EXT4-fs (loop1): VFS: Can't find ext4 filesystem
VFS: could not find a valid V7 on loop1.
VFS: Found a V7 FS (block size = 512) on device loop2
VFS: could not find a valid V7 on loop1.
------------[ cut here ]------------
WARNING: CPU: 1 PID: 11611 at fs/inode.c:342 inc_nlink+0x113/0x130 syzkaller/managers/linux-4-14/kernel/fs/inode.c:342
Kernel panic - not syncing: panic_on_warn set ...

CPU: 1 PID: 11611 Comm: syz-executor.2 Not tainted 4.14.218-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack syzkaller/managers/linux-4-14/kernel/lib/dump_stack.c:17 [inline]
 dump_stack+0x1b2/0x281 syzkaller/managers/linux-4-14/kernel/lib/dump_stack.c:58
 panic+0x1f9/0x42d syzkaller/managers/linux-4-14/kernel/kernel/panic.c:183
 __warn.cold+0x20/0x44 syzkaller/managers/linux-4-14/kernel/kernel/panic.c:547
 report_bug+0x208/0x250 syzkaller/managers/linux-4-14/kernel/lib/bug.c:186
 fixup_bug syzkaller/managers/linux-4-14/kernel/arch/x86/kernel/traps.c:177 [inline]
 fixup_bug syzkaller/managers/linux-4-14/kernel/arch/x86/kernel/traps.c:172 [inline]
 do_error_trap+0x195/0x2d0 syzkaller/managers/linux-4-14/kernel/arch/x86/kernel/traps.c:295
 invalid_op+0x1b/0x40 syzkaller/managers/linux-4-14/kernel/arch/x86/entry/entry_64.S:964
RIP: 0010:inc_nlink+0x113/0x130 syzkaller/managers/linux-4-14/kernel/fs/inode.c:342
RSP: 0018:ffff888218fcfdf0 EFLAGS: 00010216
RAX: 0000000000040000 RBX: ffff888090542958 RCX: ffffc90005cde000
RDX: 0000000000000ad2 RSI: ffffffff818c2db3 RDI: ffff888090542a30
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffff8880905429a0
R13: ffff8880b1ddd720 R14: ffffffff87aa3640 R15: 0000000000000000
 inode_inc_link_count syzkaller/managers/linux-4-14/kernel/./include/linux/fs.h:2039 [inline]
 sysv_mkdir+0x21/0x120 syzkaller/managers/linux-4-14/kernel/fs/sysv/namei.c:136
 vfs_mkdir+0x463/0x6e0 syzkaller/managers/linux-4-14/kernel/fs/namei.c:3849
 SYSC_mkdirat syzkaller/managers/linux-4-14/kernel/fs/namei.c:3872 [inline]
 SyS_mkdirat+0x1fd/0x270 syzkaller/managers/linux-4-14/kernel/fs/namei.c:3856
 do_syscall_64+0x1d5/0x640 syzkaller/managers/linux-4-14/kernel/arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb
RIP: 0033:0x464c17
RSP: 002b:00007f8ed0b6cfa8 EFLAGS: 00000246 ORIG_RAX: 0000000000000053
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000464c17
RDX: 0000000000000000 RSI: 00000000000001ff RDI: 0000000020000300
RBP: 00007f8ed0b6d040 R08: 0000000000000000 R09: 0000000000200042
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000020000280
R13: 0000000020000300 R14: 00007f8ed0b6d000 R15: 0000000020000380
Kernel Offset: disabled
Rebooting in 86400 seconds..