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Date:   Wed, 11 Sep 2019 13:38:08 -0700
From:   syzbot <>
Subject: WARNING in handle_desc


syzbot found the following crash on:

HEAD commit:    6d028043 Add linux-next specific files for 20190830
git tree:       linux-next
console output:
kernel config:
dashboard link:
compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
syz repro:
C reproducer:

The bug was bisected to:

commit 0367f205a3b7c0efe774634eef1f4697c79a4132
Author: Paolo Bonzini <>
Date:   Tue Jul 12 08:44:55 2016 +0000

     KVM: vmx: add support for emulating UMIP

bisection log:
final crash:
console output:

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Fixes: 0367f205a3b7 ("KVM: vmx: add support for emulating UMIP")

L1TF CPU bug present and SMT on, data leak possible. See CVE-2018-3646 and for  
------------[ cut here ]------------
WARNING: CPU: 0 PID: 8759 at arch/x86/kvm/vmx/vmx.c:4688  
handle_desc+0x78/0x90 arch/x86/kvm/vmx/vmx.c:4688
Kernel panic - not syncing: panic_on_warn set ...
CPU: 0 PID: 8759 Comm: syz-executor328 Not tainted 5.3.0-rc6-next-20190830  
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS  
Google 01/01/2011
Call Trace:
  __dump_stack lib/dump_stack.c:77 [inline]
  dump_stack+0x172/0x1f0 lib/dump_stack.c:113
  panic+0x2dc/0x755 kernel/panic.c:220
  __warn.cold+0x2f/0x3c kernel/panic.c:581
  report_bug+0x289/0x300 lib/bug.c:195
  fixup_bug arch/x86/kernel/traps.c:179 [inline]
  fixup_bug arch/x86/kernel/traps.c:174 [inline]
  do_error_trap+0x11b/0x200 arch/x86/kernel/traps.c:272
  do_invalid_op+0x37/0x50 arch/x86/kernel/traps.c:291
  invalid_op+0x23/0x30 arch/x86/entry/entry_64.S:1028
RIP: 0010:handle_desc+0x78/0x90 arch/x86/kvm/vmx/vmx.c:4688
Code: 59 00 31 f6 4c 89 e7 e8 26 d5 f4 ff 31 ff 41 89 c4 89 c6 e8 ca 16 59  
00 31 c0 45 85 e4 5b 0f 94 c0 41 5c 5d c3 e8 38 15 59 00 <0f> 0b eb cf e8  
1f f6 93 00 eb ab 0f 1f 00 66 2e 0f 1f 84 00 00 00
RSP: 0018:ffff8880981c79a0 EFLAGS: 00010293
RAX: ffff88809997e000 RBX: 0000000000000000 RCX: ffffffff811940a6
RDX: 0000000000000000 RSI: ffffffff811940d8 RDI: 0000000000000007
RBP: ffff8880981c79b0 R08: ffff88809997e000 R09: ffffed1015d06aed
R10: ffffed1015d06aec R11: ffff8880ae835763 R12: ffff888097628040
R13: 000000000000002f R14: ffff88809762bc0c R15: ffff888097628070
  vmx_handle_exit+0x299/0x15f0 arch/x86/kvm/vmx/vmx.c:5896
  vcpu_enter_guest+0x1087/0x6200 arch/x86/kvm/x86.c:8105
  vcpu_run arch/x86/kvm/x86.c:8169 [inline]
  kvm_arch_vcpu_ioctl_run+0x424/0x1750 arch/x86/kvm/x86.c:8377
  kvm_vcpu_ioctl+0x4dc/0xf50 arch/x86/kvm/../../../virt/kvm/kvm_main.c:2764
  vfs_ioctl fs/ioctl.c:46 [inline]
  file_ioctl fs/ioctl.c:509 [inline]
  do_vfs_ioctl+0xdb6/0x13e0 fs/ioctl.c:696
  ksys_ioctl+0xab/0xd0 fs/ioctl.c:713
  __do_sys_ioctl fs/ioctl.c:720 [inline]
  __se_sys_ioctl fs/ioctl.c:718 [inline]
  __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:718
  do_syscall_64+0xfa/0x760 arch/x86/entry/common.c:290
RIP: 0033:0x443819
Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 48 89 f8 48 89 f7  
48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff  
ff 0f 83 1b 0c fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007ffd0b551188 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007ffd0b551190 RCX: 0000000000443819
RDX: 0000000000000000 RSI: 000000000000ae80 RDI: 0000000000000006
RBP: 0000000000000000 R08: 00000000004010a0 R09: 00000000004010a0
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000004048c0
R13: 0000000000404950 R14: 0000000000000000 R15: 0000000000000000
Kernel Offset: disabled
Rebooting in 86400 seconds..

This bug is generated by a bot. It may contain errors.
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For information about bisection process see:
syzbot can test patches for this bug, for details see:

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