[ 37.183831][ T26] audit: type=1800 audit(1555810487.839:27): pid=7686 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="restorecond" dev="sda1" ino=2436 res=0 [ 37.211690][ T26] audit: type=1800 audit(1555810487.839:28): pid=7686 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="ssh" dev="sda1" ino=2417 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. [ 37.860104][ T26] audit: type=1800 audit(1555810488.579:29): pid=7686 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="rc.local" dev="sda1" ino=2432 res=0 [ 37.880445][ T26] audit: type=1800 audit(1555810488.579:30): pid=7686 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="rmnologin" dev="sda1" ino=2423 res=0 Debian GNU/Linux 7 syzkaller ttyS0 Warning: Permanently added '10.128.0.84' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 45.574686][ T7841] IPVS: ftp: loaded support on port[0] = 21 [ 45.651203][ T7843] ------------[ cut here ]------------ [ 45.656814][ T7843] percpu_ref_kill_and_confirm called more than once on io_ring_ctx_ref_free! [ 45.657033][ T7843] WARNING: CPU: 1 PID: 7843 at lib/percpu-refcount.c:335 percpu_ref_kill_and_confirm+0x341/0x3b0 [ 45.676249][ T7843] Kernel panic - not syncing: panic_on_warn set ... [ 45.682817][ T7843] CPU: 1 PID: 7843 Comm: syz-executor938 Not tainted 5.1.0-rc5+ #79 [ 45.690791][ T7843] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 45.700823][ T7843] Call Trace: [ 45.704099][ T7843] dump_stack+0x172/0x1f0 [ 45.708431][ T7843] ? percpu_ref_kill_and_confirm+0x340/0x3b0 [ 45.714395][ T7843] panic+0x2cb/0x65c [ 45.718272][ T7843] ? __warn_printk+0xf3/0xf3 [ 45.722849][ T7843] ? percpu_ref_kill_and_confirm+0x341/0x3b0 [ 45.728809][ T7843] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 45.735030][ T7843] ? __warn.cold+0x5/0x45 [ 45.739347][ T7843] ? __warn+0xe8/0x1d0 [ 45.743414][ T7843] ? percpu_ref_kill_and_confirm+0x341/0x3b0 [ 45.749375][ T7843] __warn.cold+0x20/0x45 [ 45.753624][ T7843] ? vprintk_emit+0x1ce/0x6d0 [ 45.758289][ T7843] ? percpu_ref_kill_and_confirm+0x341/0x3b0 [ 45.764251][ T7843] report_bug+0x263/0x2b0 [ 45.768566][ T7843] do_error_trap+0x11b/0x200 [ 45.773138][ T7843] do_invalid_op+0x37/0x50 [ 45.777534][ T7843] ? percpu_ref_kill_and_confirm+0x341/0x3b0 [ 45.783494][ T7843] invalid_op+0x14/0x20 [ 45.787644][ T7843] RIP: 0010:percpu_ref_kill_and_confirm+0x341/0x3b0 [ 45.794211][ T7843] Code: 42 e0 2a 06 01 48 89 fa 48 c1 ea 03 80 3c 02 00 75 76 49 8b 54 24 10 48 c7 c6 a0 71 a1 87 48 c7 c7 40 71 a1 87 e8 ad 92 13 fe <0f> 0b 48 b8 00 00 00 00 00 fc ff df 4c 89 ea 48 c1 ea 03 80 3c 02 [ 45.813809][ T7843] RSP: 0018:ffff8880a5137cf0 EFLAGS: 00010082 [ 45.819872][ T7843] RAX: 0000000000000000 RBX: 0000607f5142e71b RCX: 0000000000000000 [ 45.827838][ T7843] RDX: 0000000000000000 RSI: ffffffff815afcf6 RDI: ffffed1014a26f90 [ 45.835803][ T7843] RBP: ffff8880a5137d20 R08: ffff8880862b4480 R09: fffffbfff1133639 [ 45.843772][ T7843] R10: fffffbfff1133638 R11: ffffffff8899b1c3 R12: ffff888092b8b600 [ 45.851740][ T7843] R13: ffff888092b8b608 R14: 0000000000000286 R15: 0000000000000000 [ 45.859728][ T7843] ? vprintk_func+0x86/0x189 [ 45.864325][ T7843] __io_uring_register+0xa7/0x1fe0 [ 45.869434][ T7843] ? __mutex_lock+0x3cd/0x1310 [ 45.874196][ T7843] ? __x64_sys_io_uring_register+0x182/0x1f0 [ 45.880176][ T7843] ? mutex_trylock+0x1e0/0x1e0 [ 45.884953][ T7843] ? io_sq_wq_submit_work+0x10f0/0x10f0 [ 45.890506][ T7843] ? kasan_check_write+0x14/0x20 [ 45.895449][ T7843] __x64_sys_io_uring_register+0x193/0x1f0 [ 45.901258][ T7843] do_syscall_64+0x103/0x610 [ 45.905851][ T7843] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 45.911734][ T7843] RIP: 0033:0x4461f9 [ 45.915626][ T7843] Code: e8 6c bf 02 00 48 83 c4 18 c3 0f 1f 80 00 00 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 3b 11 fc ff c3 66 2e 0f 1f 84 00 00 00 00 [ 45.935242][ T7843] RSP: 002b:00007f15e309cdb8 EFLAGS: 00000246 ORIG_RAX: 00000000000001ab [ 45.943651][ T7843] RAX: ffffffffffffffda RBX: 00000000006f0038 RCX: 00000000004461f9 [ 45.951625][ T7843] RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000003 [ 45.959590][ T7843] RBP: 00000000006f0030 R08: 00007f15e309d700 R09: 0000000000000000 [ 45.967559][ T7843] R10: 0000000000000000 R11: 0000000000000246 R12: 00000000006f003c [ 45.975523][ T7843] R13: 00000000007ffe8f R14: 00007f15e309d9c0 R15: 0000000000000000 [ 45.984498][ T7843] Kernel Offset: disabled [ 45.988894][ T7843] Rebooting in 86400 seconds..