Subject: [syzbot] kernel BUG in vhost_vsock_handle_tx_kick

From: syzbot <[email-masked]>
Date: Tue, 03 Jan 2023 16:08:51 -0800

Hello,

syzbot found the following issue on:

HEAD commit:    c76083fac3ba Add linux-next specific files for 20221226
git tree:       linux-next
console+strace: https://syzkaller.appspot.com/x/log.txt?x=1723da42480000
kernel config:  https://syzkaller.appspot.com/x/.config?x=c217c755f1884ab6
dashboard link: https://syzkaller.appspot.com/bug?extid=30b72abaa17c07fe39dd
compiler:       gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=14fc414c480000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=1604b20a480000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/e388f26357fd/disk-c76083fa.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/e24f0bae36d5/vmlinux-c76083fa.xz
kernel image: https://storage.googleapis.com/syzbot-assets/a5a69a059716/bzImage-c76083fa.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: [email-masked]

skbuff: skb_over_panic: text:ffffffff8768d6f1 len:25109 put:25109 head:ffff88802b5ac000 data:ffff88802b5ac02c tail:0x6241 end:0xc0 dev:<NULL>
------------[ cut here ]------------
kernel BUG at net/core/skbuff.c:121!
invalid opcode: 0000 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 5072 Comm: vhost-5071 Not tainted 6.2.0-rc1-next-20221226-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
RIP: 0010:skb_panic+0x16c/0x16e net/core/skbuff.c:121
Code: f7 4c 8b 4c 24 10 8b 4b 70 41 56 45 89 e8 4c 89 e2 41 57 48 89 ee 48 c7 c7 40 04 5b 8b ff 74 24 10 ff 74 24 20 e8 09 8e bf ff <0f> 0b e8 1a 67 82 f7 4c 8b 64 24 18 e8 80 3d d0 f7 48 c7 c1 40 12
RSP: 0018:ffffc90003cefca0 EFLAGS: 00010282
RAX: 000000000000008d RBX: ffff88802b674500 RCX: 0000000000000000
RDX: ffff8880236bba80 RSI: ffffffff81663b9c RDI: fffff5200079df86
RBP: ffffffff8b5b1280 R08: 000000000000008d R09: 0000000000000000
R10: 0000000080000000 R11: 0000000000000000 R12: ffffffff8768d6f1
R13: 0000000000006215 R14: ffffffff8b5b0400 R15: 00000000000000c0
FS:  0000000000000000(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020000380 CR3: 000000002985f000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 skb_over_panic net/core/skbuff.c:126 [inline]
 skb_put.cold+0x24/0x24 net/core/skbuff.c:2218
 virtio_vsock_skb_rx_put include/linux/virtio_vsock.h:56 [inline]
 vhost_vsock_alloc_skb drivers/vhost/vsock.c:374 [inline]
 vhost_vsock_handle_tx_kick+0xad1/0xd00 drivers/vhost/vsock.c:509
 vhost_worker+0x241/0x3e0 drivers/vhost/vhost.c:364
 kthread+0x2e8/0x3a0 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:skb_panic+0x16c/0x16e net/core/skbuff.c:121
Code: f7 4c 8b 4c 24 10 8b 4b 70 41 56 45 89 e8 4c 89 e2 41 57 48 89 ee 48 c7 c7 40 04 5b 8b ff 74 24 10 ff 74 24 20 e8 09 8e bf ff <0f> 0b e8 1a 67 82 f7 4c 8b 64 24 18 e8 80 3d d0 f7 48 c7 c1 40 12
RSP: 0018:ffffc90003cefca0 EFLAGS: 00010282
RAX: 000000000000008d RBX: ffff88802b674500 RCX: 0000000000000000
RDX: ffff8880236bba80 RSI: ffffffff81663b9c RDI: fffff5200079df86
RBP: ffffffff8b5b1280 R08: 000000000000008d R09: 0000000000000000
R10: 0000000080000000 R11: 0000000000000000 R12: ffffffff8768d6f1
R13: 0000000000006215 R14: ffffffff8b5b0400 R15: 00000000000000c0
FS:  0000000000000000(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fdc6f4a4298 CR3: 000000002985f000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400

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