VFS: could not find a valid V7 on loop4. VFS: Found a V7 FS (block size = 512) on device loop0 VFS: Found a V7 FS (block size = 512) on device loop5 ------------[ cut here ]------------ WARNING: CPU: 1 PID: 21125 at fs/inode.c:342 inc_nlink+0x113/0x130 fs/inode.c:342 Kernel panic - not syncing: panic_on_warn set ... CPU: 1 PID: 21125 Comm: syz-executor.5 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 lib/dump_stack.c:17 [inline] dump_stack+0x1b2/0x281 lib/dump_stack.c:58 panic+0x1f9/0x42d kernel/panic.c:183 __warn.cold+0x20/0x44 kernel/panic.c:547 report_bug+0x208/0x250 lib/bug.c:186 fixup_bug arch/x86/kernel/traps.c:177 [inline] fixup_bug arch/x86/kernel/traps.c:172 [inline] do_error_trap+0x195/0x2d0 arch/x86/kernel/traps.c:295 invalid_op+0x1b/0x40 arch/x86/entry/entry_64.S:964 RIP: 0010:inc_nlink+0x113/0x130 fs/inode.c:342 RSP: 0018:ffff88802bd37df0 EFLAGS: 00010212 RAX: 0000000000040000 RBX: ffff88808db8b5e8 RCX: ffffc900079ea000 RDX: 0000000000000653 RSI: ffffffff818c2db3 RDI: ffff88808db8b6c0 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: ffff88808db8b630 R13: ffff88808e4919e0 R14: ffffffff87aa3640 R15: 0000000000000000 inode_inc_link_count include/linux/fs.h:2039 [inline] sysv_mkdir+0x21/0x120 fs/sysv/namei.c:136 VFS: Found a V7 FS (block size = 512) on device loop3 vfs_mkdir+0x463/0x6e0 fs/namei.c:3849 SYSC_mkdirat fs/namei.c:3872 [inline] SyS_mkdirat+0x1fd/0x270 fs/namei.c:3856 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x465b09 RSP: 002b:00007fbec1915188 EFLAGS: 00000246 ORIG_RAX: 0000000000000053 RAX: ffffffffffffffda RBX: 000000000056bf60 RCX: 0000000000465b09 RDX: 0000000000000000 RSI: 0000000000000045 RDI: 0000000020000180 RBP: 00000000004b069f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056bf60 R13: 00007fff124c6c9f R14: 00007fbec1915300 R15: 0000000000022000 Kernel Offset: disabled Rebooting in 86400 seconds..