arch_vcpu_ioctl_run+0x2e07/0x5c70 arch/x86/kvm/x86.c:7261
>>  kvm_vcpu_ioctl+0x64c/0x1010 arch/x86/kvm/../../../virt/kvm/kvm_main.c:2551
>>  vfs_ioctl fs/ioctl.c:45 [inline]
>>  do_vfs_ioctl+0x1b1/0x1520 fs/ioctl.c:685
>>  SYSC_ioctl fs/ioctl.c:700 [inline]
>>  SyS_ioctl+0x8f/0xc0 fs/ioctl.c:691
>>  entry_SYSCALL_64_fastpath+0x1f/0xbe
>> RIP: 0033:0x452869
>> RSP: 002b:00007fb474243be8 EFLAGS: 00000212 ORIG_RAX: 0000000000000010
>> RAX: ffffffffffffffda RBX: 0000000000758190 RCX: 0000000000452869
>> RDX: 0000000000000000 RSI: 000000000000ae80 RDI: 0000000000000015
>> RBP: 0000000000000082 R08: 0000000000000000 R09: 0000000000000000
>> R10: 0000000000000000 R11: 0000000000000212 R12: 0000000000000000
>> R13: 0000000000a6f7ff R14: 00007fb4742449c0 R15: 0000000000000002
>> Code: 01 00 00 00 48 89 df e8 ad 9c 47 00 44 89 e6 4c 89 f7 45 31 e4
>> e8 2f 42 4d 00 45 85 ed 41 0f 94 c4 e9 5f fc ff ff e8 8e 63 60 00 <0f>
>> 0b e8 07 29 95 00 e9 9c fa ff ff 89 45 c8 e8 fa 28 95 00 8b
>> RIP: complete_emulated_mmio+0x5c2/0x6f0 arch/x86/kvm/x86.c:7182 RSP:
>> ffff8801974df620
>> ---[ end trace f3b46bcb7f943cb5 ]---
>> Kernel panic - not syncing: Fatal exception
>> Dumping ftrace buffer:
>>    (ftrace buffer empty)
>> Kernel Offset: disabled
>>
>>
>>
>>> kernel BUG at arch/x86/kvm/x86.c:7150!
>>> invalid opcode: 0000 [#1] SMP KASAN
>>> Dumping ftrace buffer:
>>>    (ftrace buffer empty)
>>> Modules linked in:
>>> CPU: 3 PID: 3029 Comm: syz-executor0 Not tainted 4.13.0-rc5-next-20170817+
>>> #5
>>> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
>>> task: ffff88006c488700 task.stack: ffff880067800000
>>> RIP: 0010:complete_emulated_mmio+0x5be/0x6f0 arch/x86/kvm/x86.c:7150
>>> RSP: 0018:ffff880067807620 EFLAGS: 00010297
>>> RAX: ffff88006c488700 RBX: ffff880039428040 RCX: ffff88003942845c
>>> RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff880039428260
>>> RBP: ffff880067807660 R08: 0000000000000000 R09: ffffed000cf00f2c
>>> R10: ffff880067807a58 R11: ffff8800678079d0 R12: ffffffff810d0840
>>> R13: ffff880039c71000 R14: ffff88006da89f00 R15: ffff880039428040
>>> FS:  00007f8311e83700(0000) GS:ffff88006df00000(0000) knlGS:0000000000000000
>>> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>>> CR2: 00007f04f6102000 CR3: 000000003d5de000 CR4: 00000000000026e0
>>> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
>>> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
>>> Call Trace:
>>>  kvm_arch_vcpu_ioctl_run+0x2e2b/0x58b0 arch/x86/kvm/x86.c:7220
>>>  kvm_vcpu_ioctl+0x64c/0x1010 arch/x86/kvm/../../../virt/kvm/kvm_main.c:2591
>>>  vfs_ioctl fs/ioctl.c:45 [inline]
>>>  do_vfs_ioctl+0x1b1/0x1520 fs/ioctl.c:685
>>>  SYSC_ioctl fs/ioctl.c:700 [inline]
>>>  SyS_ioctl+0x8f/0xc0 fs/ioctl.c:691
>>>  entry_SYSCALL_64_fastpath+0x1f/0xbe
>>> RIP: 0033:0x446749
>>> RSP: 002b:00007f8311e82c08 EFLAGS: 00000282 ORIG_RAX: 0000000000000010
>>> RAX: ffffffffffffffda RBX: 0000000000000005 RCX: 0000000000446749
>>> RDX: 0000000000000000 RSI: 000000000000ae80 RDI: 0000000000000005
>>> RBP: 0000000000a5f870 R08: 0000000000000000 R09: 0000000000000000
>>> R10: 0000000000000000 R11: 0000000000000282 R12: 0000000000000000
>>> R13: 0000000000000000 R14: 00007f8311e839c0 R15: 00007f8311e83700
>>> Code: 01 00 00 00 48 89 df e8 51 9e 47 00 44 89 e6 4c 89 f7 45 31 e4 e8 93
>>> 25 4d 00 45 85 ed 41 0f 94 c4 e9 c5 fc ff ff e8 f2 2e 60 00 <0f> 0b e8 1b 99
>>> 94 00 e9 a0 fa ff ff 89 45 c8 e8 0e 99 94 00 8b
>>> RIP: complete_emulated_mmio+0x5be/0x6f0 arch/x86/kvm/x86.c:7150 RSP:
>>> ffff880067807620
>>> ---[ end trace f2b488a12d890bf5 ]---
>>> Kernel panic - not syncing: Fatal exception
>>> Dumping ftrace buffer:
>>>    (ftrace buffer empty)
>>> Kernel Offset: disabled
>>> Rebooting in 86400 seconds..
>>>
>>>
>>> ---
>>> This bug is generated by a dumb bot. It may contain errors.
>>> See https://goo.gl/tpsmEJ for details.
>>> Direct all questions to syzkaller@xxxxxxxxxxxxxxxxx
>>>
>>> syzbot will keep track of this bug report.
>>> Once a fix for this bug is committed, please reply to this email with:
>>> #syz fix: exact-commit-title
>>> To mark this as a duplicate of another syzbot report, please reply with:
>>> #syz dup: exact-subject-of-another-report
>>> If it's a one-off invalid bug report, please reply with:
>>> #syz invalid
>>> Note: if the crash happens again, it will cause creation of a new bug
>>> report.
>>>
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