Re: WARNING in kvm_arch_vcpu_ioctl_run (2)

[Dmitry Vyukov]

On Wed, Nov 1, 2017 at 11:05 PM, syzbot
<bot+d9fbc5c299aa8a95ac07572b4f6e191c0f4efff6@xxxxxxxxxxxxxxxxxxxxxxxxx>
wrote:
> Hello,
>
> syzkaller hit the following crash on
> 045c5205823fc3cd4e5cafdedb2cc7d434424909
> 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.
> C reproducer is attached
> syzkaller reproducer is attached. See https://goo.gl/kgGztJ
> for information about syzkaller reproducers

This happens on more recent commits as well, including e.g. upstream
5f479447d983111c039f1d6d958553c1ad1b2ff1(Oct 30):

------------[ cut here ]------------
WARNING: CPU: 0 PID: 6790 at arch/x86/kvm/x86.c:7265
kvm_arch_vcpu_ioctl_run+0x213/0x5c70 arch/x86/kvm/x86.c:7265
Kernel panic - not syncing: panic_on_warn set ...

CPU: 0 PID: 6790 Comm: syz-executor4 Not tainted 4.14.0-rc7+ #155
Hardware name: Google Google Compute Engine/Google Compute Engine,
BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:16 [inline]
 dump_stack+0x194/0x257 lib/dump_stack.c:52
 panic+0x1e4/0x417 kernel/panic.c:181
 __warn+0x1c4/0x1d9 kernel/panic.c:542
 report_bug+0x211/0x2d0 lib/bug.c:183
 fixup_bug+0x40/0x90 arch/x86/kernel/traps.c:178
 do_trap_no_signal arch/x86/kernel/traps.c:212 [inline]
 do_trap+0x260/0x390 arch/x86/kernel/traps.c:261
 do_error_trap+0x120/0x390 arch/x86/kernel/traps.c:298
 do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:311
 invalid_op+0x18/0x20 arch/x86/entry/entry_64.S:905
RIP: 0010:kvm_arch_vcpu_ioctl_run+0x213/0x5c70 arch/x86/kvm/x86.c:7265
RSP: 0018:ffff8801c5307670 EFLAGS: 00010212
RAX: 0000000000010000 RBX: ffff8801d2da1000 RCX: ffffc9000244f000
RDX: 000000000000003e RSI: ffffffff810e0713 RDI: ffff8801c6da1160
RBP: ffff8801c5307a40 R08: 1ffff10038db4abb R09: 0000000000000001
R10: 0000000000000000 R11: 0000000000000004 R12: 0000000000000000
R13: ffff8801c18d4700 R14: ffff8801c26f1300 R15: ffff8801c6da0f40
 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:00007f61c0ff0be8 EFLAGS: 00000212 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00000000007580d8 RCX: 0000000000452869
RDX: 0000000000000000 RSI: 000000000000ae80 RDI: 0000000000000017
RBP: 0000000000000082 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000212 R12: 00000000006f1580
R13: 00000000ffffffff R14: 00007f61c0ff16d4 R15: 0000000000000001
Dumping ftrace buffer:
   (ftrace buffer empty)
Kernel Offset: disabled
Rebooting in 86400 seconds..



> EPT pointer = 0x00000001cbc2801e
> ------------[ cut here ]------------
> WARNING: CPU: 0 PID: 3247 at arch/x86/kvm/x86.c:7265
> kvm_arch_vcpu_ioctl_run+0x213/0x5c70 arch/x86/kvm/x86.c:7265
> Kernel panic - not syncing: panic_on_warn set ...
>
> CPU: 0 PID: 3247 Comm: syzkaller201086 Not tainted 4.14.0-rc2-next-20170927+
> #30
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
> Google 01/01/2011
> Call Trace:
>  __dump_stack lib/dump_stack.c:16 [inline]
>  dump_stack+0x194/0x257 lib/dump_stack.c:52
>  panic+0x1e4/0x417 kernel/panic.c:181
>  __warn+0x1c4/0x1d9 kernel/panic.c:542
>  report_bug+0x211/0x2d0 lib/bug.c:183
>  fixup_bug+0x40/0x90 arch/x86/kernel/traps.c:178
>  do_trap_no_signal arch/x86/kernel/traps.c:212 [inline]
>  do_trap+0x260/0x390 arch/x86/kernel/traps.c:261
>  do_error_trap+0x120/0x390 arch/x86/kernel/traps.c:298
>  do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:311
>  invalid_op+0x18/0x20 arch/x86/entry/entry_64.S:905
> RIP: 0010:kvm_arch_vcpu_ioctl_run+0x213/0x5c70 arch/x86/kvm/x86.c:7265
> RSP: 0018:ffff8801cb807670 EFLAGS: 00010297
> RAX: ffff8801cbf28280 RBX: ffff8801cbef1000 RCX: ffff8801cd678adc
> RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff8801cd6788f8
> RBP: ffff8801cb807a40 R08: 0000000000000000 R09: 0000000000000001
> R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
> R13: 1ffff10039700f72 R14: ffff8801d6928c00 R15: ffff8801cd6786c0
>  kvm_vcpu_ioctl+0x64c/0x1010 arch/x86/kvm/../../../virt/kvm/kvm_main.c:2551
>  vfs_ioctl fs/ioctl.c:45 [inline]
>  do_vfs_ioctl+0x1b1/0x1530 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: 0033:0x446039
> RSP: 002b:00007f520767adc8 EFLAGS: 00000202 ORIG_RAX: 0000000000000010
> RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000446039
> RDX: 0000000000000000 RSI: 000000000000ae80 RDI: 000000000000000f
> RBP: 0000000000000086 R08: 00007f520767b700 R09: 00007f520767b700
> R10: 00007f520767b700 R11: 0000000000000202 R12: 0000000000000000
> R13: 00007ffdb6946c2f R14: 00007f520767b9c0 R15: 0000000000000000
> 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.
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