[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[1G[[32m ok [39;49m8[?25h[?0c.
[ 54.659582][ T26] audit: type=1800 audit(1568159153.144:25): pid=8617 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="cron" dev="sda1" ino=2414 res=0
[ 54.681031][ T26] audit: type=1800 audit(1568159153.154:26): pid=8617 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="mcstrans" dev="sda1" ino=2457 res=0
[ 54.731703][ T26] audit: type=1800 audit(1568159153.154:27): pid=8617 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 '10.128.1.48' (ECDSA) to the list of known hosts.
executing program
syzkaller login: [ 62.630349][ C0]
[ 62.632735][ C0] ========================================================
[ 62.639956][ C0] WARNING: possible irq lock inversion dependency detected
[ 62.647142][ C0] 5.3.0-rc6-next-20190830 #75 Not tainted
[ 62.652830][ C0] --------------------------------------------------------
[ 62.660005][ C0] swapper/0/0 just changed the state of lock:
[ 62.666048][ C0] ffff8880a62c1b58 (&(&ctx->ctx_lock)->rlock){..-.}, at: free_ioctx_users+0x2d/0x490
[ 62.675506][ C0] but this lock took another, SOFTIRQ-unsafe lock in the past:
[ 62.683020][ C0] (&fiq->waitq){+.+.}
[ 62.683028][ C0]
[ 62.683028][ C0]
[ 62.683028][ C0] and interrupts could create inverse lock ordering between them.
[ 62.683028][ C0]
[ 62.701688][ C0]
[ 62.701688][ C0] other info that might help us debug this:
[ 62.709724][ C0] Possible interrupt unsafe locking scenario:
[ 62.709724][ C0]
[ 62.718017][ C0] CPU0 CPU1
[ 62.723359][ C0] ---- ----
[ 62.728707][ C0] lock(&fiq->waitq);
[ 62.732762][ C0] local_irq_disable();
[ 62.739490][ C0] lock(&(&ctx->ctx_lock)->rlock);
[ 62.747174][ C0] lock(&fiq->waitq);
[ 62.753731][ C0] <Interrupt>
[ 62.757159][ C0] lock(&(&ctx->ctx_lock)->rlock);
[ 62.762562][ C0]
[ 62.762562][ C0] *** DEADLOCK ***
[ 62.762562][ C0]
[ 62.770699][ C0] 2 locks held by swapper/0/0:
[ 62.775436][ C0] #0: ffffffff88fa7e40 (rcu_callback){....}, at: rcu_core+0x60e/0x1560
[ 62.783766][ C0] #1: ffffffff88fa7e80 (rcu_read_lock_sched){....}, at: percpu_ref_switch_to_atomic_rcu+0x20e/0x570
[ 62.794596][ C0]
[ 62.794596][ C0] the shortest dependencies between 2nd lock and 1st lock:
[ 62.803941][ C0] -> (&fiq->waitq){+.+.} {
[ 62.808432][ C0] HARDIRQ-ON-W at:
[ 62.812597][ C0] lock_acquire+0x190/0x410
[ 62.819167][ C0] _raw_spin_lock+0x2f/0x40
[ 62.825484][ C0] flush_bg_queue+0x1f1/0x3b0
[ 62.832235][ C0] fuse_request_queue_background+0x2f8/0x5b0
[ 62.840031][ C0] fuse_request_send_background+0x58/0x110
[ 62.847698][ C0] cuse_channel_open+0x5c3/0x839
[ 62.854481][ C0] misc_open+0x395/0x4c0
[ 62.860527][ C0] chrdev_open+0x245/0x6b0
[ 62.866767][ C0] do_dentry_open+0x4df/0x1250
[ 62.873351][ C0] vfs_open+0xa0/0xd0
[ 62.879136][ C0] path_openat+0x10e9/0x46d0
[ 62.885535][ C0] do_filp_open+0x1a1/0x280
[ 62.891838][ C0] do_sys_open+0x3fe/0x5d0
[ 62.898057][ C0] __x64_sys_openat+0x9d/0x100
[ 62.904623][ C0] do_syscall_64+0xfa/0x760
[ 62.910926][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xbe
[ 62.918623][ C0] SOFTIRQ-ON-W at:
[ 62.922673][ C0] lock_acquire+0x190/0x410
[ 62.928974][ C0] _raw_spin_lock+0x2f/0x40
[ 62.935275][ C0] flush_bg_queue+0x1f1/0x3b0
[ 62.941763][ C0] fuse_request_queue_background+0x2f8/0x5b0
[ 62.949619][ C0] fuse_request_send_background+0x58/0x110
[ 62.957220][ C0] cuse_channel_open+0x5c3/0x839
[ 62.963956][ C0] misc_open+0x395/0x4c0
[ 62.969994][ C0] chrdev_open+0x245/0x6b0
[ 62.976213][ C0] do_dentry_open+0x4df/0x1250
[ 62.982773][ C0] vfs_open+0xa0/0xd0
[ 62.988559][ C0] path_openat+0x10e9/0x46d0
[ 62.994953][ C0] do_filp_open+0x1a1/0x280
[ 63.001259][ C0] do_sys_open+0x3fe/0x5d0
[ 63.007477][ C0] __x64_sys_openat+0x9d/0x100
[ 63.014048][ C0] do_syscall_64+0xfa/0x760
[ 63.020385][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xbe
[ 63.028071][ C0] INITIAL USE at:
[ 63.032040][ C0] lock_acquire+0x190/0x410
[ 63.038270][ C0] _raw_spin_lock+0x2f/0x40
[ 63.044492][ C0] flush_bg_queue+0x1f1/0x3b0
[ 63.050877][ C0] fuse_request_queue_background+0x2f8/0x5b0
[ 63.058564][ C0] fuse_request_send_background+0x58/0x110
[ 63.066079][ C0] cuse_channel_open+0x5c3/0x839
[ 63.072736][ C0] misc_open+0x395/0x4c0
[ 63.078689][ C0] chrdev_open+0x245/0x6b0
[ 63.084825][ C0] do_dentry_open+0x4df/0x1250
[ 63.091312][ C0] vfs_open+0xa0/0xd0
[ 63.097006][ C0] path_openat+0x10e9/0x46d0
[ 63.103306][ C0] do_filp_open+0x1a1/0x280
[ 63.109527][ C0] do_sys_open+0x3fe/0x5d0
[ 63.115651][ C0] __x64_sys_openat+0x9d/0x100
[ 63.122128][ C0] do_syscall_64+0xfa/0x760
[ 63.128431][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xbe
[ 63.136028][ C0] }
[ 63.138596][ C0] ... key at: [<ffffffff8ab91c00>] __key.44810+0x0/0x40
[ 63.146107][ C0] ... acquired at:
[ 63.149993][ C0] _raw_spin_lock+0x2f/0x40
[ 63.154654][ C0] io_submit_one+0xefa/0x2ef0
[ 63.159476][ C0] __x64_sys_io_submit+0x1bd/0x570
[ 63.164745][ C0] do_syscall_64+0xfa/0x760
[ 63.169406][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xbe
[ 63.175452][ C0]
[ 63.177753][ C0] -> (&(&ctx->ctx_lock)->rlock){..-.} {
[ 63.183273][ C0] IN-SOFTIRQ-W at:
[ 63.187244][ C0] lock_acquire+0x190/0x410
[ 63.193372][ C0] _raw_spin_lock_irq+0x60/0x80
[ 63.199860][ C0] free_ioctx_users+0x2d/0x490
[ 63.206257][ C0] percpu_ref_switch_to_atomic_rcu+0x4c0/0x570
[ 63.214043][ C0] rcu_core+0x581/0x1560
[ 63.219929][ C0] rcu_core_si+0x9/0x10
[ 63.225730][ C0] __do_softirq+0x262/0x98c
[ 63.231860][ C0] irq_exit+0x19b/0x1e0
[ 63.237636][ C0] smp_apic_timer_interrupt+0x1a3/0x610
[ 63.244818][ C0] apic_timer_interrupt+0xf/0x20
[ 63.251387][ C0] native_safe_halt+0xe/0x10
[ 63.257638][ C0] default_enter_idle+0x71/0xf0
[ 63.264126][ C0] cpuidle_enter_state+0xef/0xfb0
[ 63.270778][ C0] cpuidle_enter+0x4f/0xa0
[ 63.276819][ C0] do_idle+0x45f/0x6e0
[ 63.282512][ C0] cpu_startup_entry+0x1b/0x20
[ 63.288902][ C0] rest_init+0x245/0x37b
[ 63.294781][ C0] arch_call_rest_init+0xe/0x1b
[ 63.301261][ C0] start_kernel+0x904/0x943
[ 63.307389][ C0] x86_64_start_reservations+0x29/0x2b
[ 63.314485][ C0] x86_64_start_kernel+0x77/0x7b
[ 63.321067][ C0] secondary_startup_64+0xa4/0xb0
[ 63.327894][ C0] INITIAL USE at:
[ 63.331775][ C0] lock_acquire+0x190/0x410
[ 63.337830][ C0] _raw_spin_lock_irq+0x60/0x80
[ 63.344270][ C0] io_submit_one+0xeb5/0x2ef0
[ 63.350511][ C0] __x64_sys_io_submit+0x1bd/0x570
[ 63.357161][ C0] do_syscall_64+0xfa/0x760
[ 63.363213][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xbe
[ 63.370636][ C0] }
[ 63.373137][ C0] ... key at: [<ffffffff8aaf74a0>] __key.54358+0x0/0x40
[ 63.380558][ C0] ... acquired at:
[ 63.384344][ C0] mark_lock+0x517/0x1220
[ 63.388819][ C0] __lock_acquire+0x1e8e/0x4a00
[ 63.393821][ C0] lock_acquire+0x190/0x410
[ 63.398496][ C0] _raw_spin_lock_irq+0x60/0x80
[ 63.403504][ C0] free_ioctx_users+0x2d/0x490
[ 63.408456][ C0] percpu_ref_switch_to_atomic_rcu+0x4c0/0x570
[ 63.414759][ C0] rcu_core+0x581/0x1560
[ 63.419142][ C0] rcu_core_si+0x9/0x10
[ 63.423443][ C0] __do_softirq+0x262/0x98c
[ 63.428091][ C0] irq_exit+0x19b/0x1e0
[ 63.432390][ C0] smp_apic_timer_interrupt+0x1a3/0x610
[ 63.438076][ C0] apic_timer_interrupt+0xf/0x20
[ 63.443158][ C0] native_safe_halt+0xe/0x10
[ 63.447903][ C0] default_enter_idle+0x71/0xf0
[ 63.452901][ C0] cpuidle_enter_state+0xef/0xfb0
[ 63.458069][ C0] cpuidle_enter+0x4f/0xa0
[ 63.462633][ C0] do_idle+0x45f/0x6e0
[ 63.466846][ C0] cpu_startup_entry+0x1b/0x20
[ 63.471755][ C0] rest_init+0x245/0x37b
[ 63.476144][ C0] arch_call_rest_init+0xe/0x1b
[ 63.481141][ C0] start_kernel+0x904/0x943
[ 63.485876][ C0] x86_64_start_reservations+0x29/0x2b
[ 63.491480][ C0] x86_64_start_kernel+0x77/0x7b
[ 63.496563][ C0] secondary_startup_64+0xa4/0xb0
[ 63.501728][ C0]
[ 63.504029][ C0]
[ 63.504029][ C0] stack backtrace:
[ 63.509915][ C0] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.3.0-rc6-next-20190830 #75
[ 63.518300][ C0] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
[ 63.528328][ C0] Call Trace:
[ 63.531586][ C0] <IRQ>
[ 63.534416][ C0] dump_stack+0x172/0x1f0
[ 63.538721][ C0] print_irq_inversion_bug.part.0+0x2e4/0x2f1
[ 63.544764][ C0] check_usage_forwards.cold+0x20/0x29
[ 63.550206][ C0] ? check_usage_backwards+0x330/0x330
[ 63.555637][ C0] ? save_trace+0x3e/0x8c0
[ 63.560040][ C0] mark_lock+0x517/0x1220
[ 63.564343][ C0] ? check_usage_backwards+0x330/0x330
[ 63.569785][ C0] __lock_acquire+0x1e8e/0x4a00
[ 63.574618][ C0] ? __kasan_check_read+0x11/0x20
[ 63.579615][ C0] ? mark_lock+0xc2/0x1220
[ 63.584015][ C0] ? mark_held_locks+0xf0/0xf0
[ 63.588753][ C0] lock_acquire+0x190/0x410
[ 63.593229][ C0] ? free_ioctx_users+0x2d/0x490
[ 63.598147][ C0] _raw_spin_lock_irq+0x60/0x80
[ 63.603008][ C0] ? free_ioctx_users+0x2d/0x490
[ 63.607916][ C0] free_ioctx_users+0x2d/0x490
[ 63.612652][ C0] ? rcu_dynticks_curr_cpu_in_eqs+0x54/0xb0
[ 63.618518][ C0] percpu_ref_switch_to_atomic_rcu+0x4c0/0x570
[ 63.624651][ C0] ? percpu_ref_exit+0xd0/0xd0
[ 63.629386][ C0] rcu_core+0x581/0x1560
[ 63.633603][ C0] ? __rcu_read_unlock+0x6b0/0x6b0
[ 63.638689][ C0] ? rcu_read_lock_sched_held+0x9c/0xd0
[ 63.644206][ C0] ? rcu_read_lock_any_held.part.0+0x50/0x50
[ 63.650157][ C0] ? run_rebalance_domains+0x227/0x2d0
[ 63.655587][ C0] rcu_core_si+0x9/0x10
[ 63.659719][ C0] __do_softirq+0x262/0x98c
[ 63.664205][ C0] ? sched_clock_cpu+0x1b/0x1b0
[ 63.669030][ C0] irq_exit+0x19b/0x1e0
[ 63.673158][ C0] smp_apic_timer_interrupt+0x1a3/0x610
[ 63.678674][ C0] apic_timer_interrupt+0xf/0x20
[ 63.683593][ C0] </IRQ>
[ 63.686520][ C0] RIP: 0010:native_safe_halt+0xe/0x10
[ 63.691869][ 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
[ 63.711455][ C0] RSP: 0018:ffffffff88e07c50 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff13
[ 63.719844][ C0] RAX: 1ffffffff11e5db7 RBX: 0000000000000000 RCX: 0000000000000000
[ 63.727812][ C0] RDX: dffffc0000000000 RSI: 0000000000000006 RDI: ffffffff88e7aa1c
[ 63.735768][ C0] RBP: ffffffff88e07c80 R08: ffffffff88e7a180 R09: 0000000000000000
[ 63.743714][ C0] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000001
[ 63.751664][ C0] R13: 0000000000000000 R14: 0000000000000060 R15: 0000000000000001
[ 63.759635][ C0] ? default_idle+0x4e/0x360
[ 63.764201][ C0] default_enter_idle+0x71/0xf0
[ 63.769026][ C0] cpuidle_enter_state+0xef/0xfb0
[ 63.774025][ C0] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20
[ 63.780245][ C0] cpuidle_enter+0x4f/0xa0
[ 63.784643][ C0] do_idle+0x45f/0x6e0
[ 63.788686][ C0] ? arch_cpu_idle_exit+0x80/0x80
[ 63.793682][ C0] ? do_idle+0x387/0x6e0
[ 63.797899][ C0] cpu_startup_entry+0x1b/0x20
[ 63.802636][ C0] rest_init+0x245/0x37b
[ 63.806857][ C0] arch_call_rest_init+0xe/0x1b
[ 63.811689][ C0] start_kernel+0x904/0x943
[ 63.816175][ C0] ? mem_encrypt_init+0xb/0xb
[ 63.820827][ C0] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20
[ 63.827039][ C0] ? x86_family+0x41/0x50
[ 63.831343][ C0] ? __sanitizer_cov_trace_c