[ 35.023781][ T26] audit: type=1800 audit(1555807712.120:27): pid=7447 uid=0 auid=4294967295 ses=4294967295 subj=_ op=collect_data cause=failed(directio) comm="startpar" name="restorecond" dev="sda1" ino=2436 res=0 [ 35.054539][ T26] audit: type=1800 audit(1555807712.200:28): pid=7447 uid=0 auid=4294967295 ses=4294967295 subj=_ 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. [ 35.843777][ T26] audit: type=1800 audit(1555807712.990:29): pid=7447 uid=0 auid=4294967295 ses=4294967295 subj=_ op=collect_data cause=failed(directio) comm="startpar" name="rc.local" dev="sda1" ino=2432 res=0 [ 35.863359][ T26] audit: type=1800 audit(1555807712.990:30): pid=7447 uid=0 auid=4294967295 ses=4294967295 subj=_ 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 '10.128.1.45' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 51.962242][ T7606] ------------[ cut here ]------------ [ 51.968092][ T7606] percpu_ref_kill_and_confirm called more than once on io_ring_ctx_ref_free! [ 51.968311][ T7606] WARNING: CPU: 0 PID: 7606 at lib/percpu-refcount.c:335 percpu_ref_kill_and_confirm+0x341/0x3b0 [ 51.987717][ T7606] Kernel panic - not syncing: panic_on_warn set ... [ 51.994288][ T7606] CPU: 0 PID: 7606 Comm: syz-executor922 Not tainted 5.1.0-rc5+ #78 [ 52.018736][ T7606] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 52.028773][ T7606] Call Trace: [ 52.032101][ T7606] dump_stack+0x172/0x1f0 [ 52.036510][ T7606] ? percpu_ref_kill_and_confirm+0x340/0x3b0 [ 52.042486][ T7606] panic+0x2cb/0x65c [ 52.046368][ T7606] ? __warn_printk+0xf3/0xf3 [ 52.050978][ T7606] ? percpu_ref_kill_and_confirm+0x341/0x3b0 [ 52.056950][ T7606] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 52.063188][ T7606] ? __warn.cold+0x5/0x45 [ 52.067499][ T7606] ? __warn+0xe8/0x1d0 [ 52.071551][ T7606] ? percpu_ref_kill_and_confirm+0x341/0x3b0 [ 52.077508][ T7606] __warn.cold+0x20/0x45 [ 52.081730][ T7606] ? vprintk_emit+0x1ce/0x6d0 [ 52.086391][ T7606] ? percpu_ref_kill_and_confirm+0x341/0x3b0 [ 52.092415][ T7606] report_bug+0x263/0x2b0 [ 52.096739][ T7606] do_error_trap+0x11b/0x200 [ 52.101452][ T7606] do_invalid_op+0x37/0x50 [ 52.105850][ T7606] ? percpu_ref_kill_and_confirm+0x341/0x3b0 [ 52.111879][ T7606] invalid_op+0x14/0x20 [ 52.116072][ T7606] RIP: 0010:percpu_ref_kill_and_confirm+0x341/0x3b0 [ 52.122641][ T7606] 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 [ 52.142227][ T7606] RSP: 0018:ffff88808da37cf0 EFLAGS: 00010082 [ 52.148276][ T7606] RAX: 0000000000000000 RBX: 0000607f5142eadb RCX: 0000000000000000 [ 52.156227][ T7606] RDX: 0000000000000000 RSI: ffffffff815afcf6 RDI: ffffed1011b46f90 [ 52.164189][ T7606] RBP: ffff88808da37d20 R08: ffff888091f382c0 R09: fffffbfff1133639 [ 52.172263][ T7606] R10: fffffbfff1133638 R11: ffffffff8899b1c3 R12: ffff888098eacc40 [ 52.180215][ T7606] R13: ffff888098eacc48 R14: 0000000000000286 R15: 0000000000000000 [ 52.188313][ T7606] ? vprintk_func+0x86/0x189 [ 52.193008][ T7606] __io_uring_register+0xa7/0x1fe0 [ 52.198110][ T7606] ? __mutex_lock+0x3cd/0x1310 [ 52.202899][ T7606] ? __x64_sys_io_uring_register+0x182/0x1f0 [ 52.208867][ T7606] ? mutex_trylock+0x1e0/0x1e0 [ 52.213618][ T7606] ? io_sq_wq_submit_work+0x10f0/0x10f0 [ 52.219148][ T7606] ? kasan_check_write+0x14/0x20 [ 52.224155][ T7606] __x64_sys_io_uring_register+0x193/0x1f0 [ 52.230147][ T7606] do_syscall_64+0x103/0x610 [ 52.234888][ T7606] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 52.240772][ T7606] RIP: 0033:0x4467c9 [ 52.244657][ T7606] 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 [ 52.264247][ T7606] RSP: 002b:00007fed453e0db8 EFLAGS: 00000246 ORIG_RAX: 00000000000001ab [ 52.272764][ T7606] RAX: ffffffffffffffda RBX: 00000000006dbc38 RCX: 00000000004467c9 [ 52.280718][ T7606] RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000003 [ 52.288803][ T7606] RBP: 00000000006dbc30 R08: 00007fed453e1700 R09: 0000000000000000 [ 52.296760][ T7606] R10: 0000000000000000 R11: 0000000000000246 R12: 00000000006dbc3c [ 52.304761][ T7606] R13: 00007fff8f0cb4af R14: 00007fed453e19c0 R15: 20c49ba5e353f7cf [ 52.314166][ T7606] Kernel Offset: disabled [ 52.318578][ T7606] Rebooting in 86400 seconds..