WARNING in handle_desc

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: dbc29aff Linux 4.19.74
git tree: linux-4.19.y
console output: https://syzkaller.appspot.com/x/log.txt?x=16fd953d600000
kernel config: https://syzkaller.appspot.com/x/.config?x=c3b60234a72e3893
dashboard link: https://syzkaller.appspot.com/bug?extid=3e5061d8f00ce2ab75a1
compiler: gcc (GCC) 9.0.0 20181231 (experimental)
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=16953b65600000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1293eb65600000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+3e5061...@syzkaller.appspotmail.com

audit: type=1400 audit(1568974230.200:36): avc: denied { map } for
pid=7617 comm="syz-executor866" path="/root/syz-executor866017908"
dev="sda1" ino=16483 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023
tcontext=unconfined_u:object_r:user_home_t:s0 tclass=file permissive=1
L1TF CPU bug present and SMT on, data leak possible. See CVE-2018-3646 and
https://www.kernel.org/doc/html/latest/admin-guide/hw-vuln/l1tf.html for
details.
------------[ cut here ]------------
WARNING: CPU: 0 PID: 7617 at arch/x86/kvm/vmx.c:7251
handle_desc.cold+0x11/0x18 arch/x86/kvm/vmx.c:7251
Kernel panic - not syncing: panic_on_warn set ...

CPU: 0 PID: 7617 Comm: syz-executor866 Not tainted 4.19.74 #0
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+0x263/0x507 kernel/panic.c:185
__warn.cold+0x20/0x4a kernel/panic.c:540
report_bug+0x263/0x2b0 lib/bug.c:186
fixup_bug arch/x86/kernel/traps.c:178 [inline]
fixup_bug arch/x86/kernel/traps.c:173 [inline]
do_error_trap+0x204/0x360 arch/x86/kernel/traps.c:296
do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:316
invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:1037
RIP: 0010:handle_desc.cold+0x11/0x18 arch/x86/kvm/vmx.c:7251
Code: 00 48 c7 c7 a0 bd 43 87 c6 05 7d 72 20 08 01 e8 a0 17 39 00 e9 2e 8b
fb ff e8 c2 b0 4e 00 48 c7 c7 00 be 43 87 e8 8a 17 39 00 <0f> 0b e9 ce 8f
fb ff e8 aa b0 4e 00 89 de 48 c7 c7 00 bf 43 87 c6
RSP: 0018:ffff888086c87950 EFLAGS: 00010286
RAX: 0000000000000024 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff8155dbd6 RDI: ffffed1010d90f1c
RBP: ffff888086c87960 R08: 0000000000000024 R09: ffffed1015d05079
R10: ffffed1015d05078 R11: ffff8880ae8283c7 R12: ffff8880863b0040
R13: 0000000000000000 R14: ffff8880863b0040 R15: 000000000000002f
vmx_handle_exit+0x276/0x16b0 arch/x86/kvm/vmx.c:10183
vcpu_enter_guest+0x10ca/0x5ed0 arch/x86/kvm/x86.c:7743
vcpu_run arch/x86/kvm/x86.c:7806 [inline]
kvm_arch_vcpu_ioctl_run+0x457/0x16b0 arch/x86/kvm/x86.c:8006
kvm_vcpu_ioctl+0x4dc/0xf90 arch/x86/kvm/../../../virt/kvm/kvm_main.c:2617
vfs_ioctl fs/ioctl.c:46 [inline]
file_ioctl fs/ioctl.c:501 [inline]
do_vfs_ioctl+0xd5f/0x1380 fs/ioctl.c:688
ksys_ioctl+0xab/0xd0 fs/ioctl.c:705
__do_sys_ioctl fs/ioctl.c:712 [inline]
__se_sys_ioctl fs/ioctl.c:710 [inline]
__x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:710
do_syscall_64+0xfd/0x620 arch/x86/entry/common.c:293
entry_SYSCALL_64_after_hwframe+0x49/0xbe
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:00007ffd39ec7a68 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007ffd39ec7a70 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..


---
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[syzbot]

syzbot suspects this bug was fixed by commit:

commit 21874027e1deba5a5b8edaa6de8e49a4a2dd99b3
Author: Wanpeng Li <wanp...@tencent.com>
Date: Wed Sep 18 09:50:10 2019 +0000

KVM: X86: Fix userspace set invalid CR4

bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=17d11edae00000
start commit: dbc29aff Linux 4.19.74
git tree: linux-4.19.y

kernel config: https://syzkaller.appspot.com/x/.config?x=c3b60234a72e3893
dashboard link: https://syzkaller.appspot.com/bug?extid=3e5061d8f00ce2ab75a1

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=16953b65600000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1293eb65600000

If the result looks correct, please mark the bug fixed by replying with:

#syz fix: KVM: X86: Fix userspace set invalid CR4

For information about bisection process see: https://goo.gl/tpsmEJ#bisection