general protection fault in skb_clone

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 9d5c0b3a8e1a Linux 4.14.295
git tree: linux-4.14.y
console output: https://syzkaller.appspot.com/x/log.txt?x=13e0d752880000
kernel config: https://syzkaller.appspot.com/x/.config?x=746c079015a92425
dashboard link: https://syzkaller.appspot.com/bug?extid=0a20173d50b1d0a8dc18
compiler: gcc version 10.2.1 20210110 (Debian 10.2.1-6)
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=145dca3c880000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1028322c880000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/ed6fcf5895a2/disk-9d5c0b3a.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/341aa3534116/vmlinux-9d5c0b3a.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+0a2017...@syzkaller.appspotmail.com

RBP: 00007fffe50445f0 R08: 0000000000000000 R09: 0000000000000001
R10: 00007fffe5044367 R11: 0000000000000246 R12: 0000000000000003
R13: 00007fffe5044610 R14: 00007fffe5044600 R15: 00007fffe50445dc
kasan: CONFIG_KASAN_INLINE enabled
kasan: GPF could be caused by NULL-ptr deref or user memory access
general protection fault: 0000 [#1] PREEMPT SMP KASAN
Modules linked in:
CPU: 1 PID: 8203 Comm: syz-executor246 Not tainted 4.14.295-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/22/2022
task: ffff8880aff623c0 task.stack: ffff8880b00b8000
RIP: 0010:skb_clone+0xd8/0x9a0 net/core/skbuff.c:1283
RSP: 0018:ffff8880b00bf6b0 EFLAGS: 00010207
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000000011 RSI: 0000000001080020 RDI: 0000000000000000
RBP: 000000000000008e R08: 0000000000000140 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000001080020
R13: ffff8880a5191f00 R14: ffff8880ab9ab280 R15: dffffc0000000000
FS: 00005555557a3300(0000) GS:ffff8880ba500000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f0bd7160ed0 CR3: 000000009e7f7000 CR4: 00000000003406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
frame_get_stripped_skb net/hsr/hsr_forward.c:127 [inline]
hsr_forward_do net/hsr/hsr_forward.c:285 [inline]
hsr_forward_skb+0xdbb/0x19c0 net/hsr/hsr_forward.c:373
hsr_handle_frame+0x2e0/0x550 net/hsr/hsr_slave.c:50
__netif_receive_skb_core+0x730/0x2a30 net/core/dev.c:4428
__netif_receive_skb+0x27/0x1a0 net/core/dev.c:4512
netif_receive_skb_internal+0xd7/0x580 net/core/dev.c:4585
tun_rx_batched.isra.0+0x45c/0x710 drivers/net/tun.c:1234
tun_get_user+0x12ae/0x4710 drivers/net/tun.c:1594
tun_chr_write_iter+0xe8/0x1f0 drivers/net/tun.c:1625
call_write_iter include/linux/fs.h:1780 [inline]
new_sync_write fs/read_write.c:469 [inline]
__vfs_write+0x44c/0x630 fs/read_write.c:482
vfs_write+0x17f/0x4d0 fs/read_write.c:544
SYSC_write fs/read_write.c:590 [inline]
SyS_write+0xf2/0x210 fs/read_write.c:582
do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
entry_SYSCALL_64_after_hwframe+0x46/0xbb
RIP: 0033:0x7f0bd70ece83
RSP: 002b:00007fffe50445c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 00007f0bd70ece83
RDX: 0000000000000036 RSI: 0000000020000640 RDI: 00000000000000c8
RBP: 00007fffe50445f0 R08: 0000000000000000 R09: 0000000000000001
R10: 00007fffe5044367 R11: 0000000000000246 R12: 0000000000000003
R13: 00007fffe5044610 R14: 00007fffe5044600 R15: 00007fffe50445dc
Code: be 07 00 00 f6 45 03 08 0f 85 ff 05 00 00 e8 60 a9 95 fb 48 8d ab 8e 00 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 ea 48 c1 ea 03 <0f> b6 04 02 48 89 ea 83 e2 07 38 d0 7f 08 84 c0 0f 85 9f 07 00
RIP: skb_clone+0xd8/0x9a0 net/core/skbuff.c:1283 RSP: ffff8880b00bf6b0
---[ end trace 8e3080fb750ee8ac ]---
----------------
Code disassembly (best guess):
0: be 07 00 00 f6 mov $0xf6000007,%esi
5: 45 03 08 add (%r8),%r9d
8: 0f 85 ff 05 00 00 jne 0x60d
e: e8 60 a9 95 fb callq 0xfb95a973
13: 48 8d ab 8e 00 00 00 lea 0x8e(%rbx),%rbp
1a: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax
21: fc ff df
24: 48 89 ea mov %rbp,%rdx
27: 48 c1 ea 03 shr $0x3,%rdx
* 2b: 0f b6 04 02 movzbl (%rdx,%rax,1),%eax <-- trapping instruction
2f: 48 89 ea mov %rbp,%rdx
32: 83 e2 07 and $0x7,%edx
35: 38 d0 cmp %dl,%al
37: 7f 08 jg 0x41
39: 84 c0 test %al,%al
3b: 0f .byte 0xf
3c: 85 .byte 0x85
3d: 9f lahf
3e: 07 (bad)


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