[ 33.857019][ T26] audit: type=1800 audit(1555806861.482:27): pid=7426 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="restorecond" dev="sda1" ino=2436 res=0 [ 33.882437][ T26] audit: type=1800 audit(1555806861.492:28): pid=7426 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. [ 34.503974][ T26] audit: type=1800 audit(1555806862.202:29): pid=7426 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 [ 34.526025][ T26] audit: type=1800 audit(1555806862.202:30): pid=7426 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 '10.128.1.17' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 41.580566][ T7581] ------------[ cut here ]------------ [ 41.586189][ T7581] percpu_ref_kill_and_confirm called more than once on io_ring_ctx_ref_free! [ 41.586400][ T7581] WARNING: CPU: 1 PID: 7581 at lib/percpu-refcount.c:335 percpu_ref_kill_and_confirm+0x341/0x3b0 [ 41.605610][ T7581] Kernel panic - not syncing: panic_on_warn set ... [ 41.612178][ T7581] CPU: 1 PID: 7581 Comm: syz-executor152 Not tainted 5.1.0-rc5+ #79 [ 41.620141][ T7581] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 41.630178][ T7581] Call Trace: [ 41.633469][ T7581] dump_stack+0x172/0x1f0 [ 41.637802][ T7581] ? percpu_ref_kill_and_confirm+0x340/0x3b0 [ 41.643771][ T7581] panic+0x2cb/0x65c [ 41.647646][ T7581] ? __warn_printk+0xf3/0xf3 [ 41.652220][ T7581] ? percpu_ref_kill_and_confirm+0x341/0x3b0 [ 41.658175][ T7581] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 41.664404][ T7581] ? __warn.cold+0x5/0x45 [ 41.668719][ T7581] ? __warn+0xe8/0x1d0 [ 41.673524][ T7581] ? percpu_ref_kill_and_confirm+0x341/0x3b0 [ 41.679497][ T7581] __warn.cold+0x20/0x45 [ 41.683719][ T7581] ? vprintk_emit+0x1ce/0x6d0 [ 41.688388][ T7581] ? percpu_ref_kill_and_confirm+0x341/0x3b0 [ 41.694368][ T7581] report_bug+0x263/0x2b0 [ 41.698769][ T7581] do_error_trap+0x11b/0x200 [ 41.703340][ T7581] do_invalid_op+0x37/0x50 [ 41.707758][ T7581] ? percpu_ref_kill_and_confirm+0x341/0x3b0 [ 41.713717][ T7581] invalid_op+0x14/0x20 [ 41.717858][ T7581] RIP: 0010:percpu_ref_kill_and_confirm+0x341/0x3b0 [ 41.724651][ T7581] 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 [ 41.744241][ T7581] RSP: 0018:ffff888088ea7cf0 EFLAGS: 00010082 [ 41.750281][ T7581] RAX: 0000000000000000 RBX: 0000607f5142d403 RCX: 0000000000000000 [ 41.758230][ T7581] RDX: 0000000000000000 RSI: ffffffff815afcf6 RDI: ffffed10111d4f90 [ 41.766177][ T7581] RBP: ffff888088ea7d20 R08: ffff8880a81c8440 R09: fffffbfff1133639 [ 41.774126][ T7581] R10: fffffbfff1133638 R11: ffffffff8899b1c3 R12: ffff8880a99f1680 [ 41.782072][ T7581] R13: ffff8880a99f1688 R14: 0000000000000286 R15: 0000000000000000 [ 41.790048][ T7581] ? vprintk_func+0x86/0x189 [ 41.794619][ T7581] __io_uring_register+0xa7/0x1fe0 [ 41.799716][ T7581] ? __mutex_lock+0x3cd/0x1310 [ 41.804453][ T7581] ? __x64_sys_io_uring_register+0x182/0x1f0 [ 41.810412][ T7581] ? mutex_trylock+0x1e0/0x1e0 [ 41.815154][ T7581] ? io_sq_wq_submit_work+0x10f0/0x10f0 [ 41.820678][ T7581] ? kasan_check_write+0x14/0x20 [ 41.825593][ T7581] __x64_sys_io_uring_register+0x193/0x1f0 [ 41.831377][ T7581] do_syscall_64+0x103/0x610 [ 41.835969][ T7581] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 41.841839][ T7581] RIP: 0033:0x4467c9 [ 41.845711][ T7581] Code: e8 5c b3 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 0b 08 fc ff c3 66 2e 0f 1f 84 00 00 00 00 [ 41.865290][ T7581] RSP: 002b:00007f3ad5235db8 EFLAGS: 00000246 ORIG_RAX: 00000000000001ab [ 41.873677][ T7581] RAX: ffffffffffffffda RBX: 00000000006dbc38 RCX: 00000000004467c9 [ 41.881622][ T7581] RDX: 0000000000000000 RSI: 0000000000000003 RDI: 0000000000000003 [ 41.889569][ T7581] RBP: 00000000006dbc30 R08: 00007f3ad5236700 R09: 0000000000000000 [ 41.897603][ T7581] R10: 0000000000000000 R11: 0000000000000246 R12: 00000000006dbc3c [ 41.905551][ T7581] R13: 00007ffcca16f15f R14: 00007f3ad52369c0 R15: 20c49ba5e353f7cf [ 41.914712][ T7581] Kernel Offset: disabled [ 41.919108][ T7581] Rebooting in 86400 seconds..