[ 34.239062][ T26] audit: type=1800 audit(1555821146.742:27): pid=7377 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="restorecond" dev="sda1" ino=2436 res=0 [ 34.271340][ T26] audit: type=1800 audit(1555821146.822:28): pid=7377 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. [ 34.990792][ T26] audit: type=1800 audit(1555821147.542:29): pid=7377 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 [ 35.011293][ T26] audit: type=1800 audit(1555821147.552:30): pid=7377 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 '10.128.0.87' (ECDSA) to the list of known hosts. executing program executing program syzkaller login: [ 44.723739][ T7534] ------------[ cut here ]------------ [ 44.729483][ T7534] percpu_ref_kill_and_confirm called more than once on io_ring_ctx_ref_free! [ 44.729690][ T7534] WARNING: CPU: 1 PID: 7534 at lib/percpu-refcount.c:335 percpu_ref_kill_and_confirm+0x341/0x3b0 [ 44.749117][ T7534] Kernel panic - not syncing: panic_on_warn set ... [ 44.755701][ T7534] CPU: 1 PID: 7534 Comm: syz-executor009 Not tainted 5.1.0-rc5+ #78 [ 44.763762][ T7534] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 44.773808][ T7534] Call Trace: [ 44.777268][ T7534] dump_stack+0x172/0x1f0 [ 44.781620][ T7534] ? percpu_ref_kill_and_confirm+0x340/0x3b0 [ 44.787594][ T7534] panic+0x2cb/0x65c [ 44.791677][ T7534] ? __warn_printk+0xf3/0xf3 [ 44.796269][ T7534] ? percpu_ref_kill_and_confirm+0x341/0x3b0 [ 44.802329][ T7534] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 44.808571][ T7534] ? __warn.cold+0x5/0x45 [ 44.812947][ T7534] ? __warn+0xe8/0x1d0 [ 44.817026][ T7534] ? percpu_ref_kill_and_confirm+0x341/0x3b0 [ 44.823003][ T7534] __warn.cold+0x20/0x45 [ 44.827234][ T7534] ? vprintk_emit+0x1ce/0x6d0 [ 44.831896][ T7534] ? percpu_ref_kill_and_confirm+0x341/0x3b0 [ 44.837863][ T7534] report_bug+0x263/0x2b0 [ 44.842189][ T7534] do_error_trap+0x11b/0x200 [ 44.846772][ T7534] do_invalid_op+0x37/0x50 [ 44.851297][ T7534] ? percpu_ref_kill_and_confirm+0x341/0x3b0 [ 44.857394][ T7534] invalid_op+0x14/0x20 [ 44.861535][ T7534] RIP: 0010:percpu_ref_kill_and_confirm+0x341/0x3b0 [ 44.868199][ T7534] 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 [ 44.887906][ T7534] RSP: 0018:ffff8880a4557cf0 EFLAGS: 00010082 [ 44.893962][ T7534] RAX: 0000000000000000 RBX: 0000607f5142d66b RCX: 0000000000000000 [ 44.902016][ T7534] RDX: 0000000000000000 RSI: ffffffff815afcf6 RDI: ffffed10148aaf90 [ 44.910003][ T7534] RBP: ffff8880a4557d20 R08: ffff88808dc7c140 R09: fffffbfff1133639 [ 44.918074][ T7534] R10: fffffbfff1133638 R11: ffffffff8899b1c3 R12: ffff8880a9b7c480 [ 44.926044][ T7534] R13: ffff8880a9b7c488 R14: 0000000000000286 R15: 0000000000000000 [ 44.934116][ T7534] ? vprintk_func+0x86/0x189 [ 44.938709][ T7534] __io_uring_register+0xa7/0x1fe0 [ 44.943842][ T7534] ? __mutex_lock+0x3cd/0x1310 [ 44.948610][ T7534] ? __x64_sys_io_uring_register+0x182/0x1f0 [ 44.954581][ T7534] ? mutex_trylock+0x1e0/0x1e0 [ 44.959345][ T7534] ? io_sq_wq_submit_work+0x10f0/0x10f0 [ 44.964881][ T7534] ? kasan_check_write+0x14/0x20 [ 44.969803][ T7534] __x64_sys_io_uring_register+0x193/0x1f0 [ 44.975594][ T7534] do_syscall_64+0x103/0x610 [ 44.980278][ T7534] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 44.986155][ T7534] RIP: 0033:0x4467c9 [ 44.990204][ T7534] 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 [ 45.009966][ T7534] RSP: 002b:00007f756c5c8db8 EFLAGS: 00000246 ORIG_RAX: 00000000000001ab [ 45.018375][ T7534] RAX: ffffffffffffffda RBX: 00000000006dbc38 RCX: 00000000004467c9 [ 45.026420][ T7534] RDX: 0000000000000000 RSI: 0000000000000003 RDI: 0000000000000003 [ 45.034392][ T7534] RBP: 00000000006dbc30 R08: 00007f756c5c9700 R09: 0000000000000000 [ 45.042367][ T7534] R10: 0000000000000000 R11: 0000000000000246 R12: 00000000006dbc3c [ 45.050324][ T7534] R13: 00007fff8f71d5ff R14: 00007f756c5c99c0 R15: 20c49ba5e353f7cf [ 45.059889][ T7534] Kernel Offset: disabled [ 45.064334][ T7534] Rebooting in 86400 seconds..