[ 38.928719][ T26] audit: type=1800 audit(1555808415.017:29): pid=7690 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 '10.128.10.31' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 49.969804][ T7843] ------------[ cut here ]------------ [ 49.975426][ T7843] percpu_ref_kill_and_confirm called more than once on io_ring_ctx_ref_free! [ 49.975648][ T7843] WARNING: CPU: 0 PID: 7843 at lib/percpu-refcount.c:335 percpu_ref_kill_and_confirm+0x341/0x3b0 [ 49.994884][ T7843] Kernel panic - not syncing: panic_on_warn set ... [ 50.001466][ T7843] CPU: 0 PID: 7843 Comm: syz-executor056 Not tainted 5.1.0-rc5+ #77 [ 50.009432][ T7843] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 50.019499][ T7843] Call Trace: [ 50.022810][ T7843] dump_stack+0x172/0x1f0 [ 50.027142][ T7843] ? percpu_ref_kill_and_confirm+0x340/0x3b0 [ 50.033140][ T7843] panic+0x2cb/0x65c [ 50.037030][ T7843] ? __warn_printk+0xf3/0xf3 [ 50.041612][ T7843] ? percpu_ref_kill_and_confirm+0x341/0x3b0 [ 50.047584][ T7843] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 50.053842][ T7843] ? __warn.cold+0x5/0x45 [ 50.058168][ T7843] ? __warn+0xe8/0x1d0 [ 50.062445][ T7843] ? percpu_ref_kill_and_confirm+0x341/0x3b0 [ 50.068511][ T7843] __warn.cold+0x20/0x45 [ 50.072769][ T7843] ? vprintk_emit+0x1ce/0x6d0 [ 50.077440][ T7843] ? percpu_ref_kill_and_confirm+0x341/0x3b0 [ 50.083415][ T7843] report_bug+0x263/0x2b0 [ 50.087749][ T7843] do_error_trap+0x11b/0x200 [ 50.092332][ T7843] do_invalid_op+0x37/0x50 [ 50.096745][ T7843] ? percpu_ref_kill_and_confirm+0x341/0x3b0 [ 50.102741][ T7843] invalid_op+0x14/0x20 [ 50.106890][ T7843] RIP: 0010:percpu_ref_kill_and_confirm+0x341/0x3b0 [ 50.113459][ T7843] 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 [ 50.133080][ T7843] RSP: 0018:ffff8880a9327ce0 EFLAGS: 00010086 [ 50.139160][ T7843] RAX: 0000000000000000 RBX: 0000607f5142ef23 RCX: 0000000000000000 [ 50.147139][ T7843] RDX: 0000000000000000 RSI: ffffffff815afcf6 RDI: ffffed1015264f8e [ 50.155216][ T7843] RBP: ffff8880a9327d10 R08: ffff8880986b4700 R09: fffffbfff1133639 [ 50.163185][ T7843] R10: fffffbfff1133638 R11: ffffffff8899b1c3 R12: ffff8880a668e240 [ 50.171153][ T7843] R13: ffff8880a668e248 R14: 0000000000000286 R15: 0000000000000000 [ 50.179131][ T7843] ? vprintk_func+0x86/0x189 [ 50.183732][ T7843] __io_uring_register+0xa7/0x1fe0 [ 50.188839][ T7843] ? __mutex_lock+0x3cd/0x1310 [ 50.193598][ T7843] ? __ia32_sys_io_uring_register+0x182/0x1f0 [ 50.199662][ T7843] ? mutex_trylock+0x1e0/0x1e0 [ 50.204418][ T7843] ? io_sq_wq_submit_work+0x10f0/0x10f0 [ 50.209958][ T7843] ? calculate_sigpending+0x87/0xa0 [ 50.215154][ T7843] __ia32_sys_io_uring_register+0x193/0x1f0 [ 50.221076][ T7843] do_fast_syscall_32+0x281/0xc98 [ 50.226094][ T7843] entry_SYSENTER_compat+0x70/0x7f [ 50.231195][ T7843] RIP: 0023:0xf7f90869 [ 50.235267][ T7843] 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 [ 50.254886][ T7843] RSP: 002b:00000000f7f6b11c EFLAGS: 00000292 ORIG_RAX: 00000000000001ab [ 50.263296][ T7843] RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000000003 [ 50.271258][ T7843] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 [ 50.279223][ T7843] RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 [ 50.287213][ T7843] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 [ 50.295182][ T7843] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 [ 50.304016][ T7843] Kernel Offset: disabled [ 50.308428][ T7843] Rebooting in 86400 seconds..