kernel BUG in kvm_hv_set_msr_common

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: a89b48fe9308 Linux 4.19.199
git tree: linux-4.19.y
console output: https://syzkaller.appspot.com/x/log.txt?x=169ea392300000
kernel config: https://syzkaller.appspot.com/x/.config?x=72b91bfdb2e2b668
dashboard link: https://syzkaller.appspot.com/bug?extid=df6655ee4555163e7df7
compiler: gcc version 10.2.1 20210110 (Debian 10.2.1-6)

Unfortunately, I don't have any reproducer for this issue yet.

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+df6655...@syzkaller.appspotmail.com

------------[ cut here ]------------
kernel BUG at include/linux/kvm_host.h:560!
invalid opcode: 0000 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 19410 Comm: syz-executor.3 Not tainted 4.19.199-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:kvm_vcpu_get_idx include/linux/kvm_host.h:560 [inline]
RIP: 0010:kvm_hv_set_msr arch/x86/kvm/hyperv.c:1070 [inline]
RIP: 0010:kvm_hv_set_msr_common+0x24b2/0x2b70 arch/x86/kvm/hyperv.c:1285
Code: 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 89 06 00 00 48 8b 44 24 08 45 31 ff 48 89 85 a0 4c 00 00 e9 55 dc ff ff e8 de 16 4b 00 <0f> 0b 48 89 ef e8 a4 e5 80 00 e9 d4 dd ff ff e8 9a e5 80 00 e9 9a
RSP: 0018:ffff8880354ff4d8 EFLAGS: 00010212
RAX: 0000000000040000 RBX: 0000000000000000 RCX: ffffc9000c562000
RDX: 000000000000014d RSI: ffffffff81176b42 RDI: 0000000000000004
RBP: ffff88804c008a40 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000004 R11: 00000000841e52e2 R12: dffffc0000000000
R13: 0000000000000000 R14: ffffed1009801148 R15: ffffc90005c0f9d0
FS: 00007f6ffa088700(0000) GS:ffff8880ba000000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000004e4b40 CR3: 00000000ac361000 CR4: 00000000001426f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
kvm_set_msr_common+0x44a/0x2490 arch/x86/kvm/x86.c:2631
vmx_set_msr+0x759/0x2230 arch/x86/kvm/vmx.c:4317
kvm_set_msr+0x2b3/0x360 arch/x86/kvm/x86.c:1348
do_set_msr+0x94/0xe0 arch/x86/kvm/x86.c:1377
__msr_io arch/x86/kvm/x86.c:2945 [inline]
msr_io+0x17a/0x290 arch/x86/kvm/x86.c:2981
kvm_arch_vcpu_ioctl+0xeb5/0x2d50 arch/x86/kvm/x86.c:3967
kvm_vcpu_ioctl+0x891/0xe10 arch/x86/kvm/../../../virt/kvm/kvm_main.c:2998
vfs_ioctl fs/ioctl.c:46 [inline]
file_ioctl fs/ioctl.c:501 [inline]
do_vfs_ioctl+0xcdb/0x12e0 fs/ioctl.c:688
ksys_ioctl+0x9b/0xc0 fs/ioctl.c:705
__do_sys_ioctl fs/ioctl.c:712 [inline]
__se_sys_ioctl fs/ioctl.c:710 [inline]
__x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:710
do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x4665e9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f6ffa088188 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 000000000056c038 RCX: 00000000004665e9
RDX: 0000000020001a40 RSI: 000000004008ae89 RDI: 0000000000000006
RBP: 00000000004bfcc4 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056c038
R13: 00007ffc3732a8df R14: 00007f6ffa088300 R15: 0000000000022000
Modules linked in:
kvm [19407]: vcpu0, guest rIP: 0xfff0 disabled perfctr wrmsr: 0x186 data 0x3
---[ end trace 2929de5925e0f887 ]---
RIP: 0010:kvm_vcpu_get_idx include/linux/kvm_host.h:560 [inline]
RIP: 0010:kvm_hv_set_msr arch/x86/kvm/hyperv.c:1070 [inline]
RIP: 0010:kvm_hv_set_msr_common+0x24b2/0x2b70 arch/x86/kvm/hyperv.c:1285
Code: 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 89 06 00 00 48 8b 44 24 08 45 31 ff 48 89 85 a0 4c 00 00 e9 55 dc ff ff e8 de 16 4b 00 <0f> 0b 48 89 ef e8 a4 e5 80 00 e9 d4 dd ff ff e8 9a e5 80 00 e9 9a
FAT-fs (loop4): bogus number of reserved sectors
FAT-fs (loop4): Can't find a valid FAT filesystem
RSP: 0018:ffff8880354ff4d8 EFLAGS: 00010212
RAX: 0000000000040000 RBX: 0000000000000000 RCX: ffffc9000c562000
FAT-fs (loop4): bogus number of reserved sectors
FAT-fs (loop4): Can't find a valid FAT filesystem
RDX: 000000000000014d RSI: ffffffff81176b42 RDI: 0000000000000004
RBP: ffff88804c008a40 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000004 R11: 00000000841e52e2 R12: dffffc0000000000
R13: 0000000000000000 R14: ffffed1009801148 R15: ffffc90005c0f9d0
FS: 00007f6ffa088700(0000) GS:ffff8880ba000000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f9ad0802008 CR3: 00000000ac361000 CR4: 00000000001426f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400


---
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[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit: a89b48fe9308 Linux 4.19.199
git tree: linux-4.19.y

console output: https://syzkaller.appspot.com/x/log.txt?x=15b39004300000

kernel config: https://syzkaller.appspot.com/x/.config?x=72b91bfdb2e2b668
dashboard link: https://syzkaller.appspot.com/bug?extid=df6655ee4555163e7df7
compiler: gcc version 10.2.1 20210110 (Debian 10.2.1-6)

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=16358a2a300000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+df6655...@syzkaller.appspotmail.com

------------[ cut here ]------------
kernel BUG at include/linux/kvm_host.h:560!
invalid opcode: 0000 [#1] PREEMPT SMP KASAN

CPU: 1 PID: 13499 Comm: syz-executor.4 Not tainted 4.19.199-syzkaller #0

Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:kvm_vcpu_get_idx include/linux/kvm_host.h:560 [inline]
RIP: 0010:kvm_hv_set_msr arch/x86/kvm/hyperv.c:1070 [inline]
RIP: 0010:kvm_hv_set_msr_common+0x24b2/0x2b70 arch/x86/kvm/hyperv.c:1285
Code: 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 89 06 00 00 48 8b 44 24 08 45 31 ff 48 89 85 a0 4c 00 00 e9 55 dc ff ff e8 de 16 4b 00 <0f> 0b 48 89 ef e8 a4 e5 80 00 e9 d4 dd ff ff e8 9a e5 80 00 e9 9a

RSP: 0018:ffff8880b43f74d8 EFLAGS: 00010293
RAX: ffff8880993d81c0 RBX: 0000000000000000 RCX: ffffffff81174974
RDX: 0000000000000000 RSI: ffffffff81176b42 RDI: 0000000000000004
RBP: ffff8880a3190c80 R08: 0000000000000000 R09: 0000000000000000

R10: 0000000000000004 R11: 00000000841e52e2 R12: dffffc0000000000

R13: 0000000000000000 R14: ffffed1014632190 R15: ffffc9000763b9d0
FS: 00007ff843a25700(0000) GS:ffff8880ba100000(0000) knlGS:0000000000000000

CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033

CR2: 0000000003387708 CR3: 00000000a5481000 CR4: 00000000001426e0

DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
kvm_set_msr_common+0x44a/0x2490 arch/x86/kvm/x86.c:2631
vmx_set_msr+0x759/0x2230 arch/x86/kvm/vmx.c:4317
kvm_set_msr+0x2b3/0x360 arch/x86/kvm/x86.c:1348
do_set_msr+0x94/0xe0 arch/x86/kvm/x86.c:1377
__msr_io arch/x86/kvm/x86.c:2945 [inline]
msr_io+0x17a/0x290 arch/x86/kvm/x86.c:2981
kvm_arch_vcpu_ioctl+0xeb5/0x2d50 arch/x86/kvm/x86.c:3967
kvm_vcpu_ioctl+0x891/0xe10 arch/x86/kvm/../../../virt/kvm/kvm_main.c:2998
vfs_ioctl fs/ioctl.c:46 [inline]
file_ioctl fs/ioctl.c:501 [inline]
do_vfs_ioctl+0xcdb/0x12e0 fs/ioctl.c:688
ksys_ioctl+0x9b/0xc0 fs/ioctl.c:705
__do_sys_ioctl fs/ioctl.c:712 [inline]
__se_sys_ioctl fs/ioctl.c:710 [inline]
__x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:710
do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x4665e9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48

RSP: 002b:00007ff843a25188 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 000000000056c0f0 RCX: 00000000004665e9
RDX: 0000000020001a40 RSI: 000000004008ae89 RDI: 0000000000000005

RBP: 00000000004bfcc4 R08: 0000000000000000 R09: 0000000000000000

R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056c0f0
R13: 00007fffc4df6b5f R14: 00007ff843a25300 R15: 0000000000022000
Modules linked in:
---[ end trace fdb8845278ebe8e8 ]---

RIP: 0010:kvm_vcpu_get_idx include/linux/kvm_host.h:560 [inline]
RIP: 0010:kvm_hv_set_msr arch/x86/kvm/hyperv.c:1070 [inline]
RIP: 0010:kvm_hv_set_msr_common+0x24b2/0x2b70 arch/x86/kvm/hyperv.c:1285
Code: 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 89 06 00 00 48 8b 44 24 08 45 31 ff 48 89 85 a0 4c 00 00 e9 55 dc ff ff e8 de 16 4b 00 <0f> 0b 48 89 ef e8 a4 e5 80 00 e9 d4 dd ff ff e8 9a e5 80 00 e9 9a

RSP: 0018:ffff8880b43f74d8 EFLAGS: 00010293
RAX: ffff8880993d81c0 RBX: 0000000000000000 RCX: ffffffff81174974
RDX: 0000000000000000 RSI: ffffffff81176b42 RDI: 0000000000000004
RBP: ffff8880a3190c80 R08: 0000000000000000 R09: 0000000000000000

R10: 0000000000000004 R11: 00000000841e52e2 R12: dffffc0000000000

R13: 0000000000000000 R14: ffffed1014632190 R15: ffffc9000763b9d0
FS: 00007ff843a25700(0000) GS:ffff8880ba100000(0000) knlGS:0000000000000000

CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033

CR2: 0000000000540198 CR3: 00000000a5481000 CR4: 00000000001426e0

[syzbot]

syzbot suspects this issue was fixed by commit:

commit 41d2efaed5bdabe675857e6ecaa324b5504fc268
Author: Radim Krčmář <rkr...@redhat.com>
Date: Thu Nov 7 12:53:42 2019 +0000

KVM: remember position in kvm->vcpus array

bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=16710450b00000
start commit: a89b48fe9308 Linux 4.19.199
git tree: linux-4.19.y

kernel config: https://syzkaller.appspot.com/x/.config?x=72b91bfdb2e2b668
dashboard link: https://syzkaller.appspot.com/bug?extid=df6655ee4555163e7df7

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=16358a2a300000

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

#syz fix: KVM: remember position in kvm->vcpus array

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