[ OK ] Started Serial Getty on ttyS0. [ OK ] Reached target Login Prompts. [ OK ] Started OpenBSD Secure Shell server. [ OK ] Listening on Load/Save RF Kill Switch Status /dev/rfkill Watch. [ OK ] Reached target Multi-User System. [ OK ] Reached target Graphical Interface. Starting Update UTMP about System Runlevel Changes... [ OK ] Started Update UTMP about System Runlevel Changes. Starting Load/Save RF Kill Switch Status... [ OK ] Started Load/Save RF Kill Switch Status. Debian GNU/Linux 9 syzkaller ttyS0 Warning: Permanently added '10.128.0.136' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 28.689740] VFS: Found a V7 FS (block size = 512) on device loop0 [ 28.702120] ------------[ cut here ]------------ [ 28.706987] WARNING: CPU: 0 PID: 7988 at fs/inode.c:342 inc_nlink+0x113/0x130 [ 28.714261] Kernel panic - not syncing: panic_on_warn set ... [ 28.714261] [ 28.721620] CPU: 0 PID: 7988 Comm: syz-executor331 Not tainted 4.14.206-syzkaller #0 [ 28.729596] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 28.739102] Call Trace: [ 28.741669] dump_stack+0x1b2/0x283 [ 28.745282] panic+0x1f9/0x42d [ 28.748464] ? add_taint.cold+0x16/0x16 [ 28.752434] ? inc_nlink+0x113/0x130 [ 28.756142] ? inc_nlink+0x113/0x130 [ 28.759833] __warn.cold+0x20/0x4b [ 28.763348] ? ist_end_non_atomic+0x10/0x10 [ 28.767645] ? inc_nlink+0x113/0x130 [ 28.771333] report_bug+0x208/0x249 [ 28.774936] do_error_trap+0x195/0x2d0 [ 28.778799] ? math_error+0x2d0/0x2d0 [ 28.782576] ? _raw_spin_unlock_irqrestore+0x66/0xe0 [ 28.787656] ? debug_check_no_obj_freed+0x2c0/0x674 [ 28.792663] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 28.797520] invalid_op+0x1b/0x40 [ 28.800952] RIP: 0010:inc_nlink+0x113/0x130 [ 28.805262] RSP: 0018:ffff8880b32efdf0 EFLAGS: 00010297 [ 28.810608] RAX: ffff88809586a640 RBX: ffff88808e319958 RCX: 1ffffffff0f545c1 [ 28.817856] RDX: 0000000000000000 RSI: ffff88809824e6e0 RDI: ffff88808e319a30 [ 28.825112] RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 [ 28.832361] R10: 0000000000000000 R11: 0000000000000000 R12: ffff88808e3199a0 [ 28.839621] R13: ffff88809824e6e0 R14: ffffffff87aa2dc0 R15: 0000000000000000 [ 28.846880] sysv_mkdir+0x21/0x120 [ 28.850399] vfs_mkdir+0x463/0x6e0 [ 28.853913] SyS_mkdirat+0x1fd/0x270 [ 28.857615] ? SyS_mknod+0x30/0x30 [ 28.861140] ? __close_fd+0x159/0x230 [ 28.864917] ? do_syscall_64+0x4c/0x640 [ 28.868864] ? SyS_mknod+0x30/0x30 [ 28.872396] do_syscall_64+0x1d5/0x640 [ 28.876280] entry_SYSCALL_64_after_hwframe+0x46/0xbb [ 28.881445] RIP: 0033:0x444439 [ 28.884611] RSP: 002b:00007ffd6cbee618 EFLAGS: 00000246 ORIG_RAX: 0000000000000102 [ 28.892293] RAX: ffffffffffffffda RBX: 00000000004002e0 RCX: 0000000000444439 [ 28.899538] RDX: 00000000000000b8 RSI: 0000000020000040 RDI: 0000000000000005 [ 28.906804] RBP: 00000000006cf018 R08: 00007ffd00000015 R09: 00000000004002e0 [ 28.914047] R10: 00007ffd6cbee4c0 R11: 0000000000000246 R12: 0000000000402020 [ 28.922105] R13: 00000000004020b0 R14: 0000000000000000 R15: 0000000000000000 [ 28.930232] Kernel Offset: disabled [ 28.933877] Rebooting in 86400 seconds..