[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[1G[[32m ok [39;49m8[?25h[?0c.
[ 52.506810][ T26] audit: type=1800 audit(1567478123.140:25): pid=8453 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="cron" dev="sda1" ino=2414 res=0
[ 52.527308][ T26] audit: type=1800 audit(1567478123.160:26): pid=8453 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="mcstrans" dev="sda1" ino=2457 res=0
[ 52.575662][ T26] audit: type=1800 audit(1567478123.160:27): pid=8453 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 '10.128.1.34' (ECDSA) to the list of known hosts.
executing program
syzkaller login: [ 64.036161][ C0]
[ 64.038526][ C0] ========================================================
[ 64.045687][ C0] WARNING: possible irq lock inversion dependency detected
[ 64.052972][ C0] 5.3.0-rc6-next-20190830 #75 Not tainted
[ 64.058744][ C0] --------------------------------------------------------
[ 64.065906][ C0] swapper/0/0 just changed the state of lock:
[ 64.071973][ C0] ffff88809f94fb58 (&(&ctx->ctx_lock)->rlock){..-.}, at: free_ioctx_users+0x2d/0x490
[ 64.081407][ C0] but this lock took another, SOFTIRQ-unsafe lock in the past:
[ 64.088996][ C0] (&fiq->waitq){+.+.}
[ 64.089001][ C0]
[ 64.089001][ C0]
[ 64.089001][ C0] and interrupts could create inverse lock ordering between them.
[ 64.089001][ C0]
[ 64.107305][ C0]
[ 64.107305][ C0] other info that might help us debug this:
[ 64.115330][ C0] Possible interrupt unsafe locking scenario:
[ 64.115330][ C0]
[ 64.123613][ C0] CPU0 CPU1
[ 64.128947][ C0] ---- ----
[ 64.134286][ C0] lock(&fiq->waitq);
[ 64.138321][ C0] local_irq_disable();
[ 64.145046][ C0] lock(&(&ctx->ctx_lock)->rlock);
[ 64.152727][ C0] lock(&fiq->waitq);
[ 64.159287][ C0] <Interrupt>
[ 64.162709][ C0] lock(&(&ctx->ctx_lock)->rlock);
[ 64.168043][ C0]
[ 64.168043][ C0] *** DEADLOCK ***
[ 64.168043][ C0]
[ 64.176266][ C0] 2 locks held by swapper/0/0:
[ 64.180992][ C0] #0: ffffffff88fa7e40 (rcu_callback){....}, at: rcu_core+0x60e/0x1560
[ 64.189420][ C0] #1: ffffffff88fa7e80 (rcu_read_lock_sched){....}, at: percpu_ref_switch_to_atomic_rcu+0x20e/0x570
[ 64.200295][ C0]
[ 64.200295][ C0] the shortest dependencies between 2nd lock and 1st lock:
[ 64.209651][ C0] -> (&fiq->waitq){+.+.} {
[ 64.214136][ C0] HARDIRQ-ON-W at:
[ 64.218183][ C0] lock_acquire+0x190/0x410
[ 64.224480][ C0] _raw_spin_lock+0x2f/0x40
[ 64.230774][ C0] flush_bg_queue+0x1f1/0x3b0
[ 64.237242][ C0] fuse_request_queue_background+0x2f8/0x5b0
[ 64.245011][ C0] fuse_request_send_background+0x58/0x110
[ 64.252607][ C0] cuse_channel_open+0x5c3/0x839
[ 64.259337][ C0] misc_open+0x395/0x4c0
[ 64.265374][ C0] chrdev_open+0x245/0x6b0
[ 64.271584][ C0] do_dentry_open+0x4df/0x1250
[ 64.278142][ C0] vfs_open+0xa0/0xd0
[ 64.283917][ C0] path_openat+0x10e9/0x46d0
[ 64.290298][ C0] do_filp_open+0x1a1/0x280
[ 64.296594][ C0] do_sys_open+0x3fe/0x5d0
[ 64.302802][ C0] __x64_sys_openat+0x9d/0x100
[ 64.309357][ C0] do_syscall_64+0xfa/0x760
[ 64.315650][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xbe
[ 64.323338][ C0] SOFTIRQ-ON-W at:
[ 64.327391][ C0] lock_acquire+0x190/0x410
[ 64.333683][ C0] _raw_spin_lock+0x2f/0x40
[ 64.339977][ C0] flush_bg_queue+0x1f1/0x3b0
[ 64.346443][ C0] fuse_request_queue_background+0x2f8/0x5b0
[ 64.354214][ C0] fuse_request_send_background+0x58/0x110
[ 64.361819][ C0] cuse_channel_open+0x5c3/0x839
[ 64.368565][ C0] misc_open+0x395/0x4c0
[ 64.374618][ C0] chrdev_open+0x245/0x6b0
[ 64.380829][ C0] do_dentry_open+0x4df/0x1250
[ 64.387384][ C0] vfs_open+0xa0/0xd0
[ 64.393158][ C0] path_openat+0x10e9/0x46d0
[ 64.399538][ C0] do_filp_open+0x1a1/0x280
[ 64.405831][ C0] do_sys_open+0x3fe/0x5d0
[ 64.412043][ C0] __x64_sys_openat+0x9d/0x100
[ 64.418600][ C0] do_syscall_64+0xfa/0x760
[ 64.424893][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xbe
[ 64.432570][ C0] INITIAL USE at:
[ 64.436520][ C0] lock_acquire+0x190/0x410
[ 64.442730][ C0] _raw_spin_lock+0x2f/0x40
[ 64.448933][ C0] flush_bg_queue+0x1f1/0x3b0
[ 64.455313][ C0] fuse_request_queue_background+0x2f8/0x5b0
[ 64.462991][ C0] fuse_request_send_background+0x58/0x110
[ 64.470496][ C0] cuse_channel_open+0x5c3/0x839
[ 64.477136][ C0] misc_open+0x395/0x4c0
[ 64.483086][ C0] chrdev_open+0x245/0x6b0
[ 64.489219][ C0] do_dentry_open+0x4df/0x1250
[ 64.495687][ C0] vfs_open+0xa0/0xd0
[ 64.501372][ C0] path_openat+0x10e9/0x46d0
[ 64.507680][ C0] do_filp_open+0x1a1/0x280
[ 64.513887][ C0] do_sys_open+0x3fe/0x5d0
[ 64.520031][ C0] __x64_sys_openat+0x9d/0x100
[ 64.526499][ C0] do_syscall_64+0xfa/0x760
[ 64.532705][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xbe
[ 64.540299][ C0] }
[ 64.542861][ C0] ... key at: [<ffffffff8ab91c00>] __key.44810+0x0/0x40
[ 64.550376][ C0] ... acquired at:
[ 64.554240][ C0] _raw_spin_lock+0x2f/0x40
[ 64.558899][ C0] io_submit_one+0xefa/0x2ef0
[ 64.563716][ C0] __x64_sys_io_submit+0x1bd/0x570
[ 64.568973][ C0] do_syscall_64+0xfa/0x760
[ 64.573617][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xbe
[ 64.579647][ C0]
[ 64.581945][ C0] -> (&(&ctx->ctx_lock)->rlock){..-.} {
[ 64.587460][ C0] IN-SOFTIRQ-W at:
[ 64.591432][ C0] lock_acquire+0x190/0x410
[ 64.597677][ C0] _raw_spin_lock_irq+0x60/0x80
[ 64.604153][ C0] free_ioctx_users+0x2d/0x490
[ 64.610534][ C0] percpu_ref_switch_to_atomic_rcu+0x4c0/0x570
[ 64.618304][ C0] rcu_core+0x581/0x1560
[ 64.624176][ C0] rcu_core_si+0x9/0x10
[ 64.629950][ C0] __do_softirq+0x262/0x98c
[ 64.636071][ C0] irq_exit+0x19b/0x1e0
[ 64.641841][ C0] smp_apic_timer_interrupt+0x1a3/0x610
[ 64.648999][ C0] apic_timer_interrupt+0xf/0x20
[ 64.655553][ C0] native_safe_halt+0xe/0x10
[ 64.661943][ C0] default_enter_idle+0x71/0xf0
[ 64.668412][ C0] cpuidle_enter_state+0xef/0xfb0
[ 64.675080][ C0] cpuidle_enter+0x4f/0xa0
[ 64.681120][ C0] do_idle+0x45f/0x6e0
[ 64.686824][ C0] cpu_startup_entry+0x1b/0x20
[ 64.693208][ C0] rest_init+0x245/0x37b
[ 64.699070][ C0] arch_call_rest_init+0xe/0x1b
[ 64.705542][ C0] start_kernel+0x904/0x943
[ 64.711669][ C0] x86_64_start_reservations+0x29/0x2b
[ 64.718764][ C0] x86_64_start_kernel+0x77/0x7b
[ 64.725324][ C0] secondary_startup_64+0xa4/0xb0
[ 64.731968][ C0] INITIAL USE at:
[ 64.735839][ C0] lock_acquire+0x190/0x410
[ 64.741904][ C0] _raw_spin_lock_irq+0x60/0x80
[ 64.748315][ C0] io_submit_one+0xeb5/0x2ef0
[ 64.754522][ C0] __x64_sys_io_submit+0x1bd/0x570
[ 64.761163][ C0] do_syscall_64+0xfa/0x760
[ 64.767205][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xbe
[ 64.774623][ C0] }
[ 64.777231][ C0] ... key at: [<ffffffff8aaf74a0>] __key.54358+0x0/0x40
[ 64.784649][ C0] ... acquired at:
[ 64.788429][ C0] mark_lock+0x517/0x1220
[ 64.792901][ C0] __lock_acquire+0x1e8e/0x4a00
[ 64.797902][ C0] lock_acquire+0x190/0x410
[ 64.802636][ C0] _raw_spin_lock_irq+0x60/0x80
[ 64.807631][ C0] free_ioctx_users+0x2d/0x490
[ 64.812553][ C0] percpu_ref_switch_to_atomic_rcu+0x4c0/0x570
[ 64.818873][ C0] rcu_core+0x581/0x1560
[ 64.823256][ C0] rcu_core_si+0x9/0x10
[ 64.827552][ C0] __do_softirq+0x262/0x98c
[ 64.832198][ C0] irq_exit+0x19b/0x1e0
[ 64.836505][ C0] smp_apic_timer_interrupt+0x1a3/0x610
[ 64.842187][ C0] apic_timer_interrupt+0xf/0x20
[ 64.847266][ C0] native_safe_halt+0xe/0x10
[ 64.852009][ C0] default_enter_idle+0x71/0xf0
[ 64.857002][ C0] cpuidle_enter_state+0xef/0xfb0
[ 64.862175][ C0] cpuidle_enter+0x4f/0xa0
[ 64.866735][ C0] do_idle+0x45f/0x6e0
[ 64.870945][ C0] cpu_startup_entry+0x1b/0x20
[ 64.875851][ C0] rest_init+0x245/0x37b
[ 64.880235][ C0] arch_call_rest_init+0xe/0x1b
[ 64.885255][ C0] start_kernel+0x904/0x943
[ 64.889899][ C0] x86_64_start_reservations+0x29/0x2b
[ 64.895500][ C0] x86_64_start_kernel+0x77/0x7b
[ 64.900605][ C0] secondary_startup_64+0xa4/0xb0
[ 64.905863][ C0]
[ 64.908160][ C0]
[ 64.908160][ C0] stack backtrace:
[ 64.914023][ C0] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.3.0-rc6-next-20190830 #75
[ 64.922307][ C0] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
[ 64.932331][ C0] Call Trace:
[ 64.935584][ C0] <IRQ>
[ 64.938411][ C0] dump_stack+0x172/0x1f0
[ 64.942715][ C0] print_irq_inversion_bug.part.0+0x2e4/0x2f1
[ 64.948755][ C0] check_usage_forwards.cold+0x20/0x29
[ 64.954189][ C0] ? check_usage_backwards+0x330/0x330
[ 64.959628][ C0] ? save_trace+0x3e/0x8c0
[ 64.964043][ C0] mark_lock+0x517/0x1220
[ 64.968340][ C0] ? check_usage_backwards+0x330/0x330
[ 64.973772][ C0] __lock_acquire+0x1e8e/0x4a00
[ 64.978591][ C0] ? __kasan_check_read+0x11/0x20
[ 64.983603][ C0] ? mark_lock+0xc2/0x1220
[ 64.987990][ C0] ? mark_held_locks+0xf0/0xf0
[ 64.992721][ C0] lock_acquire+0x190/0x410
[ 64.997202][ C0] ? free_ioctx_users+0x2d/0x490
[ 65.002108][ C0] _raw_spin_lock_irq+0x60/0x80
[ 65.006925][ C0] ? free_ioctx_users+0x2d/0x490
[ 65.011826][ C0] free_ioctx_users+0x2d/0x490
[ 65.016556][ C0] ? rcu_dynticks_curr_cpu_in_eqs+0x54/0xb0
[ 65.022415][ C0] percpu_ref_switch_to_atomic_rcu+0x4c0/0x570
[ 65.028560][ C0] ? percpu_ref_exit+0xd0/0xd0
[ 65.033286][ C0] rcu_core+0x581/0x1560
[ 65.037498][ C0] ? __rcu_read_unlock+0x6b0/0x6b0
[ 65.042667][ C0] ? rcu_read_lock_sched_held+0x9c/0xd0
[ 65.048184][ C0] ? rcu_read_lock_any_held.part.0+0x50/0x50
[ 65.054130][ C0] ? run_rebalance_domains+0x227/0x2d0
[ 65.059563][ C0] rcu_core_si+0x9/0x10
[ 65.063689][ C0] __do_softirq+0x262/0x98c
[ 65.068167][ C0] ? sched_clock_cpu+0x1b/0x1b0
[ 65.072989][ C0] irq_exit+0x19b/0x1e0
[ 65.077131][ C0] smp_apic_timer_interrupt+0x1a3/0x610
[ 65.082644][ C0] apic_timer_interrupt+0xf/0x20
[ 65.087543][ C0] </IRQ>
[ 65.090451][ C0] RIP: 0010:native_safe_halt+0xe/0x10
[ 65.095790][ 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
[ 65.115367][ C0] RSP: 0018:ffffffff88e07c50 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff13
[ 65.123744][ C0] RAX: 1ffffffff11e5db7 RBX: 0000000000000000 RCX: 0000000000000000
[ 65.131703][ C0] RDX: dffffc0000000000 RSI: 0000000000000006 RDI: ffffffff88e7aa1c
[ 65.139647][ C0] RBP: ffffffff88e07c80 R08: ffffffff88e7a180 R09: 0000000000000000
[ 65.147598][ C0] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000001
[ 65.155536][ C0] R13: 0000000000000000 R14: 0000000000000060 R15: 0000000000000001
[ 65.163491][ C0] ? default_idle+0x4e/0x360
[ 65.168055][ C0] default_enter_idle+0x71/0xf0
[ 65.172871][ C0] cpuidle_enter_state+0xef/0xfb0
[ 65.177862][ C0] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20
[ 65.184069][ C0] cpuidle_enter+0x4f/0xa0
[ 65.188455][ C0] do_idle+0x45f/0x6e0
[ 65.192490][ C0] ? arch_cpu_idle_exit+0x80/0x80
[ 65.197481][ C0] ? trace_hardirqs_on+0x30/0x240
[ 65.202473][ C0] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20
[ 65.208682][ C0] ? debug_smp_processor_id+0x3c/0x214
[ 65.214119][ C0] cpu_startup_entry+0x1b/0x20
[ 65.218851][ C0] rest_init+0x245/0x37b
[ 65.223063][ C0] arch_call_rest_init+0xe/0x1b
[ 65.227881][ C0] start_kernel+0x904/0x943
[ 65.232356][ C0] ? mem_encrypt_init+0xb/0xb
[ 65.237003][ C0] ? __sanitizer_cov_trace_cons