Zero length message leads to an empty skb
 ... Log Wrap ... Log Wrap ... Log Wrap ...
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 ... Log Wrap ... Log Wrap ... Log Wrap ...
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find_entry called with index >= next_index
------------[ cut here ]------------
UBSAN: array-index-out-of-bounds in fs/jfs/jfs_dtree.c:1998:37
index -128 is out of range for type 'struct dtslot[128]'
CPU: 0 UID: 0 PID: 5317 Comm: syz.0.0 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 ubsan_epilogue+0xa/0x30 lib/ubsan.c:233
 __ubsan_handle_out_of_bounds+0xe8/0xf0 lib/ubsan.c:455
 dtSplitRoot+0xae9/0x16c0 fs/jfs/jfs_dtree.c:1998
 dtSplitUp fs/jfs/jfs_dtree.c:993 [inline]
 dtInsert+0xf19/0x5f10 fs/jfs/jfs_dtree.c:871
 jfs_create+0x75b/0xb10 fs/jfs/namei.c:138
 lookup_open fs/namei.c:4483 [inline]
 open_last_lookups fs/namei.c:4583 [inline]
 path_openat+0x1395/0x3860 fs/namei.c:4827
 do_file_open+0x23e/0x4a0 fs/namei.c:4859
 do_sys_openat2+0x113/0x200 fs/open.c:1366
 do_sys_open fs/open.c:1372 [inline]
 __do_sys_open fs/open.c:1380 [inline]
 __se_sys_open fs/open.c:1376 [inline]
 __x64_sys_open+0x11e/0x150 fs/open.c:1376
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7ffac499c629
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffac5833028 EFLAGS: 00000246 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 00007ffac4c16090 RCX: 00007ffac499c629
RDX: 0000000000000000 RSI: 000000000014507e RDI: 0000200000000780
RBP: 00007ffac4a32b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffac4c16128 R14: 00007ffac4c16090 R15: 00007ffefa9e59e8
 </TASK>
---[ end trace ]---