[ 37.944389][ T26] audit: type=1800 audit(1555808738.956:26): pid=7653 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="mcstrans" dev="sda1" ino=2457 res=0 [ 37.980953][ T26] audit: type=1800 audit(1555808738.966:27): pid=7653 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="restorecond" dev="sda1" ino=2436 res=0 [ 38.005861][ T26] audit: type=1800 audit(1555808738.966:28): pid=7653 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. [ 38.796189][ T26] audit: type=1800 audit(1555808739.856:29): pid=7653 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 Debian GNU/Linux 7 syzkaller ttyS0 Warning: Permanently added '10.128.0.217' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 51.720916][ T7808] ------------[ cut here ]------------ [ 51.726656][ T7808] percpu_ref_kill_and_confirm called more than once on io_ring_ctx_ref_free! [ 51.726902][ T7808] WARNING: CPU: 0 PID: 7808 at lib/percpu-refcount.c:335 percpu_ref_kill_and_confirm+0x341/0x3b0 [ 51.746254][ T7808] Kernel panic - not syncing: panic_on_warn set ... [ 51.752855][ T7808] CPU: 0 PID: 7808 Comm: syz-executor827 Not tainted 5.1.0-rc5+ #79 [ 51.761592][ T7808] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 51.771654][ T7808] Call Trace: [ 51.774959][ T7808] dump_stack+0x172/0x1f0 [ 51.779322][ T7808] ? percpu_ref_kill_and_confirm+0x340/0x3b0 [ 51.785318][ T7808] panic+0x2cb/0x65c [ 51.789234][ T7808] ? __warn_printk+0xf3/0xf3 [ 51.793916][ T7808] ? percpu_ref_kill_and_confirm+0x341/0x3b0 [ 51.799948][ T7808] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 51.806204][ T7808] ? __warn.cold+0x5/0x45 [ 51.810577][ T7808] ? __warn+0xe8/0x1d0 [ 51.814662][ T7808] ? percpu_ref_kill_and_confirm+0x341/0x3b0 [ 51.820657][ T7808] __warn.cold+0x20/0x45 [ 51.824907][ T7808] ? vprintk_emit+0x1ce/0x6d0 [ 51.829608][ T7808] ? percpu_ref_kill_and_confirm+0x341/0x3b0 [ 51.835596][ T7808] report_bug+0x263/0x2b0 [ 51.839943][ T7808] do_error_trap+0x11b/0x200 [ 51.844536][ T7808] do_invalid_op+0x37/0x50 [ 51.848961][ T7808] ? percpu_ref_kill_and_confirm+0x341/0x3b0 [ 51.855407][ T7808] invalid_op+0x14/0x20 [ 51.859573][ T7808] RIP: 0010:percpu_ref_kill_and_confirm+0x341/0x3b0 [ 51.866173][ T7808] 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 [ 51.885787][ T7808] RSP: 0018:ffff888093317cf0 EFLAGS: 00010082 [ 51.891859][ T7808] RAX: 0000000000000000 RBX: 0000607f5142f8db RCX: 0000000000000000 [ 51.899853][ T7808] RDX: 0000000000000000 RSI: ffffffff815afcf6 RDI: ffffed1012662f90 [ 51.907824][ T7808] RBP: ffff888093317d20 R08: ffff8880930ec440 R09: fffffbfff1133639 [ 51.915841][ T7808] R10: fffffbfff1133638 R11: ffffffff8899b1c3 R12: ffff888097e2b580 [ 51.924181][ T7808] R13: ffff888097e2b588 R14: 0000000000000286 R15: 0000000000000000 [ 51.932199][ T7808] ? vprintk_func+0x86/0x189 [ 51.936826][ T7808] __io_uring_register+0xa7/0x1fe0 [ 51.941973][ T7808] ? __mutex_lock+0x3cd/0x1310 [ 51.946767][ T7808] ? __x64_sys_io_uring_register+0x182/0x1f0 [ 51.952762][ T7808] ? mutex_trylock+0x1e0/0x1e0 [ 51.957542][ T7808] ? io_sq_wq_submit_work+0x10f0/0x10f0 [ 51.963102][ T7808] ? kasan_check_write+0x14/0x20 [ 51.968081][ T7808] __x64_sys_io_uring_register+0x193/0x1f0 [ 51.973909][ T7808] do_syscall_64+0x103/0x610 [ 51.978525][ T7808] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 51.984428][ T7808] RIP: 0033:0x4467c9 [ 51.988314][ T7808] 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 [ 52.007933][ T7808] RSP: 002b:00007f055ad1bdb8 EFLAGS: 00000246 ORIG_RAX: 00000000000001ab [ 52.016359][ T7808] RAX: ffffffffffffffda RBX: 00000000006dbc38 RCX: 00000000004467c9 [ 52.024327][ T7808] RDX: 0000000000000000 RSI: 0000000000000003 RDI: 0000000000000003 [ 52.032314][ T7808] RBP: 00000000006dbc30 R08: 00007f055ad1c700 R09: 0000000000000000 [ 52.044472][ T7808] R10: 0000000000000000 R11: 0000000000000246 R12: 00000000006dbc3c [ 52.052477][ T7808] R13: 00007ffe274eeacf R14: 00007f055ad1c9c0 R15: 20c49ba5e353f7cf [ 52.061414][ T7808] Kernel Offset: disabled [ 52.065861][ T7808] Rebooting in 86400 seconds..