[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [ 65.135809][ T26] audit: type=1800 audit(1585445135.617:25): pid=9384 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="cron" dev="sda1" ino=2414 res=0 [ 65.164501][ T26] audit: type=1800 audit(1585445135.617:26): pid=9384 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="mcstrans" dev="sda1" ino=2457 res=0 [ 65.194535][ T26] audit: type=1800 audit(1585445135.617:27): pid=9384 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 '10.128.0.164' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 88.046269][ T9537] IPVS: ftp: loaded support on port[0] = 21 [ 88.078889][ T9537] netlink: 16 bytes leftover after parsing attributes in process `syz-executor525'. [ 88.155850][ T9537] ------------[ cut here ]------------ [ 88.161344][ T9537] refcount_t: underflow; use-after-free. [ 88.167431][ T9537] WARNING: CPU: 1 PID: 9537 at lib/refcount.c:28 refcount_warn_saturate+0x1d1/0x1e0 [ 88.176846][ T9537] Kernel panic - not syncing: panic_on_warn set ... [ 88.183568][ T9537] CPU: 1 PID: 9537 Comm: syz-executor525 Not tainted 5.6.0-rc3-next-20200228-syzkaller #0 [ 88.193445][ T9537] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 88.203491][ T9537] Call Trace: [ 88.206784][ T9537] dump_stack+0x188/0x20d [ 88.211100][ T9537] ? refcount_warn_saturate+0x150/0x1e0 [ 88.216645][ T9537] panic+0x2e3/0x75c [ 88.220544][ T9537] ? add_taint.cold+0x16/0x16 [ 88.225231][ T9537] ? __probe_kernel_read+0x188/0x1d0 [ 88.230574][ T9537] ? __warn.cold+0x14/0x35 [ 88.235022][ T9537] ? __warn+0xd5/0x1c8 [ 88.239560][ T9537] ? refcount_warn_saturate+0x1d1/0x1e0 [ 88.245104][ T9537] __warn.cold+0x2f/0x35 [ 88.249409][ T9537] ? refcount_warn_saturate+0x1d1/0x1e0 [ 88.254974][ T9537] report_bug+0x27b/0x2f0 [ 88.259310][ T9537] do_error_trap+0x12b/0x220 [ 88.263897][ T9537] ? refcount_warn_saturate+0x1d1/0x1e0 [ 88.269440][ T9537] do_invalid_op+0x32/0x40 [ 88.273906][ T9537] ? refcount_warn_saturate+0x1d1/0x1e0 [ 88.279439][ T9537] invalid_op+0x23/0x30 [ 88.283722][ T9537] RIP: 0010:refcount_warn_saturate+0x1d1/0x1e0 [ 88.289917][ T9537] Code: e9 db fe ff ff 48 89 df e8 1c e7 1f fe e9 8a fe ff ff e8 12 c6 e2 fd 48 c7 c7 40 db 71 88 c6 05 b6 a9 f1 06 01 e8 77 91 b4 fd <0f> 0b e9 af fe ff ff 0f 1f 84 00 00 00 00 00 41 56 41 55 41 54 55 [ 88.309513][ T9537] RSP: 0018:ffffc90002027d38 EFLAGS: 00010286 [ 88.315559][ T9537] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 [ 88.323512][ T9537] RDX: 0000000000000000 RSI: ffffffff815c4e91 RDI: fffff52000404f99 [ 88.331468][ T9537] RBP: 0000000000000003 R08: ffff8880a8aac140 R09: 0000000000000000 [ 88.339431][ T9537] R10: 0000000000000000 R11: 0000000000000000 R12: ffff8880924d8040 [ 88.347387][ T9537] R13: ffff8880924d8044 R14: 00000000000002ac R15: ffff888093974ec0 [ 88.355359][ T9537] ? vprintk_func+0x81/0x17e [ 88.359940][ T9537] ? refcount_warn_saturate+0x1d1/0x1e0 [ 88.365479][ T9537] free_nsproxy+0x445/0x4a0 [ 88.369998][ T9537] switch_task_namespaces+0xaa/0xc0 [ 88.375188][ T9537] do_exit+0xb4e/0x2e10 [ 88.379414][ T9537] ? mm_update_next_owner+0x7a0/0x7a0 [ 88.384825][ T9537] ? up_read+0x1a8/0x750 [ 88.389083][ T9537] ? down_read_nested+0x430/0x430 [ 88.394102][ T9537] ? handle_mm_fault+0x29e/0x660 [ 88.399024][ T9537] do_group_exit+0x125/0x340 [ 88.403600][ T9537] __x64_sys_exit_group+0x3a/0x50 [ 88.408622][ T9537] do_syscall_64+0xf6/0x790 [ 88.413111][ T9537] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 88.418987][ T9537] RIP: 0033:0x43f998 [ 88.422866][ T9537] 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 [ 88.442464][ T9537] RSP: 002b:00007ffc87591078 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 [ 88.450856][ T9537] RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 000000000043f998 [ 88.458818][ T9537] RDX: 0000000000000001 RSI: 000000000000003c RDI: 0000000000000001 [ 88.466783][ T9537] RBP: 00000000004bfa10 R08: 00000000000000e7 R09: ffffffffffffffd0 [ 88.474758][ T9537] R10: 0000000120080522 R11: 0000000000000246 R12: 0000000000000001 [ 88.482713][ T9537] R13: 00000000006d11c0 R14: 0000000000000000 R15: 0000000000000000 [ 88.492275][ T9537] Kernel Offset: disabled [ 88.496653][ T9537] Rebooting in 86400 seconds..