[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [ 56.733850][ T26] audit: type=1800 audit(1567969720.216:25): pid=8432 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="cron" dev="sda1" ino=2414 res=0 [ 56.773376][ T26] audit: type=1800 audit(1567969720.216:26): pid=8432 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="mcstrans" dev="sda1" ino=2457 res=0 [ 56.815403][ T26] audit: type=1800 audit(1567969720.216:27): pid=8432 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[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 Warning: Permanently added '10.128.0.218' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 68.793495][ C0] [ 68.795846][ C0] ======================================================== [ 68.803011][ C0] WARNING: possible irq lock inversion dependency detected [ 68.810180][ C0] 5.3.0-rc6-next-20190830 #75 Not tainted [ 68.815866][ C0] -------------------------------------------------------- [ 68.823031][ C0] swapper/0/0 just changed the state of lock: [ 68.829067][ C0] ffff8880997dfb58 (&(&ctx->ctx_lock)->rlock){..-.}, at: free_ioctx_users+0x2d/0x490 [ 68.838505][ C0] but this lock took another, SOFTIRQ-unsafe lock in the past: [ 68.846016][ C0] (&fiq->waitq){+.+.} [ 68.846022][ C0] [ 68.846022][ C0] [ 68.846022][ C0] and interrupts could create inverse lock ordering between them. [ 68.846022][ C0] [ 68.864350][ C0] [ 68.864350][ C0] other info that might help us debug this: [ 68.872390][ C0] Possible interrupt unsafe locking scenario: [ 68.872390][ C0] [ 68.880692][ C0] CPU0 CPU1 [ 68.886035][ C0] ---- ---- [ 68.891374][ C0] lock(&fiq->waitq); [ 68.895483][ C0] local_irq_disable(); [ 68.902450][ C0] lock(&(&ctx->ctx_lock)->rlock); [ 68.910174][ C0] lock(&fiq->waitq); [ 68.916752][ C0] [ 68.920182][ C0] lock(&(&ctx->ctx_lock)->rlock); [ 68.925544][ C0] [ 68.925544][ C0] *** DEADLOCK *** [ 68.925544][ C0] [ 68.933668][ C0] 2 locks held by swapper/0/0: [ 68.938402][ C0] #0: ffffffff88fa7e40 (rcu_callback){....}, at: rcu_core+0x60e/0x1560 [ 68.946815][ C0] #1: ffffffff88fa7e80 (rcu_read_lock_sched){....}, at: percpu_ref_switch_to_atomic_rcu+0x20e/0x570 [ 68.957640][ C0] [ 68.957640][ C0] the shortest dependencies between 2nd lock and 1st lock: [ 68.967009][ C0] -> (&fiq->waitq){+.+.} { [ 68.971487][ C0] HARDIRQ-ON-W at: [ 68.975533][ C0] lock_acquire+0x190/0x410 [ 68.981849][ C0] _raw_spin_lock+0x2f/0x40 [ 68.988147][ C0] flush_bg_queue+0x1f1/0x3b0 [ 68.994621][ C0] fuse_request_queue_background+0x2f8/0x5b0 [ 69.002399][ C0] fuse_request_send_background+0x58/0x110 [ 69.010002][ C0] cuse_channel_open+0x5c3/0x839 [ 69.016739][ C0] misc_open+0x395/0x4c0 [ 69.022896][ C0] chrdev_open+0x245/0x6b0 [ 69.029112][ C0] do_dentry_open+0x4df/0x1250 [ 69.035673][ C0] vfs_open+0xa0/0xd0 [ 69.041451][ C0] path_openat+0x10e9/0x46d0 [ 69.047837][ C0] do_filp_open+0x1a1/0x280 [ 69.054150][ C0] do_sys_open+0x3fe/0x5d0 [ 69.060362][ C0] __x64_sys_openat+0x9d/0x100 [ 69.066924][ C0] do_syscall_64+0xfa/0x760 [ 69.073222][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 69.080906][ C0] SOFTIRQ-ON-W at: [ 69.084951][ C0] lock_acquire+0x190/0x410 [ 69.091249][ C0] _raw_spin_lock+0x2f/0x40 [ 69.097550][ C0] flush_bg_queue+0x1f1/0x3b0 [ 69.104022][ C0] fuse_request_queue_background+0x2f8/0x5b0 [ 69.111811][ C0] fuse_request_send_background+0x58/0x110 [ 69.119500][ C0] cuse_channel_open+0x5c3/0x839 [ 69.126250][ C0] misc_open+0x395/0x4c0 [ 69.132288][ C0] chrdev_open+0x245/0x6b0 [ 69.138501][ C0] do_dentry_open+0x4df/0x1250 [ 69.145062][ C0] vfs_open+0xa0/0xd0 [ 69.150855][ C0] path_openat+0x10e9/0x46d0 [ 69.157244][ C0] do_filp_open+0x1a1/0x280 [ 69.163545][ C0] do_sys_open+0x3fe/0x5d0 [ 69.169760][ C0] __x64_sys_openat+0x9d/0x100 [ 69.176337][ C0] do_syscall_64+0xfa/0x760 [ 69.182641][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 69.190324][ C0] INITIAL USE at: [ 69.194284][ C0] lock_acquire+0x190/0x410 [ 69.200495][ C0] _raw_spin_lock+0x2f/0x40 [ 69.206706][ C0] flush_bg_queue+0x1f1/0x3b0 [ 69.213100][ C0] fuse_request_queue_background+0x2f8/0x5b0 [ 69.220789][ C0] fuse_request_send_background+0x58/0x110 [ 69.228302][ C0] cuse_channel_open+0x5c3/0x839 [ 69.234954][ C0] misc_open+0x395/0x4c0 [ 69.240934][ C0] chrdev_open+0x245/0x6b0 [ 69.247063][ C0] do_dentry_open+0x4df/0x1250 [ 69.253554][ C0] vfs_open+0xa0/0xd0 [ 69.259247][ C0] path_openat+0x10e9/0x46d0 [ 69.265546][ C0] do_filp_open+0x1a1/0x280 [ 69.271759][ C0] do_sys_open+0x3fe/0x5d0 [ 69.277898][ C0] __x64_sys_openat+0x9d/0x100 [ 69.284372][ C0] do_syscall_64+0xfa/0x760 [ 69.290588][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 69.298184][ C0] } [ 69.300755][ C0] ... key at: [] __key.44810+0x0/0x40 [ 69.308264][ C0] ... acquired at: [ 69.312146][ C0] _raw_spin_lock+0x2f/0x40 [ 69.316799][ C0] io_submit_one+0xefa/0x2ef0 [ 69.321620][ C0] __x64_sys_io_submit+0x1bd/0x570 [ 69.326878][ C0] do_syscall_64+0xfa/0x760 [ 69.331528][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 69.337572][ C0] [ 69.339879][ C0] -> (&(&ctx->ctx_lock)->rlock){..-.} { [ 69.345414][ C0] IN-SOFTIRQ-W at: [ 69.349385][ C0] lock_acquire+0x190/0x410 [ 69.355512][ C0] _raw_spin_lock_irq+0x60/0x80 [ 69.362001][ C0] free_ioctx_users+0x2d/0x490 [ 69.368393][ C0] percpu_ref_switch_to_atomic_rcu+0x4c0/0x570 [ 69.376194][ C0] rcu_core+0x581/0x1560 [ 69.382169][ C0] rcu_core_si+0x9/0x10 [ 69.387948][ C0] __do_softirq+0x262/0x98c [ 69.394076][ C0] irq_exit+0x19b/0x1e0 [ 69.399854][ C0] smp_apic_timer_interrupt+0x1a3/0x610 [ 69.407035][ C0] apic_timer_interrupt+0xf/0x20 [ 69.413595][ C0] native_safe_halt+0xe/0x10 [ 69.419807][ C0] default_enter_idle+0x71/0xf0 [ 69.426280][ C0] cpuidle_enter_state+0xef/0xfb0 [ 69.432926][ C0] cpuidle_enter+0x4f/0xa0 [ 69.438968][ C0] do_idle+0x45f/0x6e0 [ 69.444661][ C0] cpu_startup_entry+0x1b/0x20 [ 69.451044][ C0] rest_init+0x245/0x37b [ 69.456911][ C0] arch_call_rest_init+0xe/0x1b [ 69.463385][ C0] start_kernel+0x904/0x943 [ 69.469943][ C0] x86_64_start_reservations+0x29/0x2b [ 69.477028][ C0] x86_64_start_kernel+0x77/0x7b [ 69.483588][ C0] secondary_startup_64+0xa4/0xb0 [ 69.490246][ C0] INITIAL USE at: [ 69.494135][ C0] lock_acquire+0x190/0x410 [ 69.500187][ C0] _raw_spin_lock_irq+0x60/0x80 [ 69.506576][ C0] io_submit_one+0xeb5/0x2ef0 [ 69.512789][ C0] __x64_sys_io_submit+0x1bd/0x570 [ 69.519437][ C0] do_syscall_64+0xfa/0x760 [ 69.525493][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 69.532931][ C0] } [ 69.535423][ C0] ... key at: [] __key.54358+0x0/0x40 [ 69.542848][ C0] ... acquired at: [ 69.546632][ C0] mark_lock+0x517/0x1220 [ 69.551107][ C0] __lock_acquire+0x1e8e/0x4a00 [ 69.556104][ C0] lock_acquire+0x190/0x410 [ 69.560753][ C0] _raw_spin_lock_irq+0x60/0x80 [ 69.565767][ C0] free_ioctx_users+0x2d/0x490 [ 69.570679][ C0] percpu_ref_switch_to_atomic_rcu+0x4c0/0x570 [ 69.576979][ C0] rcu_core+0x581/0x1560 [ 69.581381][ C0] rcu_core_si+0x9/0x10 [ 69.585699][ C0] __do_softirq+0x262/0x98c [ 69.590349][ C0] irq_exit+0x19b/0x1e0 [ 69.594652][ C0] smp_apic_timer_interrupt+0x1a3/0x610 [ 69.600342][ C0] apic_timer_interrupt+0xf/0x20 [ 69.605426][ C0] native_safe_halt+0xe/0x10 [ 69.610163][ C0] default_enter_idle+0x71/0xf0 [ 69.615159][ C0] cpuidle_enter_state+0xef/0xfb0 [ 69.620328][ C0] cpuidle_enter+0x4f/0xa0 [ 69.624891][ C0] do_idle+0x45f/0x6e0 [ 69.629105][ C0] cpu_startup_entry+0x1b/0x20 [ 69.634012][ C0] rest_init+0x245/0x37b [ 69.638402][ C0] arch_call_rest_init+0xe/0x1b [ 69.643402][ C0] start_kernel+0x904/0x943 [ 69.648053][ C0] x86_64_start_reservations+0x29/0x2b [ 69.653658][ C0] x86_64_start_kernel+0x77/0x7b [ 69.658758][ C0] secondary_startup_64+0xa4/0xb0 [ 69.663944][ C0] [ 69.666244][ C0] [ 69.666244][ C0] stack backtrace: [ 69.672111][ C0] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.3.0-rc6-next-20190830 #75 [ 69.680403][ C0] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 69.690430][ C0] Call Trace: [ 69.693694][ C0] [ 69.696530][ C0] dump_stack+0x172/0x1f0 [ 69.700834][ C0] print_irq_inversion_bug.part.0+0x2e4/0x2f1 [ 69.706875][ C0] check_usage_forwards.cold+0x20/0x29 [ 69.712306][ C0] ? check_usage_backwards+0x330/0x330 [ 69.717738][ C0] ? save_trace+0x3e/0x8c0 [ 69.722145][ C0] mark_lock+0x517/0x1220 [ 69.726462][ C0] ? check_usage_backwards+0x330/0x330 [ 69.731894][ C0] __lock_acquire+0x1e8e/0x4a00 [ 69.736725][ C0] ? __kasan_check_read+0x11/0x20 [ 69.741736][ C0] ? mark_lock+0xc2/0x1220 [ 69.746145][ C0] ? mark_held_locks+0xf0/0xf0 [ 69.750897][ C0] lock_acquire+0x190/0x410 [ 69.755374][ C0] ? free_ioctx_users+0x2d/0x490 [ 69.760285][ C0] _raw_spin_lock_irq+0x60/0x80 [ 69.765108][ C0] ? free_ioctx_users+0x2d/0x490 [ 69.770032][ C0] free_ioctx_users+0x2d/0x490 [ 69.775267][ C0] ? rcu_dynticks_curr_cpu_in_eqs+0x54/0xb0 [ 69.781135][ C0] percpu_ref_switch_to_atomic_rcu+0x4c0/0x570 [ 69.787263][ C0] ? percpu_ref_exit+0xd0/0xd0 [ 69.791999][ C0] rcu_core+0x581/0x1560 [ 69.796216][ C0] ? __rcu_read_unlock+0x6b0/0x6b0 [ 69.801319][ C0] ? rcu_read_lock_sched_held+0x9c/0xd0 [ 69.806841][ C0] ? rcu_read_lock_any_held.part.0+0x50/0x50 [ 69.812794][ C0] ? run_rebalance_domains+0x227/0x2d0 [ 69.818259][ C0] rcu_core_si+0x9/0x10 [ 69.822502][ C0] __do_softirq+0x262/0x98c [ 69.826984][ C0] ? sched_clock_cpu+0x1b/0x1b0 [ 69.831825][ C0] irq_exit+0x19b/0x1e0 [ 69.835962][ C0] smp_apic_timer_interrupt+0x1a3/0x610 [ 69.841485][ C0] apic_timer_interrupt+0xf/0x20 [ 69.846394][ C0] [ 69.849315][ C0] RIP: 0010:native_safe_halt+0xe/0x10 [ 69.854664][ 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 90 55 48 89 e5 41 57 41 56 41 55 41 54 53 e8 5e a7 1c fa e8 69 [ 69.874296][ C0] RSP: 0018:ffffffff88e07c50 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff13 [ 69.882684][ C0] RAX: 1ffffffff11e5db7 RBX: 0000000000000000 RCX: 0000000000000000 [ 69.890644][ C0] RDX: dffffc0000000000 RSI: 0000000000000006 RDI: ffffffff88e7aa1c [ 69.898605][ C0] RBP: ffffffff88e07c80 R08: ffffffff88e7a180 R09: 0000000000000000 [ 69.906549][ C0] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000001 [ 69.914494][ C0] R13: 0000000000000000 R14: 0000000000000060 R15: 0000000000000001 [ 69.922469][ C0] ? default_idle+0x4e/0x360 [ 69.927039][ C0] default_enter_idle+0x71/0xf0 [ 69.931864][ C0] cpuidle_enter_state+0xef/0xfb0 [ 69.936864][ C0] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 69.943090][ C0] cpuidle_enter+0x4f/0xa0 [ 69.947483][ C0] do_idle+0x45f/0x6e0 [ 69.951528][ C0] ? arch_cpu_idle_exit+0x80/0x80 [ 69.956528][ C0] ? trace_hardirqs_on+0x30/0x240 [ 69.961537][ C0] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 69.967767][ C0] ? debug_smp_processor_id+0x3c/0x214 [ 69.973199][ C0] cpu_startup_entry+0x1b/0x20 [ 69.977958][ C0] rest_init+0x245/0x37b [ 69.982176][ C0] arch_call_rest_init+0xe/0x1b [ 69.987000][ C0] start_kernel+0x904/0x943 [ 69.991476][ C0] ? mem_encrypt_init+0xb/0xb [ 69.996128][ C0] ? __sanit