Re: BUG: unable to handle kernel paging request in wait_lapic_expire

[Dmitry Vyukov]

On Sun, Dec 3, 2017 at 3:28 PM, syzbot
<bot+51154054bce9a47d13fe39992500c94154513813@xxxxxxxxxxxxxxxxxxxxxxxxx>
wrote:
> Hello,
>
> syzkaller hit the following crash on
> d127129e85a020879f334154300ddd3f7ec21c1e
> 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.
>
> Unfortunately, I don't have any reproducer for this bug yet.
>
>
> BUG: unable to handle kernel paging request at fffffffffffffff8
> IP: wait_lapic_expire+0x98/0x7f0 arch/x86/kvm/lapic.c:1396
> PGD 5e28067 P4D 5e28067 PUD 5e2a067 PMD 0
> Oops: 0002 [#1] SMP KASAN
> Dumping ftrace buffer:
>    (ftrace buffer empty)
> Modules linked in:
> CPU: 0 PID: 4463 Comm: syz-executor4 Not tainted 4.15.0-rc1-next-20171129+
> #55
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
> Google 01/01/2011
> task: ffff8801cde40380 task.stack: ffff8801ced38000
> RIP: 0010:wait_lapic_expire+0x98/0x7f0 arch/x86/kvm/lapic.c:1396
> RSP: 0018:ffff8801ced3f5c0 EFLAGS: 00010046
> RAX: 1ffff1003a0ce0f4 RBX: 1ffff10039da7ebb RCX: ffffffff81167488
> RDX: 000000000000284c RSI: ffffc900030e0000 RDI: ffff8801d06707a0
> RBP: ffff8801ced3f6a0 R08: ffff88018f4adf58 R09: 1ffff10039da7eaf
> R10: ffff8801cde40380 R11: 0000000000000001 R12: ffff8801d06b12c0
> R13: ffff8801d06703c0 R14: ffff8801d06703f0 R15: ffff8801d06703c0
> FS:  00007f4acd2f5700(0000) GS:ffff8801db400000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: fffffffffffffff8 CR3: 00000001d1531000 CR4: 00000000001426f0
> Call Trace:
>  vcpu_enter_guest arch/x86/kvm/x86.c:7011 [inline]
>  vcpu_run arch/x86/kvm/x86.c:7146 [inline]
>  kvm_arch_vcpu_ioctl_run+0x182c/0x5c60 arch/x86/kvm/x86.c:7314
>  kvm_vcpu_ioctl+0x64c/0x1010 arch/x86/kvm/../../../virt/kvm/kvm_main.c:2574
>  vfs_ioctl fs/ioctl.c:46 [inline]
>  do_vfs_ioctl+0x1b1/0x1530 fs/ioctl.c:686
>  SYSC_ioctl fs/ioctl.c:701 [inline]
>  SyS_ioctl+0x8f/0xc0 fs/ioctl.c:692
>  entry_SYSCALL_64_fastpath+0x1f/0x96
> RIP: 0033:0x4529d9
> RSP: 002b:00007f4acd2f4c58 EFLAGS: 00000212 ORIG_RAX: 0000000000000010
> RAX: ffffffffffffffda RBX: 00000000007580d8 RCX: 00000000004529d9
> RDX: 0000000000000000 RSI: 000000000000ae80 RDI: 000000000000001a
> RBP: 0000000000000214 R08: 0000000000000000 R09: 0000000000000000
> R10: 0000000000000000 R11: 0000000000000212 R12: 00000000006f0280
> R13: 00000000ffffffff R14: 00007f4acd2f56d4 R15: 0000000000000021
> Code: 40 10 f3 f3 f3 f3 e8 88 c6 59 00 49 8d bd e0 03 00 00 48 89 f8 48 c1
> e8 03 42 80 3c 20 00 0f 85 f2 06 00 00 4d 8b a5 e0 03 00 00 <cc> 1f 44 00 00
> e8 5e c6 59 00 4d 8d 7c 24 70 e8 54 c6 59 00 4c
> RIP: wait_lapic_expire+0x98/0x7f0 arch/x86/kvm/lapic.c:1396 RSP:
> ffff8801ced3f5c0
> CR2: fffffffffffffff8
> ---[ end trace ce0f60eca9bd2476 ]---
> Kernel panic - not syncing: Fatal exception
> Dumping ftrace buffer:
>    (ftrace buffer empty)
> Kernel Offset: disabled
> Rebooting in 86400 seconds..

#syz dup: BUG: unable to handle kernel paging request in __switch_to

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