kernel BUG in vhost_get_vq_desc

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: a35d65bedfbc Linux 4.14.267
git tree: linux-4.14.y
console output: https://syzkaller.appspot.com/x/log.txt?x=15f6f0da700000
kernel config: https://syzkaller.appspot.com/x/.config?x=8535d773e783c59a
dashboard link: https://syzkaller.appspot.com/bug?extid=a6f003681ffcde48726c
compiler: gcc version 10.2.1 20210110 (Debian 10.2.1-6)
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=165447e8700000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1575a0b2700000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+a6f003...@syzkaller.appspotmail.com

------------[ cut here ]------------
kernel BUG at drivers/vhost/vhost.c:2240!
invalid opcode: 0000 [#1] PREEMPT SMP KASAN
Modules linked in:
CPU: 0 PID: 7970 Comm: vhost-7969 Not tainted 4.14.267-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff88808f8be6c0 task.stack: ffff8880b3b68000
RIP: 0010:vhost_get_vq_desc+0x1b5c/0x20c0 drivers/vhost/vhost.c:2240
RSP: 0018:ffff8880b3b6fb80 EFLAGS: 00010297
RAX: ffff88808f8be6c0 RBX: 0000000000000001 RCX: dffffc0000000000
RDX: 0000000000000000 RSI: ffff8880b3b6fdb8 RDI: ffff888091784b86
RBP: 0000000000000000 R08: 0000000000000400 R09: 0000000000000001
R10: ffff8880b3b6fc5f R11: ffff88808f8be6c0 R12: ffff888091784b98
R13: 0000000000000000 R14: 0000000000000000 R15: ffff8880917849c8
FS: 0000000000000000(0000) GS:ffff8880ba400000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000002 CR3: 00000000ab171000 CR4: 00000000003406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
vhost_vsock_handle_tx_kick+0x1d1/0x900 drivers/vhost/vsock.c:460
vhost_worker+0x267/0x450 drivers/vhost/vhost.c:364
kthread+0x30d/0x420 kernel/kthread.c:232
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404
Code: 94 00 00 00 48 c7 c6 c0 86 48 88 48 c7 c7 38 08 06 8a 48 89 ca 48 c1 e1 04 48 01 d9 e8 ee 38 aa fd e9 c1 fc ff ff e8 44 2e d6 fb <0f> 0b e8 3d 2e d6 fb 44 89 f2 b9 10 00 00 00 48 c7 c6 c0 84 48
RIP: vhost_get_vq_desc+0x1b5c/0x20c0 drivers/vhost/vhost.c:2240 RSP: ffff8880b3b6fb80
---[ end trace 6d65af052c41cb5b ]---


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