[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[1G[[32m ok [39;49m8[?25h[?0c.
[ 55.516382][ T26] audit: type=1800 audit(1568156739.848:25): pid=8585 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="cron" dev="sda1" ino=2414 res=0
[ 55.537987][ T26] audit: type=1800 audit(1568156739.848:26): pid=8585 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="mcstrans" dev="sda1" ino=2457 res=0
[ 55.560097][ T26] audit: type=1800 audit(1568156739.848:27): pid=8585 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="restorecond" dev="sda1" ino=2436 res=0
[....] Starting periodic command scheduler: cron[?25l[?1c7[1G[[32m ok [39;49m8[?25h[?0c.
[....] Starting OpenBSD Secure Shell server: sshd[?25l[?1c7[1G[[32m ok [39;49m8[?25h[?0c.
Debian GNU/Linux 7 syzkaller ttyS0
Warning: Permanently added '10.128.0.176' (ECDSA) to the list of known hosts.
executing program
syzkaller login: [ 63.637493][ C0]
[ 63.639957][ C0] ========================================================
[ 63.647284][ C0] WARNING: possible irq lock inversion dependency detected
[ 63.655538][ C0] 5.3.0-rc6-next-20190830 #75 Not tainted
[ 63.661387][ C0] --------------------------------------------------------
[ 63.668766][ C0] swapper/0/0 just changed the state of lock:
[ 63.675026][ C0] ffff8880a56dbb58 (&(&ctx->ctx_lock)->rlock){..-.}, at: free_ioctx_users+0x2d/0x490
[ 63.684687][ C0] but this lock took another, SOFTIRQ-unsafe lock in the past:
[ 63.692202][ C0] (&fiq->waitq){+.+.}
[ 63.692211][ C0]
[ 63.692211][ C0]
[ 63.692211][ C0] and interrupts could create inverse lock ordering between them.
[ 63.692211][ C0]
[ 63.711431][ C0]
[ 63.711431][ C0] other info that might help us debug this:
[ 63.719726][ C0] Possible interrupt unsafe locking scenario:
[ 63.719726][ C0]
[ 63.728931][ C0] CPU0 CPU1
[ 63.734411][ C0] ---- ----
[ 63.740016][ C0] lock(&fiq->waitq);
[ 63.744630][ C0] local_irq_disable();
[ 63.751742][ C0] lock(&(&ctx->ctx_lock)->rlock);
[ 63.759606][ C0] lock(&fiq->waitq);
[ 63.766183][ C0] <Interrupt>
[ 63.769748][ C0] lock(&(&ctx->ctx_lock)->rlock);
[ 63.775109][ C0]
[ 63.775109][ C0] *** DEADLOCK ***
[ 63.775109][ C0]
[ 63.783411][ C0] 2 locks held by swapper/0/0:
[ 63.788341][ C0] #0: ffffffff88fa7e40 (rcu_callback){....}, at: rcu_core+0x60e/0x1560
[ 63.796826][ C0] #1: ffffffff88fa7e80 (rcu_read_lock_sched){....}, at: percpu_ref_switch_to_atomic_rcu+0x20e/0x570
[ 63.807813][ C0]
[ 63.807813][ C0] the shortest dependencies between 2nd lock and 1st lock:
[ 63.817346][ C0] -> (&fiq->waitq){+.+.} {
[ 63.821865][ C0] HARDIRQ-ON-W at:
[ 63.825949][ C0] lock_acquire+0x190/0x410
[ 63.832361][ C0] _raw_spin_lock+0x2f/0x40
[ 63.838785][ C0] flush_bg_queue+0x1f1/0x3b0
[ 63.845267][ C0] fuse_request_queue_background+0x2f8/0x5b0
[ 63.853051][ C0] fuse_request_send_background+0x58/0x110
[ 63.861118][ C0] cuse_channel_open+0x5c3/0x839
[ 63.867976][ C0] misc_open+0x395/0x4c0
[ 63.874718][ C0] chrdev_open+0x245/0x6b0
[ 63.881137][ C0] do_dentry_open+0x4df/0x1250
[ 63.887933][ C0] vfs_open+0xa0/0xd0
[ 63.893736][ C0] path_openat+0x10e9/0x46d0
[ 63.901459][ C0] do_filp_open+0x1a1/0x280
[ 63.908010][ C0] do_sys_open+0x3fe/0x5d0
[ 63.914237][ C0] __x64_sys_openat+0x9d/0x100
[ 63.920807][ C0] do_syscall_64+0xfa/0x760
[ 63.927134][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xbe
[ 63.934841][ C0] SOFTIRQ-ON-W at:
[ 63.939159][ C0] lock_acquire+0x190/0x410
[ 63.945496][ C0] _raw_spin_lock+0x2f/0x40
[ 63.951898][ C0] flush_bg_queue+0x1f1/0x3b0
[ 63.958379][ C0] fuse_request_queue_background+0x2f8/0x5b0
[ 63.966247][ C0] fuse_request_send_background+0x58/0x110
[ 63.973859][ C0] cuse_channel_open+0x5c3/0x839
[ 63.980612][ C0] misc_open+0x395/0x4c0
[ 63.987471][ C0] chrdev_open+0x245/0x6b0
[ 63.993702][ C0] do_dentry_open+0x4df/0x1250
[ 64.000385][ C0] vfs_open+0xa0/0xd0
[ 64.006171][ C0] path_openat+0x10e9/0x46d0
[ 64.012577][ C0] do_filp_open+0x1a1/0x280
[ 64.018885][ C0] do_sys_open+0x3fe/0x5d0
[ 64.025116][ C0] __x64_sys_openat+0x9d/0x100
[ 64.031715][ C0] do_syscall_64+0xfa/0x760
[ 64.038029][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xbe
[ 64.045893][ C0] INITIAL USE at:
[ 64.049949][ C0] lock_acquire+0x190/0x410
[ 64.056191][ C0] _raw_spin_lock+0x2f/0x40
[ 64.062423][ C0] flush_bg_queue+0x1f1/0x3b0
[ 64.068935][ C0] fuse_request_queue_background+0x2f8/0x5b0
[ 64.076682][ C0] fuse_request_send_background+0x58/0x110
[ 64.084217][ C0] cuse_channel_open+0x5c3/0x839
[ 64.091192][ C0] misc_open+0x395/0x4c0
[ 64.097247][ C0] chrdev_open+0x245/0x6b0
[ 64.103468][ C0] do_dentry_open+0x4df/0x1250
[ 64.110037][ C0] vfs_open+0xa0/0xd0
[ 64.115750][ C0] path_openat+0x10e9/0x46d0
[ 64.122085][ C0] do_filp_open+0x1a1/0x280
[ 64.128645][ C0] do_sys_open+0x3fe/0x5d0
[ 64.135037][ C0] __x64_sys_openat+0x9d/0x100
[ 64.141765][ C0] do_syscall_64+0xfa/0x760
[ 64.147987][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xbe
[ 64.155590][ C0] }
[ 64.158422][ C0] ... key at: [<ffffffff8ab91c00>] __key.44810+0x0/0x40
[ 64.165952][ C0] ... acquired at:
[ 64.169830][ C0] _raw_spin_lock+0x2f/0x40
[ 64.174498][ C0] io_submit_one+0xefa/0x2ef0
[ 64.179427][ C0] __x64_sys_io_submit+0x1bd/0x570
[ 64.184696][ C0] do_syscall_64+0xfa/0x760
[ 64.189360][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xbe
[ 64.195431][ C0]
[ 64.197741][ C0] -> (&(&ctx->ctx_lock)->rlock){..-.} {
[ 64.203874][ C0] IN-SOFTIRQ-W at:
[ 64.207854][ C0] lock_acquire+0x190/0x410
[ 64.213986][ C0] _raw_spin_lock_irq+0x60/0x80
[ 64.220557][ C0] free_ioctx_users+0x2d/0x490
[ 64.227204][ C0] percpu_ref_switch_to_atomic_rcu+0x4c0/0x570
[ 64.235167][ C0] rcu_core+0x581/0x1560
[ 64.241189][ C0] rcu_core_si+0x9/0x10
[ 64.246981][ C0] __do_softirq+0x262/0x98c
[ 64.253480][ C0] irq_exit+0x19b/0x1e0
[ 64.259282][ C0] smp_apic_timer_interrupt+0x1a3/0x610
[ 64.266567][ C0] apic_timer_interrupt+0xf/0x20
[ 64.273133][ C0] native_safe_halt+0xe/0x10
[ 64.279349][ C0] default_enter_idle+0x71/0xf0
[ 64.285825][ C0] cpuidle_enter_state+0xef/0xfb0
[ 64.292478][ C0] cpuidle_enter+0x4f/0xa0
[ 64.298681][ C0] do_idle+0x45f/0x6e0
[ 64.304382][ C0] cpu_startup_entry+0x1b/0x20
[ 64.310782][ C0] rest_init+0x245/0x37b
[ 64.316655][ C0] arch_call_rest_init+0xe/0x1b
[ 64.323141][ C0] start_kernel+0x904/0x943
[ 64.329269][ C0] x86_64_start_reservations+0x29/0x2b
[ 64.336593][ C0] x86_64_start_kernel+0x77/0x7b
[ 64.345858][ C0] secondary_startup_64+0xa4/0xb0
[ 64.352596][ C0] INITIAL USE at:
[ 64.357021][ C0] lock_acquire+0x190/0x410
[ 64.363079][ C0] _raw_spin_lock_irq+0x60/0x80
[ 64.369483][ C0] io_submit_one+0xeb5/0x2ef0
[ 64.375702][ C0] __x64_sys_io_submit+0x1bd/0x570
[ 64.382360][ C0] do_syscall_64+0xfa/0x760
[ 64.388405][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xbe
[ 64.395828][ C0] }
[ 64.398353][ C0] ... key at: [<ffffffff8aaf74a0>] __key.54358+0x0/0x40
[ 64.405789][ C0] ... acquired at:
[ 64.409576][ C0] mark_lock+0x517/0x1220
[ 64.414066][ C0] __lock_acquire+0x1e8e/0x4a00
[ 64.419065][ C0] lock_acquire+0x190/0x410
[ 64.423718][ C0] _raw_spin_lock_irq+0x60/0x80
[ 64.428810][ C0] free_ioctx_users+0x2d/0x490
[ 64.433725][ C0] percpu_ref_switch_to_atomic_rcu+0x4c0/0x570
[ 64.440031][ C0] rcu_core+0x581/0x1560
[ 64.444507][ C0] rcu_core_si+0x9/0x10
[ 64.448811][ C0] __do_softirq+0x262/0x98c
[ 64.453460][ C0] irq_exit+0x19b/0x1e0
[ 64.457801][ C0] smp_apic_timer_interrupt+0x1a3/0x610
[ 64.463512][ C0] apic_timer_interrupt+0xf/0x20
[ 64.468684][ C0] native_safe_halt+0xe/0x10
[ 64.473704][ C0] default_enter_idle+0x71/0xf0
[ 64.478705][ C0] cpuidle_enter_state+0xef/0xfb0
[ 64.483887][ C0] cpuidle_enter+0x4f/0xa0
[ 64.488465][ C0] do_idle+0x45f/0x6e0
[ 64.492682][ C0] cpu_startup_entry+0x1b/0x20
[ 64.497593][ C0] rest_init+0x245/0x37b
[ 64.502081][ C0] arch_call_rest_init+0xe/0x1b
[ 64.507080][ C0] start_kernel+0x904/0x943
[ 64.511733][ C0] x86_64_start_reservations+0x29/0x2b
[ 64.517348][ C0] x86_64_start_kernel+0x77/0x7b
[ 64.522452][ C0] secondary_startup_64+0xa4/0xb0
[ 64.527623][ C0]
[ 64.529933][ C0]
[ 64.529933][ C0] stack backtrace:
[ 64.535801][ C0] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.3.0-rc6-next-20190830 #75
[ 64.544271][ C0] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
[ 64.557339][ C0] Call Trace:
[ 64.560597][ C0] <IRQ>
[ 64.563430][ C0] dump_stack+0x172/0x1f0
[ 64.567735][ C0] print_irq_inversion_bug.part.0+0x2e4/0x2f1
[ 64.573781][ C0] check_usage_forwards.cold+0x20/0x29
[ 64.579218][ C0] ? check_usage_backwards+0x330/0x330
[ 64.584756][ C0] ? save_trace+0x3e/0x8c0
[ 64.589180][ C0] mark_lock+0x517/0x1220
[ 64.593576][ C0] ? check_usage_backwards+0x330/0x330
[ 64.599015][ C0] __lock_acquire+0x1e8e/0x4a00
[ 64.603852][ C0] ? __kasan_check_read+0x11/0x20
[ 64.608852][ C0] ? mark_lock+0xc2/0x1220
[ 64.613382][ C0] ? mark_held_locks+0xf0/0xf0
[ 64.618132][ C0] lock_acquire+0x190/0x410
[ 64.622630][ C0] ? free_ioctx_users+0x2d/0x490
[ 64.627636][ C0] _raw_spin_lock_irq+0x60/0x80
[ 64.632471][ C0] ? free_ioctx_users+0x2d/0x490
[ 64.637397][ C0] free_ioctx_users+0x2d/0x490
[ 64.642663][ C0] ? rcu_dynticks_curr_cpu_in_eqs+0x54/0xb0
[ 64.648534][ C0] percpu_ref_switch_to_atomic_rcu+0x4c0/0x570
[ 64.654711][ C0] ? percpu_ref_exit+0xd0/0xd0
[ 64.659547][ C0] rcu_core+0x581/0x1560
[ 64.663764][ C0] ? __rcu_read_unlock+0x6b0/0x6b0
[ 64.668853][ C0] ? rcu_read_lock_sched_held+0x9c/0xd0
[ 64.674445][ C0] ? rcu_read_lock_any_held.part.0+0x50/0x50
[ 64.680397][ C0] ? run_rebalance_domains+0x227/0x2d0
[ 64.685828][ C0] rcu_core_si+0x9/0x10
[ 64.689959][ C0] __do_softirq+0x262/0x98c
[ 64.694441][ C0] ? sched_clock_cpu+0x1b/0x1b0
[ 64.699270][ C0] irq_exit+0x19b/0x1e0
[ 64.703672][ C0] smp_apic_timer_interrupt+0x1a3/0x610
[ 64.709196][ C0] apic_timer_interrupt+0xf/0x20
[ 64.714112][ C0] </IRQ>
[ 64.717129][ C0] RIP: 0010:native_safe_halt+0xe/0x10
[ 64.722482][ C0] Code: 38 c1 69 fa eb 8a 90 90 90 90 90 90 e9 07 00 00 00 0f 00 2d 64 b8 64 00 f4 c3 66 90 e9 07 00 00 00 0f 00 2d 54 b8 64 00 fb f4 <c3> 90 55 48 89 e5 41 57 41 56 41 55 41 54 53 e8 5e a7 1c fa e8 69
[ 64.742087][ C0] RSP: 0018:ffffffff88e07c50 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff13
[ 64.751450][ C0] RAX: 1ffffffff11e5db7 RBX: 0000000000000000 RCX: 0000000000000000
[ 64.759401][ C0] RDX: dffffc0000000000 RSI: 0000000000000006 RDI: ffffffff88e7aa1c
[ 64.767348][ C0] RBP: ffffffff88e07c80 R08: ffffffff88e7a180 R09: 0000000000000000
[ 64.775323][ C0] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000001
[ 64.783286][ C0] R13: 0000000000000000 R14: 0000000000000060 R15: 0000000000000001
[ 64.791265][ C0] ? default_idle+0x4e/0x360
[ 64.795993][ C0] default_enter_idle+0x71/0xf0
[ 64.800842][ C0] cpuidle_enter_state+0xef/0xfb0
[ 64.805866][ C0] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20
[ 64.812105][ C0] cpuidle_enter+0x4f/0xa0
[ 64.816501][ C0] do_idle+0x45f/0x6e0
[ 64.820587][ C0] ? arch_cpu_idle_exit+0x80/0x80
[ 64.825617][ C0] ? trace_hardirqs_on+0x30/0x240
[ 64.830627][ C0] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20
[ 64.836852][ C0] ? debug_smp_processor_id+0x3c/0x214
[ 64.842318][ C0] cpu_startup_entry+0x1b/0x20
[ 64.847062][ C0] rest_init+0x245/0x37b
[ 64.851299][ C0] arch_call_rest_init+0xe/0x1b
[ 64.856300][ C0] start_kernel+0x904/0x943
[ 64.860795][ C0] ? mem_encrypt_init+0xb/0xb
[ 64.865451][ C0] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20
[ 64.871666][ C0] ? x86_family+0x41/0x50
[ 64.875988][ C0] ? __sanitizer_cov_trace_const_cmp1+0x1a/0x20
[ 64.882222][ C0] x86_64_start_reservations+0x29/0x2b
[ 64.887660][ C0] x86_64_start_kernel+0x77/0x7b
[ 64.892577][ C0] secondary_startup_64+0xa4/0xb0