[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[1G[[32m ok [39;49m8[?25h[?0c.
[ 55.382142][ T26] audit: type=1800 audit(1567341736.399:25): pid=8465 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="cron" dev="sda1" ino=2414 res=0
[ 55.417556][ T26] audit: type=1800 audit(1567341736.399:26): pid=8465 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="mcstrans" dev="sda1" ino=2457 res=0
[ 55.474811][ T26] audit: type=1800 audit(1567341736.409:27): pid=8465 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 '10.128.0.142' (ECDSA) to the list of known hosts.
executing program
syzkaller login: [ 63.277617][ C0]
[ 63.279970][ C0] ========================================================
[ 63.287158][ C0] WARNING: possible irq lock inversion dependency detected
[ 63.294343][ C0] 5.3.0-rc6-next-20190830 #75 Not tainted
[ 63.300039][ C0] --------------------------------------------------------
[ 63.307204][ C0] swapper/0/0 just changed the state of lock:
[ 63.313239][ C0] ffff88809481bb58 (&(&ctx->ctx_lock)->rlock){..-.}, at: free_ioctx_users+0x2d/0x490
[ 63.322674][ C0] but this lock took another, SOFTIRQ-unsafe lock in the past:
[ 63.330182][ C0] (&fiq->waitq){+.+.}
[ 63.330188][ C0]
[ 63.330188][ C0]
[ 63.330188][ C0] and interrupts could create inverse lock ordering between them.
[ 63.330188][ C0]
[ 63.348497][ C0]
[ 63.348497][ C0] other info that might help us debug this:
[ 63.356525][ C0] Possible interrupt unsafe locking scenario:
[ 63.356525][ C0]
[ 63.364810][ C0] CPU0 CPU1
[ 63.370145][ C0] ---- ----
[ 63.375493][ C0] lock(&fiq->waitq);
[ 63.379526][ C0] local_irq_disable();
[ 63.386249][ C0] lock(&(&ctx->ctx_lock)->rlock);
[ 63.393930][ C0] lock(&fiq->waitq);
[ 63.400484][ C0] <Interrupt>
[ 63.403915][ C0] lock(&(&ctx->ctx_lock)->rlock);
[ 63.409253][ C0]
[ 63.409253][ C0] *** DEADLOCK ***
[ 63.409253][ C0]
[ 63.417381][ C0] 2 locks held by swapper/0/0:
[ 63.424245][ C0] #0: ffffffff88fa7e40 (rcu_callback){....}, at: rcu_core+0x60e/0x1560
[ 63.432559][ C0] #1: ffffffff88fa7e80 (rcu_read_lock_sched){....}, at: percpu_ref_switch_to_atomic_rcu+0x20e/0x570
[ 63.443382][ C0]
[ 63.443382][ C0] the shortest dependencies between 2nd lock and 1st lock:
[ 63.452736][ C0] -> (&fiq->waitq){+.+.} {
[ 63.457209][ C0] HARDIRQ-ON-W at:
[ 63.461253][ C0] lock_acquire+0x190/0x410
[ 63.467553][ C0] _raw_spin_lock+0x2f/0x40
[ 63.473866][ C0] flush_bg_queue+0x1f1/0x3b0
[ 63.480339][ C0] fuse_request_queue_background+0x2f8/0x5b0
[ 63.488113][ C0] fuse_request_send_background+0x58/0x110
[ 63.495711][ C0] cuse_channel_open+0x5c3/0x839
[ 63.502458][ C0] misc_open+0x395/0x4c0
[ 63.508501][ C0] chrdev_open+0x245/0x6b0
[ 63.514709][ C0] do_dentry_open+0x4df/0x1250
[ 63.521278][ C0] vfs_open+0xa0/0xd0
[ 63.527065][ C0] path_openat+0x10e9/0x46d0
[ 63.533449][ C0] do_filp_open+0x1a1/0x280
[ 63.539747][ C0] do_sys_open+0x3fe/0x5d0
[ 63.545967][ C0] __x64_sys_openat+0x9d/0x100
[ 63.552527][ C0] do_syscall_64+0xfa/0x760
[ 63.558823][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xbe
[ 63.566502][ C0] SOFTIRQ-ON-W at:
[ 63.570546][ C0] lock_acquire+0x190/0x410
[ 63.576841][ C0] _raw_spin_lock+0x2f/0x40
[ 63.583133][ C0] flush_bg_queue+0x1f1/0x3b0
[ 63.589618][ C0] fuse_request_queue_background+0x2f8/0x5b0
[ 63.597404][ C0] fuse_request_send_background+0x58/0x110
[ 63.605002][ C0] cuse_channel_open+0x5c3/0x839
[ 63.611731][ C0] misc_open+0x395/0x4c0
[ 63.617771][ C0] chrdev_open+0x245/0x6b0
[ 63.623994][ C0] do_dentry_open+0x4df/0x1250
[ 63.630552][ C0] vfs_open+0xa0/0xd0
[ 63.636327][ C0] path_openat+0x10e9/0x46d0
[ 63.642724][ C0] do_filp_open+0x1a1/0x280
[ 63.649023][ C0] do_sys_open+0x3fe/0x5d0
[ 63.655232][ C0] __x64_sys_openat+0x9d/0x100
[ 63.661788][ C0] do_syscall_64+0xfa/0x760
[ 63.668085][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xbe
[ 63.675763][ C0] INITIAL USE at:
[ 63.679716][ C0] lock_acquire+0x190/0x410
[ 63.685926][ C0] _raw_spin_lock+0x2f/0x40
[ 63.692157][ C0] flush_bg_queue+0x1f1/0x3b0
[ 63.698545][ C0] fuse_request_queue_background+0x2f8/0x5b0
[ 63.706242][ C0] fuse_request_send_background+0x58/0x110
[ 63.713751][ C0] cuse_channel_open+0x5c3/0x839
[ 63.720407][ C0] misc_open+0x395/0x4c0
[ 63.726368][ C0] chrdev_open+0x245/0x6b0
[ 63.732491][ C0] do_dentry_open+0x4df/0x1250
[ 63.738959][ C0] vfs_open+0xa0/0xd0
[ 63.744659][ C0] path_openat+0x10e9/0x46d0
[ 63.750956][ C0] do_filp_open+0x1a1/0x280
[ 63.757163][ C0] do_sys_open+0x3fe/0x5d0
[ 63.763289][ C0] __x64_sys_openat+0x9d/0x100
[ 63.769758][ C0] do_syscall_64+0xfa/0x760
[ 63.775970][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xbe
[ 63.783560][ C0] }
[ 63.786124][ C0] ... key at: [<ffffffff8ab91c00>] __key.44810+0x0/0x40
[ 63.793629][ C0] ... acquired at:
[ 63.797514][ C0] _raw_spin_lock+0x2f/0x40
[ 63.802164][ C0] io_submit_one+0xefa/0x2ef0
[ 63.806982][ C0] __x64_sys_io_submit+0x1bd/0x570
[ 63.812247][ C0] do_syscall_64+0xfa/0x760
[ 63.816894][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xbe
[ 63.822949][ C0]
[ 63.825271][ C0] -> (&(&ctx->ctx_lock)->rlock){..-.} {
[ 63.830788][ C0] IN-SOFTIRQ-W at:
[ 63.834743][ C0] lock_acquire+0x190/0x410
[ 63.840863][ C0] _raw_spin_lock_irq+0x60/0x80
[ 63.847330][ C0] free_ioctx_users+0x2d/0x490
[ 63.853721][ C0] percpu_ref_switch_to_atomic_rcu+0x4c0/0x570
[ 63.861492][ C0] rcu_core+0x581/0x1560
[ 63.867354][ C0] rcu_core_si+0x9/0x10
[ 63.873129][ C0] __do_softirq+0x262/0x98c
[ 63.879249][ C0] irq_exit+0x19b/0x1e0
[ 63.885021][ C0] smp_apic_timer_interrupt+0x1a3/0x610
[ 63.892187][ C0] apic_timer_interrupt+0xf/0x20
[ 63.898744][ C0] native_safe_halt+0xe/0x10
[ 63.904965][ C0] default_enter_idle+0x71/0xf0
[ 63.911440][ C0] cpuidle_enter_state+0xef/0xfb0
[ 63.918081][ C0] cpuidle_enter+0x4f/0xa0
[ 63.924115][ C0] do_idle+0x45f/0x6e0
[ 63.929802][ C0] cpu_startup_entry+0x1b/0x20
[ 63.936183][ C0] rest_init+0x245/0x37b
[ 63.942050][ C0] arch_call_rest_init+0xe/0x1b
[ 63.948522][ C0] start_kernel+0x904/0x943
[ 63.954644][ C0] x86_64_start_reservations+0x29/0x2b
[ 63.961736][ C0] x86_64_start_kernel+0x77/0x7b
[ 63.968296][ C0] secondary_startup_64+0xa4/0xb0
[ 63.974937][ C0] INITIAL USE at:
[ 63.978805][ C0] lock_acquire+0x190/0x410
[ 63.984842][ C0] _raw_spin_lock_irq+0x60/0x80
[ 63.991241][ C0] io_submit_one+0xeb5/0x2ef0
[ 63.997469][ C0] __x64_sys_io_submit+0x1bd/0x570
[ 64.004113][ C0] do_syscall_64+0xfa/0x760
[ 64.010152][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xbe
[ 64.017573][ C0] }
[ 64.020066][ C0] ... key at: [<ffffffff8aaf74a0>] __key.54358+0x0/0x40
[ 64.027486][ C0] ... acquired at:
[ 64.031271][ C0] mark_lock+0x517/0x1220
[ 64.035745][ C0] __lock_acquire+0x1e8e/0x4a00
[ 64.040738][ C0] lock_acquire+0x190/0x410
[ 64.045384][ C0] _raw_spin_lock_irq+0x60/0x80
[ 64.050381][ C0] free_ioctx_users+0x2d/0x490
[ 64.055287][ C0] percpu_ref_switch_to_atomic_rcu+0x4c0/0x570
[ 64.061592][ C0] rcu_core+0x581/0x1560
[ 64.065977][ C0] rcu_core_si+0x9/0x10
[ 64.070280][ C0] __do_softirq+0x262/0x98c
[ 64.074930][ C0] irq_exit+0x19b/0x1e0
[ 64.079228][ C0] smp_apic_timer_interrupt+0x1a3/0x610
[ 64.084913][ C0] apic_timer_interrupt+0xf/0x20
[ 64.089992][ C0] native_safe_halt+0xe/0x10
[ 64.094729][ C0] default_enter_idle+0x71/0xf0
[ 64.099724][ C0] cpuidle_enter_state+0xef/0xfb0
[ 64.104889][ C0] cpuidle_enter+0x4f/0xa0
[ 64.109450][ C0] do_idle+0x45f/0x6e0
[ 64.113659][ C0] cpu_startup_entry+0x1b/0x20
[ 64.118565][ C0] rest_init+0x245/0x37b
[ 64.122952][ C0] arch_call_rest_init+0xe/0x1b
[ 64.127955][ C0] start_kernel+0x904/0x943
[ 64.132611][ C0] x86_64_start_reservations+0x29/0x2b
[ 64.138214][ C0] x86_64_start_kernel+0x77/0x7b
[ 64.143292][ C0] secondary_startup_64+0xa4/0xb0
[ 64.148456][ C0]
[ 64.150760][ C0]
[ 64.150760][ C0] stack backtrace:
[ 64.156628][ C0] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.3.0-rc6-next-20190830 #75
[ 64.164916][ C0] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
[ 64.174959][ C0] Call Trace:
[ 64.178216][ C0] <IRQ>
[ 64.181045][ C0] dump_stack+0x172/0x1f0
[ 64.185349][ C0] print_irq_inversion_bug.part.0+0x2e4/0x2f1
[ 64.191386][ C0] check_usage_forwards.cold+0x20/0x29
[ 64.196816][ C0] ? check_usage_backwards+0x330/0x330
[ 64.202245][ C0] ? save_trace+0x3e/0x8c0
[ 64.206718][ C0] mark_lock+0x517/0x1220
[ 64.211018][ C0] ? check_usage_backwards+0x330/0x330
[ 64.216446][ C0] __lock_acquire+0x1e8e/0x4a00
[ 64.221270][ C0] ? __kasan_check_read+0x11/0x20
[ 64.226264][ C0] ? mark_lock+0xc2/0x1220
[ 64.230653][ C0] ? mark_held_locks+0xf0/0xf0
[ 64.235404][ C0] lock_acquire+0x190/0x410
[ 64.239876][ C0] ? free_ioctx_users+0x2d/0x490
[ 64.244787][ C0] _raw_spin_lock_irq+0x60/0x80
[ 64.249611][ C0] ? free_ioctx_users+0x2d/0x490
[ 64.255852][ C0] free_ioctx_users+0x2d/0x490
[ 64.260588][ C0] ? rcu_dynticks_curr_cpu_in_eqs+0x54/0xb0
[ 64.266453][ C0] percpu_ref_switch_to_atomic_rcu+0x4c0/0x570
[ 64.272590][ C0] ? percpu_ref_exit+0xd0/0xd0
[ 64.277325][ C0] rcu_core+0x581/0x1560
[ 64.281537][ C0] ? __rcu_read_unlock+0x6b0/0x6b0
[ 64.286627][ C0] ? rcu_read_lock_sched_held+0x9c/0xd0
[ 64.292159][ C0] ? rcu_read_lock_any_held.part.0+0x50/0x50
[ 64.298121][ C0] ? run_rebalance_domains+0x227/0x2d0
[ 64.303549][ C0] rcu_core_si+0x9/0x10
[ 64.307692][ C0] __do_softirq+0x262/0x98c
[ 64.312176][ C0] ? sched_clock_cpu+0x1b/0x1b0
[ 64.317013][ C0] irq_exit+0x19b/0x1e0
[ 64.321137][ C0] smp_apic_timer_interrupt+0x1a3/0x610
[ 64.326656][ C0] apic_timer_interrupt+0xf/0x20
[ 64.331562][ C0] </IRQ>
[ 64.334476][ C0] RIP: 0010:native_safe_halt+0xe/0x10
[ 64.339991][ 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
[ 64.359743][ C0] RSP: 0018:ffffffff88e07c50 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff13
[ 64.368128][ C0] RAX: 1ffffffff11e5db7 RBX: 0000000000000000 RCX: 0000000000000000
[ 64.376075][ C0] RDX: dffffc0000000000 RSI: 0000000000000006 RDI: ffffffff88e7aa1c
[ 64.384017][ C0] RBP: ffffffff88e07c80 R08: ffffffff88e7a180 R09: 0000000000000000
[ 64.391973][ C0] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000001
[ 64.399917][ C0] R13: 0000000000000000 R14: 0000000000000060 R15: 0000000000000001
[ 64.407890][ C0] ? default_idle+0x4e/0x360
[ 64.412473][ C0] default_enter_idle+0x71/0xf0
[ 64.417295][ C0] cpuidle_enter_state+0xef/0xfb0
[ 64.422293][ C0] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20
[ 64.428506][ C0] cpuidle_enter+0x4f/0xa0
[ 64.432909][ C0] do_idle+0x45f/0x6e0
[ 64.436950][ C0] ? arch_cpu_idle_exit+0x80/0x80
[ 64.441944][ C0] ? trace_hardirqs_on+0x30/0x240
[ 64.446940][ C0] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20
[ 64.453179][ C0] ? debug_smp_processor_id+0x3c/0x214
[ 64.458611][ C0] cpu_startup_entry+0x1b/0x20
[ 64.463343][ C0] rest_init+0x245/0x37b
[ 64.467606][ C0] arch_call_rest_init+0xe/0x1b
[ 64.472429][ C0] start_kernel+0x904/0x943
[ 64.476905][ C0] ? mem_encrypt_init+0xb/0xb
[ 64.481554]