general protection fault in vhost_net_chr_write_iter

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: a74d0e93 Linux 4.14.126
git tree: linux-4.14.y
console output: https://syzkaller.appspot.com/x/log.txt?x=14d04476a00000
kernel config: https://syzkaller.appspot.com/x/.config?x=cb5b89703401900e
dashboard link: https://syzkaller.appspot.com/bug?extid=faa36146ac3eb8bc9af1
compiler: gcc (GCC) 9.0.0 20181231 (experimental)

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

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+faa361...@syzkaller.appspotmail.com

sock_ioctl+0x2a6/0x470 net/socket.c:1071
vfs_ioctl fs/ioctl.c:46 [inline]
file_ioctl fs/ioctl.c:500 [inline]
do_vfs_ioctl+0x7ae/0x1060 fs/ioctl.c:684
kasan: GPF could be caused by NULL-ptr deref or user memory access
SYSC_ioctl fs/ioctl.c:701 [inline]
SyS_ioctl+0x8f/0xc0 fs/ioctl.c:692
general protection fault: 0000 [#1] PREEMPT SMP KASAN
Modules linked in:
do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292
CPU: 0 PID: 9151 Comm: syz-executor.2 Not tainted 4.14.126 #20
entry_SYSCALL_64_after_hwframe+0x42/0xb7
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
RIP: 0033:0x4592c9
task: ffff88805785e300 task.stack: ffff888057698000
RSP: 002b:00007f0742e47c78 EFLAGS: 00000246
RIP: 0010:vhost_del_umem_range drivers/vhost/vhost.c:953 [inline]
RIP: 0010:vhost_process_iotlb_msg drivers/vhost/vhost.c:1024 [inline]
RIP: 0010:vhost_chr_write_iter drivers/vhost/vhost.c:1053 [inline]
RIP: 0010:vhost_chr_write_iter+0x4a9/0x1260 drivers/vhost/vhost.c:1037
ORIG_RAX: 0000000000000010
RSP: 0018:ffff88805769fb90 EFLAGS: 00010246
RAX: ffffffffffffffda RBX: 00007f0742e47c90 RCX: 00000000004592c9
RDX: 0000000020000100 RSI: 00000000800452d3 RDI: 0000000000000004
RAX: 0000000000000002 RBX: dffffc0000000000 RCX: 0000000000000000
RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
RDX: dffffc0000000000 RSI: ffffffff84a655b9 RDI: ffff8880576a5d80
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f0742e486d4
RBP: ffff88805769fcb0 R08: dffffc0000000000 R09: 0000000000000000
R13: 00000000004c19ba R14: 00000000004d4700 R15: 0000000000000003
R10: ffff88805769fb80 R11: ffff88805785e300 R12: ffff8880576aa480
R13: 0000000000000000 R14: ffff8880576a5cc0 R15: 0000000000000000
FS: 00007f4315a5d700(0000) GS:ffff8880aee00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000960004 CR3: 00000000a556e000 CR4: 00000000001406f0
Call Trace:
vhost_net_chr_write_iter+0x59/0x70 drivers/vhost/net.c:1360
call_write_iter include/linux/fs.h:1777 [inline]
new_sync_write fs/read_write.c:469 [inline]
__vfs_write+0x4a7/0x6b0 fs/read_write.c:482
vfs_write+0x198/0x500 fs/read_write.c:544
SYSC_write fs/read_write.c:590 [inline]
SyS_write+0xfd/0x230 fs/read_write.c:582
do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292
entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x4592c9
RSP: 002b:00007f4315a5cc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00000000004592c9
RDX: 0000000000000068 RSI: 0000000020000200 RDI: 0000000000000003
RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f4315a5d6d4
R13: 00000000004c939f R14: 00000000004e0400 R15: 00000000ffffffff
Code: ff ff 48 89 f9 48 c1 e9 03 80 3c 11 00 0f 85 9c 0c 00 00 49 8b 8e c0
00 00 00 48 ba 00 00 00 00 00 fc ff df 49 89 cf 48 c1 e9 03 <80> 3c 11 00
0f 85 61 0c 00 00 4d 8b 27 4d 85 e4 0f 84 27 09 00
RIP: vhost_del_umem_range drivers/vhost/vhost.c:953 [inline] RSP:
ffff88805769fb90
RIP: vhost_process_iotlb_msg drivers/vhost/vhost.c:1024 [inline] RSP:
ffff88805769fb90
RIP: vhost_chr_write_iter drivers/vhost/vhost.c:1053 [inline] RSP:
ffff88805769fb90
RIP: vhost_chr_write_iter+0x4a9/0x1260 drivers/vhost/vhost.c:1037 RSP:
ffff88805769fb90
---[ end trace c1e23b0d75e4f48a ]---


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[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.