[ 35.486346][ T26] audit: type=1800 audit(1555806606.966:27): pid=7538 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="restorecond" dev="sda1" ino=2436 res=0 [ 35.510236][ T26] audit: type=1800 audit(1555806606.966:28): pid=7538 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. [ 36.327468][ T26] audit: type=1800 audit(1555806607.866:29): pid=7538 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 [ 36.347907][ T26] audit: type=1800 audit(1555806607.866:30): pid=7538 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 '10.128.0.117' (ECDSA) to the list of known hosts. executing program executing program executing program syzkaller login: [ 61.882730][ T7697] ------------[ cut here ]------------ [ 61.888626][ T7697] percpu_ref_kill_and_confirm called more than once on io_ring_ctx_ref_free! [ 61.888912][ T7697] WARNING: CPU: 0 PID: 7697 at lib/percpu-refcount.c:335 percpu_ref_kill_and_confirm+0x341/0x3b0 [ 61.909811][ T7697] Kernel panic - not syncing: panic_on_warn set ... [ 61.916682][ T7697] CPU: 0 PID: 7697 Comm: syz-executor439 Not tainted 5.1.0-rc5+ #77 [ 61.925058][ T7697] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 61.935530][ T7697] Call Trace: [ 61.939004][ T7697] dump_stack+0x172/0x1f0 [ 61.943810][ T7697] ? percpu_ref_kill_and_confirm+0x340/0x3b0 [ 61.950258][ T7697] panic+0x2cb/0x65c [ 61.954653][ T7697] ? __warn_printk+0xf3/0xf3 [ 61.959739][ T7697] ? percpu_ref_kill_and_confirm+0x341/0x3b0 [ 61.966090][ T7697] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 61.972657][ T7697] ? __warn.cold+0x5/0x45 [ 61.977157][ T7697] ? __warn+0xe8/0x1d0 [ 61.981312][ T7697] ? percpu_ref_kill_and_confirm+0x341/0x3b0 [ 61.988666][ T7697] __warn.cold+0x20/0x45 [ 61.993550][ T7697] ? vprintk_emit+0x1ce/0x6d0 [ 61.998577][ T7697] ? percpu_ref_kill_and_confirm+0x341/0x3b0 [ 62.005454][ T7697] report_bug+0x263/0x2b0 [ 62.010181][ T7697] do_error_trap+0x11b/0x200 [ 62.014916][ T7697] do_invalid_op+0x37/0x50 [ 62.019684][ T7697] ? percpu_ref_kill_and_confirm+0x341/0x3b0 [ 62.026421][ T7697] invalid_op+0x14/0x20 [ 62.030669][ T7697] RIP: 0010:percpu_ref_kill_and_confirm+0x341/0x3b0 [ 62.037933][ T7697] 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 [ 62.059319][ T7697] RSP: 0018:ffff88809074fce0 EFLAGS: 00010086 [ 62.065936][ T7697] RAX: 0000000000000000 RBX: 0000607f5142d90b RCX: 0000000000000000 [ 62.075313][ T7697] RDX: 0000000000000000 RSI: ffffffff815afcf6 RDI: ffffed10120e9f8e [ 62.083856][ T7697] RBP: ffff88809074fd10 R08: ffff8880a3b38700 R09: fffffbfff1133639 [ 62.092799][ T7697] R10: fffffbfff1133638 R11: ffffffff8899b1c3 R12: ffff8880847a4600 [ 62.102730][ T7697] R13: ffff8880847a4608 R14: 0000000000000286 R15: 0000000000000000 [ 62.111376][ T7697] ? vprintk_func+0x86/0x189 [ 62.116405][ T7697] __io_uring_register+0xa7/0x1fe0 [ 62.122008][ T7697] ? __mutex_lock+0x3cd/0x1310 [ 62.126800][ T7697] ? __ia32_sys_io_uring_register+0x182/0x1f0 [ 62.134457][ T7697] ? mutex_trylock+0x1e0/0x1e0 [ 62.139475][ T7697] ? io_sq_wq_submit_work+0x10f0/0x10f0 [ 62.145372][ T7697] ? calculate_sigpending+0x87/0xa0 [ 62.150958][ T7697] __ia32_sys_io_uring_register+0x193/0x1f0 [ 62.157425][ T7697] do_fast_syscall_32+0x281/0xc98 [ 62.163982][ T7697] entry_SYSENTER_compat+0x70/0x7f [ 62.169955][ T7697] RIP: 0023:0xf7f35869 [ 62.174759][ T7697] Code: 85 d2 74 02 89 0a 5b 5d c3 8b 04 24 c3 8b 14 24 c3 8b 3c 24 c3 90 90 90 90 90 90 90 90 90 90 90 90 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 eb 0d 90 90 90 90 90 90 90 90 90 90 90 90 [ 62.195130][ T7697] RSP: 002b:00000000f7f101ec EFLAGS: 00000296 ORIG_RAX: 00000000000001ab [ 62.205248][ T7697] RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000000003 [ 62.214487][ T7697] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 [ 62.223156][ T7697] RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 [ 62.231819][ T7697] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 [ 62.240799][ T7697] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 [ 62.250743][ T7697] Kernel Offset: disabled [ 62.255556][ T7697] Rebooting in 86400 seconds..