VFS: Found a V7 FS (block size = 512) on device loop4
------------[ cut here ]------------
WARNING: CPU: 1 PID: 29643 at fs/inode.c:343 inc_nlink.cold+0x11/0x18 fs/inode.c:343
Kernel panic - not syncing: panic_on_warn set ...

CPU: 1 PID: 29643 Comm: syz-executor.4 Not tainted 4.19.192-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1fc/0x2ef lib/dump_stack.c:118
 panic+0x26a/0x50e kernel/panic.c:186
 __warn.cold+0x20/0x5a kernel/panic.c:541
 report_bug+0x262/0x2b0 lib/bug.c:183
 fixup_bug arch/x86/kernel/traps.c:178 [inline]
 fixup_bug arch/x86/kernel/traps.c:173 [inline]
 do_error_trap+0x1d7/0x310 arch/x86/kernel/traps.c:296
 invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:1038
RIP: 0010:inc_nlink.cold+0x11/0x18 fs/inode.c:343
ip6t_rpfilter: unknown options
Code: c0 74 04 3c 03 7e 08 8b 5d 48 e9 3f 66 b5 f9 4c 89 e7 e8 12 99 a4 f9 eb ee e8 cb d4 6e f9 48 c7 c7 00 ac 74 88 e8 98 ee fe ff <0f> 0b e9 81 67 b5 f9 e8 b3 d4 6e f9 48 8d 7b 40 b8 ff ff 37 00 48
RSP: 0018:ffff88808c167df0 EFLAGS: 00010282
RAX: 0000000000000024 RBX: ffff88803d66f948 RCX: 0000000000000000
RDX: 000000000000bb61 RSI: ffffffff814df6b1 RDI: ffffed101182cfb0
RBP: 0000000000000000 R08: 0000000000000024 R09: 0000000000000000
ip6t_rpfilter: unknown options
R10: 0000000000000005 R11: 0000000000000000 R12: ffff88803d66f990
R13: ffff88808d1c74a0 R14: 000000000000007e R15: 00000000000001ed
 inode_inc_link_count include/linux/fs.h:2101 [inline]
 sysv_mkdir+0x21/0x150 fs/sysv/namei.c:131
 vfs_mkdir+0x508/0x7a0 fs/namei.c:3819
 do_mkdirat+0x262/0x2d0 fs/namei.c:3842
 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x4656e7
Code: 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 b8 53 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f8d369eefa8 EFLAGS: 00000246 ORIG_RAX: 0000000000000053
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00000000004656e7
ip6t_rpfilter: unknown options
RDX: 0000000000000000 RSI: 00000000000001ff RDI: 0000000020000040
RBP: 00007f8d369ef040 R08: 0000000000000000 R09: 000000000104004a
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000020000000
R13: 0000000020000040 R14: 00007f8d369ef000 R15: 00000000200003c0
Kernel Offset: disabled
Rebooting in 86400 seconds..