[ OK ] Started Regular background program processing daemon. Starting OpenBSD Secure Shell server... Starting getty on tty2-tty6 if dbus and logind are not available... Starting Permit User Sessions... Starting System Logging Service... [ OK ] Found device /dev/ttyS0. [ OK ] Started Permit User Sessions. [ OK ] Started System Logging Service. [ OK ] Started OpenBSD Secure Shell server. [ OK ] Started getty on tty2-tty6 if dbus and logind are not available. [ OK ] Listening on Load/Save RF Kill Switch Status /dev/rfkill Watch. [ OK ] Started Getty on tty6. [ OK ] Started Getty on tty5. [ OK ] Started Getty on tty4. [ OK ] Started Getty on tty3. [ OK ] Started Getty on tty2. [ OK ] Started Getty on tty1. [ OK ] Started Serial Getty on ttyS0. [ OK ] Reached target Login Prompts. [ OK ] Reached target Multi-User System. [ OK ] Reached target Graphical Interface. Starting Update UTMP about System Runlevel Changes... Starting Load/Save RF Kill Switch Status... [ OK ] Started Update UTMP about System Runlevel Changes. [ OK ] Started Load/Save RF Kill Switch Status. Debian GNU/Linux 9 syzkaller ttyS0 Warning: Permanently added '10.128.10.63' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 74.222019][ T7081] IPVS: ftp: loaded support on port[0] = 21 [ 74.263969][ T7081] netlink: 16 bytes leftover after parsing attributes in process `syz-executor632'. [ 74.326675][ T7081] ------------[ cut here ]------------ [ 74.332414][ T7081] refcount_t: underflow; use-after-free. [ 74.338762][ T7081] WARNING: CPU: 1 PID: 7081 at lib/refcount.c:28 refcount_warn_saturate+0x1d1/0x1e0 [ 74.348144][ T7081] Kernel panic - not syncing: panic_on_warn set ... [ 74.354836][ T7081] CPU: 1 PID: 7081 Comm: syz-executor632 Not tainted 5.6.0-syzkaller #0 [ 74.363142][ T7081] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 74.373640][ T7081] Call Trace: [ 74.376990][ T7081] dump_stack+0x188/0x20d [ 74.381321][ T7081] ? refcount_warn_saturate+0x170/0x1e0 [ 74.387030][ T7081] panic+0x2e3/0x75c [ 74.391052][ T7081] ? add_taint.cold+0x16/0x16 [ 74.395734][ T7081] ? __probe_kernel_read+0x188/0x1d0 [ 74.400999][ T7081] ? __warn.cold+0x14/0x35 [ 74.405396][ T7081] ? __warn+0xd5/0x1c8 [ 74.409450][ T7081] ? refcount_warn_saturate+0x1d1/0x1e0 [ 74.414989][ T7081] __warn.cold+0x2f/0x35 [ 74.419219][ T7081] ? refcount_warn_saturate+0x1d1/0x1e0 [ 74.424753][ T7081] report_bug+0x27b/0x2f0 [ 74.429079][ T7081] do_error_trap+0x12b/0x220 [ 74.433647][ T7081] ? refcount_warn_saturate+0x1d1/0x1e0 [ 74.439181][ T7081] do_invalid_op+0x32/0x40 [ 74.443594][ T7081] ? refcount_warn_saturate+0x1d1/0x1e0 [ 74.449154][ T7081] invalid_op+0x23/0x30 [ 74.453289][ T7081] RIP: 0010:refcount_warn_saturate+0x1d1/0x1e0 [ 74.459448][ T7081] Code: e9 db fe ff ff 48 89 df e8 bc 14 1e fe e9 8a fe ff ff e8 62 8b e0 fd 48 c7 c7 c0 db 71 88 c6 05 45 5a f1 06 01 e8 87 03 b2 fd <0f> 0b e9 af fe ff ff 0f 1f 84 00 00 00 00 00 41 56 41 55 41 54 55 [ 74.479038][ T7081] RSP: 0018:ffffc900018c7d38 EFLAGS: 00010286 [ 74.485117][ T7081] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 [ 74.493079][ T7081] RDX: 0000000000000000 RSI: ffffffff815ca081 RDI: fffff52000318f99 [ 74.501056][ T7081] RBP: 0000000000000003 R08: ffff88809d6ca3c0 R09: ffffed1015ce66a1 [ 74.509023][ T7081] R10: ffff8880ae733507 R11: ffffed1015ce66a0 R12: ffff88809d4da040 [ 74.518833][ T7081] R13: ffff88809d4da044 R14: 00000000000002ab R15: ffff888092fda0c0 [ 74.527429][ T7081] ? vprintk_func+0x81/0x17e [ 74.532018][ T7081] ? refcount_warn_saturate+0x1d1/0x1e0 [ 74.537755][ T7081] free_nsproxy+0x445/0x4a0 [ 74.542363][ T7081] switch_task_namespaces+0xaa/0xc0 [ 74.547563][ T7081] do_exit+0xb2f/0x2dd0 [ 74.551730][ T7081] ? mm_update_next_owner+0x7a0/0x7a0 [ 74.557106][ T7081] ? up_read+0x1ab/0x750 [ 74.561506][ T7081] ? mark_held_locks+0x9f/0xe0 [ 74.566302][ T7081] ? down_read_nested+0x420/0x420 [ 74.571359][ T7081] ? handle_mm_fault+0x491/0xa10 [ 74.576293][ T7081] do_group_exit+0x125/0x340 [ 74.580879][ T7081] __x64_sys_exit_group+0x3a/0x50 [ 74.585919][ T7081] do_syscall_64+0xf6/0x7d0 [ 74.590410][ T7081] entry_SYSCALL_64_after_hwframe+0x49/0xb3 [ 74.596307][ T7081] RIP: 0033:0x43f998 [ 74.600188][ T7081] Code: Bad RIP value. [ 74.604234][ T7081] RSP: 002b:00007fff08450138 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 [ 74.612637][ T7081] RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 000000000043f998 [ 74.620601][ T7081] RDX: 0000000000000001 RSI: 000000000000003c RDI: 0000000000000001 [ 74.628561][ T7081] RBP: 00000000004bfa10 R08: 00000000000000e7 R09: ffffffffffffffd0 [ 74.636535][ T7081] R10: 0000000120080522 R11: 0000000000000246 R12: 0000000000000001 [ 74.644526][ T7081] R13: 00000000006d11c0 R14: 0000000000000000 R15: 0000000000000000 [ 74.654358][ T7081] Kernel Offset: disabled [ 74.658856][ T7081] Rebooting in 86400 seconds..