[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [ 76.085526][ T27] audit: type=1800 audit(1584100705.663:25): pid=9554 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="cron" dev="sda1" ino=2414 res=0 [ 76.105661][ T27] audit: type=1800 audit(1584100705.663:26): pid=9554 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="mcstrans" dev="sda1" ino=2457 res=0 [ 76.142924][ T27] audit: type=1800 audit(1584100705.673:27): pid=9554 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="restorecond" dev="sda1" ino=2436 res=0 [....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 Warning: Permanently added '10.128.0.209' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 100.446657][ T9710] IPVS: ftp: loaded support on port[0] = 21 [ 100.479210][ T9710] netlink: 16 bytes leftover after parsing attributes in process `syz-executor928'. [ 100.542848][ T9710] ------------[ cut here ]------------ [ 100.548478][ T9710] refcount_t: underflow; use-after-free. [ 100.554479][ T9710] WARNING: CPU: 1 PID: 9710 at lib/refcount.c:28 refcount_warn_saturate+0x1d1/0x1e0 [ 100.564402][ T9710] Kernel panic - not syncing: panic_on_warn set ... [ 100.570987][ T9710] CPU: 1 PID: 9710 Comm: syz-executor928 Not tainted 5.6.0-rc3-syzkaller #0 [ 100.579668][ T9710] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 100.589725][ T9710] Call Trace: [ 100.593026][ T9710] dump_stack+0x188/0x20d [ 100.597341][ T9710] ? refcount_warn_saturate+0x1b0/0x1e0 [ 100.602877][ T9710] panic+0x2e3/0x75c [ 100.606752][ T9710] ? add_taint.cold+0x16/0x16 [ 100.611418][ T9710] ? __probe_kernel_read+0x188/0x1d0 [ 100.616693][ T9710] ? __warn.cold+0x14/0x35 [ 100.621216][ T9710] ? __warn+0xd5/0x1c8 [ 100.625340][ T9710] ? refcount_warn_saturate+0x1d1/0x1e0 [ 100.631053][ T9710] __warn.cold+0x2f/0x35 [ 100.635307][ T9710] ? refcount_warn_saturate+0x1d1/0x1e0 [ 100.640934][ T9710] report_bug+0x27b/0x2f0 [ 100.645274][ T9710] do_error_trap+0x12b/0x220 [ 100.649867][ T9710] ? refcount_warn_saturate+0x1d1/0x1e0 [ 100.655413][ T9710] do_invalid_op+0x32/0x40 [ 100.659821][ T9710] ? refcount_warn_saturate+0x1d1/0x1e0 [ 100.665372][ T9710] invalid_op+0x23/0x30 [ 100.669513][ T9710] RIP: 0010:refcount_warn_saturate+0x1d1/0x1e0 [ 100.675657][ T9710] Code: e9 db fe ff ff 48 89 df e8 cc 15 21 fe e9 8a fe ff ff e8 82 70 e4 fd 48 c7 c7 00 a5 51 88 c6 05 57 a5 d3 06 01 e8 b7 83 b6 fd <0f> 0b e9 af fe ff ff 0f 1f 84 00 00 00 00 00 41 56 41 55 41 54 55 [ 100.695252][ T9710] RSP: 0018:ffffc90002067d50 EFLAGS: 00010286 [ 100.701316][ T9710] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 [ 100.709278][ T9710] RDX: 0000000000000000 RSI: ffffffff815bf411 RDI: fffff5200040cf9c [ 100.717230][ T9710] RBP: 0000000000000003 R08: ffff888093290140 R09: 0000000000000000 [ 100.725181][ T9710] R10: 0000000000000000 R11: 0000000000000000 R12: ffff88808fbba040 [ 100.733181][ T9710] R13: ffff88808fbba044 R14: 0000000000000001 R15: 00000000000002aa [ 100.741234][ T9710] ? vprintk_func+0x81/0x17e [ 100.746636][ T9710] free_nsproxy+0x445/0x4a0 [ 100.751167][ T9710] switch_task_namespaces+0xaa/0xc0 [ 100.756501][ T9710] do_exit+0xb54/0x2db0 [ 100.760697][ T9710] ? mm_update_next_owner+0x7a0/0x7a0 [ 100.766061][ T9710] ? up_read+0x1ab/0x750 [ 100.770297][ T9710] ? mark_held_locks+0x9f/0xe0 [ 100.775087][ T9710] ? down_read_non_owner+0x470/0x470 [ 100.780359][ T9710] ? handle_mm_fault+0x491/0xa10 [ 100.785283][ T9710] do_group_exit+0x125/0x340 [ 100.789862][ T9710] __x64_sys_exit_group+0x3a/0x50 [ 100.794868][ T9710] do_syscall_64+0xf6/0x790 [ 100.799367][ T9710] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 100.805252][ T9710] RIP: 0033:0x43f998 [ 100.809127][ T9710] Code: 24 38 80 f9 3a 0f 85 5f 01 00 00 48 8d 74 24 34 48 8d 7c 24 38 83 ea 01 89 54 24 34 e8 61 f8 ff ff 83 f8 3c 41 89 c1 0f 87 3d <01> 00 00 8b 4c 24 34 85 c9 0f 8e 59 01 00 00 48 8b 54 24 38 c7 44 [ 100.828722][ T9710] RSP: 002b:00007ffc58cdb9e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 [ 100.837124][ T9710] RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 000000000043f998 [ 100.845095][ T9710] RDX: 0000000000000001 RSI: 000000000000003c RDI: 0000000000000001 [ 100.853045][ T9710] RBP: 00000000004bfa10 R08: 00000000000000e7 R09: ffffffffffffffd0 [ 100.861008][ T9710] R10: 0000000120080522 R11: 0000000000000246 R12: 0000000000000001 [ 100.868966][ T9710] R13: 00000000006d11c0 R14: 0000000000000000 R15: 0000000000000000 [ 100.878447][ T9710] Kernel Offset: disabled [ 100.882844][ T9710] Rebooting in 86400 seconds..