[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [ 63.239848][ T26] audit: type=1800 audit(1567476267.402:25): pid=8506 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="cron" dev="sda1" ino=2414 res=0 [ 63.261339][ T26] audit: type=1800 audit(1567476267.402:26): pid=8506 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="mcstrans" dev="sda1" ino=2457 res=0 [ 63.282251][ T26] audit: type=1800 audit(1567476267.402:27): pid=8506 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 '10.128.0.212' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 75.573380][ C0] [ 75.575944][ C0] ======================================================== [ 75.583367][ C0] WARNING: possible irq lock inversion dependency detected [ 75.590688][ C0] 5.3.0-rc6-next-20190830 #75 Not tainted [ 75.596382][ C0] -------------------------------------------------------- [ 75.603562][ C0] swapper/0/0 just changed the state of lock: [ 75.609615][ C0] ffff8880997f3b58 (&(&ctx->ctx_lock)->rlock){..-.}, at: free_ioctx_users+0x2d/0x490 [ 75.619066][ C0] but this lock took another, SOFTIRQ-unsafe lock in the past: [ 75.627547][ C0] (&fiq->waitq){+.+.} [ 75.627553][ C0] [ 75.627553][ C0] [ 75.627553][ C0] and interrupts could create inverse lock ordering between them. [ 75.627553][ C0] [ 75.647274][ C0] [ 75.647274][ C0] other info that might help us debug this: [ 75.655514][ C0] Possible interrupt unsafe locking scenario: [ 75.655514][ C0] [ 75.663816][ C0] CPU0 CPU1 [ 75.669169][ C0] ---- ---- [ 75.674505][ C0] lock(&fiq->waitq); [ 75.678562][ C0] local_irq_disable(); [ 75.685289][ C0] lock(&(&ctx->ctx_lock)->rlock); [ 75.692973][ C0] lock(&fiq->waitq); [ 75.699531][ C0] [ 75.703331][ C0] lock(&(&ctx->ctx_lock)->rlock); [ 75.708713][ C0] [ 75.708713][ C0] *** DEADLOCK *** [ 75.708713][ C0] [ 75.717442][ C0] 2 locks held by swapper/0/0: [ 75.722173][ C0] #0: ffffffff88fa7e40 (rcu_callback){....}, at: rcu_core+0x60e/0x1560 [ 75.730483][ C0] #1: ffffffff88fa7e80 (rcu_read_lock_sched){....}, at: percpu_ref_switch_to_atomic_rcu+0x20e/0x570 [ 75.741409][ C0] [ 75.741409][ C0] the shortest dependencies between 2nd lock and 1st lock: [ 75.751296][ C0] -> (&fiq->waitq){+.+.} { [ 75.755774][ C0] HARDIRQ-ON-W at: [ 75.759823][ C0] lock_acquire+0x190/0x410 [ 75.766125][ C0] _raw_spin_lock+0x2f/0x40 [ 75.772427][ C0] flush_bg_queue+0x1f1/0x3b0 [ 75.778901][ C0] fuse_request_queue_background+0x2f8/0x5b0 [ 75.786703][ C0] fuse_request_send_background+0x58/0x110 [ 75.794305][ C0] cuse_channel_open+0x5c3/0x839 [ 75.801135][ C0] misc_open+0x395/0x4c0 [ 75.807178][ C0] chrdev_open+0x245/0x6b0 [ 75.813392][ C0] do_dentry_open+0x4df/0x1250 [ 75.819953][ C0] vfs_open+0xa0/0xd0 [ 75.825931][ C0] path_openat+0x10e9/0x46d0 [ 75.832317][ C0] do_filp_open+0x1a1/0x280 [ 75.838720][ C0] do_sys_open+0x3fe/0x5d0 [ 75.844954][ C0] __x64_sys_openat+0x9d/0x100 [ 75.855772][ C0] do_syscall_64+0xfa/0x760 [ 75.862074][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 75.869759][ C0] SOFTIRQ-ON-W at: [ 75.873807][ C0] lock_acquire+0x190/0x410 [ 75.880107][ C0] _raw_spin_lock+0x2f/0x40 [ 75.886414][ C0] flush_bg_queue+0x1f1/0x3b0 [ 75.892897][ C0] fuse_request_queue_background+0x2f8/0x5b0 [ 75.900673][ C0] fuse_request_send_background+0x58/0x110 [ 75.908283][ C0] cuse_channel_open+0x5c3/0x839 [ 75.915016][ C0] misc_open+0x395/0x4c0 [ 75.921056][ C0] chrdev_open+0x245/0x6b0 [ 75.927270][ C0] do_dentry_open+0x4df/0x1250 [ 75.933831][ C0] vfs_open+0xa0/0xd0 [ 75.940057][ C0] path_openat+0x10e9/0x46d0 [ 75.946447][ C0] do_filp_open+0x1a1/0x280 [ 75.952958][ C0] do_sys_open+0x3fe/0x5d0 [ 75.959170][ C0] __x64_sys_openat+0x9d/0x100 [ 75.965732][ C0] do_syscall_64+0xfa/0x760 [ 75.972033][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 75.979716][ C0] INITIAL USE at: [ 75.983675][ C0] lock_acquire+0x190/0x410 [ 75.989889][ C0] _raw_spin_lock+0x2f/0x40 [ 75.996112][ C0] flush_bg_queue+0x1f1/0x3b0 [ 76.002509][ C0] fuse_request_queue_background+0x2f8/0x5b0 [ 76.010198][ C0] fuse_request_send_background+0x58/0x110 [ 76.017712][ C0] cuse_channel_open+0x5c3/0x839 [ 76.024371][ C0] misc_open+0x395/0x4c0 [ 76.030337][ C0] chrdev_open+0x245/0x6b0 [ 76.036477][ C0] do_dentry_open+0x4df/0x1250 [ 76.042951][ C0] vfs_open+0xa0/0xd0 [ 76.048666][ C0] path_openat+0x10e9/0x46d0 [ 76.054971][ C0] do_filp_open+0x1a1/0x280 [ 76.061184][ C0] do_sys_open+0x3fe/0x5d0 [ 76.067309][ C0] __x64_sys_openat+0x9d/0x100 [ 76.074130][ C0] do_syscall_64+0xfa/0x760 [ 76.080344][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 76.087942][ C0] } [ 76.090530][ C0] ... key at: [] __key.44810+0x0/0x40 [ 76.098053][ C0] ... acquired at: [ 76.101924][ C0] _raw_spin_lock+0x2f/0x40 [ 76.106596][ C0] io_submit_one+0xefa/0x2ef0 [ 76.111451][ C0] __x64_sys_io_submit+0x1bd/0x570 [ 76.116725][ C0] do_syscall_64+0xfa/0x760 [ 76.121383][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 76.127438][ C0] [ 76.129769][ C0] -> (&(&ctx->ctx_lock)->rlock){..-.} { [ 76.135391][ C0] IN-SOFTIRQ-W at: [ 76.139367][ C0] lock_acquire+0x190/0x410 [ 76.145590][ C0] _raw_spin_lock_irq+0x60/0x80 [ 76.152239][ C0] free_ioctx_users+0x2d/0x490 [ 76.158716][ C0] percpu_ref_switch_to_atomic_rcu+0x4c0/0x570 [ 76.166753][ C0] rcu_core+0x581/0x1560 [ 76.172621][ C0] rcu_core_si+0x9/0x10 [ 76.178408][ C0] __do_softirq+0x262/0x98c [ 76.184548][ C0] irq_exit+0x19b/0x1e0 [ 76.190349][ C0] smp_apic_timer_interrupt+0x1a3/0x610 [ 76.197638][ C0] apic_timer_interrupt+0xf/0x20 [ 76.204728][ C0] native_safe_halt+0xe/0x10 [ 76.210948][ C0] default_enter_idle+0x71/0xf0 [ 76.217444][ C0] cpuidle_enter_state+0xef/0xfb0 [ 76.224102][ C0] cpuidle_enter+0x4f/0xa0 [ 76.230163][ C0] do_idle+0x45f/0x6e0 [ 76.235879][ C0] cpu_startup_entry+0x1b/0x20 [ 76.242276][ C0] rest_init+0x245/0x37b [ 76.248154][ C0] arch_call_rest_init+0xe/0x1b [ 76.254656][ C0] start_kernel+0x904/0x943 [ 76.260785][ C0] x86_64_start_reservations+0x29/0x2b [ 76.267909][ C0] x86_64_start_kernel+0x77/0x7b [ 76.274481][ C0] secondary_startup_64+0xa4/0xb0 [ 76.281302][ C0] INITIAL USE at: [ 76.285325][ C0] lock_acquire+0x190/0x410 [ 76.291380][ C0] _raw_spin_lock_irq+0x60/0x80 [ 76.297771][ C0] io_submit_one+0xeb5/0x2ef0 [ 76.303995][ C0] __x64_sys_io_submit+0x1bd/0x570 [ 76.310653][ C0] do_syscall_64+0xfa/0x760 [ 76.316705][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 76.324133][ C0] } [ 76.326615][ C0] ... key at: [] __key.54358+0x0/0x40 [ 76.334220][ C0] ... acquired at: [ 76.338064][ C0] mark_lock+0x517/0x1220 [ 76.342540][ C0] __lock_acquire+0x1e8e/0x4a00 [ 76.347539][ C0] lock_acquire+0x190/0x410 [ 76.352190][ C0] _raw_spin_lock_irq+0x60/0x80 [ 76.357189][ C0] free_ioctx_users+0x2d/0x490 [ 76.362112][ C0] percpu_ref_switch_to_atomic_rcu+0x4c0/0x570 [ 76.368413][ C0] rcu_core+0x581/0x1560 [ 76.372797][ C0] rcu_core_si+0x9/0x10 [ 76.377097][ C0] __do_softirq+0x262/0x98c [ 76.381756][ C0] irq_exit+0x19b/0x1e0 [ 76.386056][ C0] smp_apic_timer_interrupt+0x1a3/0x610 [ 76.391744][ C0] apic_timer_interrupt+0xf/0x20 [ 76.397356][ C0] native_safe_halt+0xe/0x10 [ 76.402108][ C0] default_enter_idle+0x71/0xf0 [ 76.407106][ C0] cpuidle_enter_state+0xef/0xfb0 [ 76.412273][ C0] cpuidle_enter+0x4f/0xa0 [ 76.416839][ C0] do_idle+0x45f/0x6e0 [ 76.421063][ C0] cpu_startup_entry+0x1b/0x20 [ 76.426038][ C0] rest_init+0x245/0x37b [ 76.430434][ C0] arch_call_rest_init+0xe/0x1b [ 76.435464][ C0] start_kernel+0x904/0x943 [ 76.440115][ C0] x86_64_start_reservations+0x29/0x2b [ 76.445726][ C0] x86_64_start_kernel+0x77/0x7b [ 76.450875][ C0] secondary_startup_64+0xa4/0xb0 [ 76.456057][ C0] [ 76.458366][ C0] [ 76.458366][ C0] stack backtrace: [ 76.464244][ C0] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.3.0-rc6-next-20190830 #75 [ 76.472536][ C0] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 76.482583][ C0] Call Trace: [ 76.485852][ C0] [ 76.488687][ C0] dump_stack+0x172/0x1f0 [ 76.492990][ C0] print_irq_inversion_bug.part.0+0x2e4/0x2f1 [ 76.499030][ C0] check_usage_forwards.cold+0x20/0x29 [ 76.504461][ C0] ? check_usage_backwards+0x330/0x330 [ 76.509895][ C0] ? secondary_startup_64+0xa4/0xb0 [ 76.515068][ C0] ? save_trace+0x3e/0x8c0 [ 76.519460][ C0] mark_lock+0x517/0x1220 [ 76.523760][ C0] ? check_usage_backwards+0x330/0x330 [ 76.529191][ C0] __lock_acquire+0x1e8e/0x4a00 [ 76.534017][ C0] ? __kasan_check_read+0x11/0x20 [ 76.539012][ C0] ? mark_lock+0xc2/0x1220 [ 76.543402][ C0] ? mark_held_locks+0xf0/0xf0 [ 76.548137][ C0] lock_acquire+0x190/0x410 [ 76.552626][ C0] ? free_ioctx_users+0x2d/0x490 [ 76.557541][ C0] _raw_spin_lock_irq+0x60/0x80 [ 76.562363][ C0] ? free_ioctx_users+0x2d/0x490 [ 76.567273][ C0] free_ioctx_users+0x2d/0x490 [ 76.572008][ C0] ? rcu_dynticks_curr_cpu_in_eqs+0x54/0xb0 [ 76.577875][ C0] percpu_ref_switch_to_atomic_rcu+0x4c0/0x570 [ 76.584001][ C0] ? percpu_ref_exit+0xd0/0xd0 [ 76.588746][ C0] rcu_core+0x581/0x1560 [ 76.592971][ C0] ? __rcu_read_unlock+0x6b0/0x6b0 [ 76.598055][ C0] ? rcu_read_lock_sched_held+0x9c/0xd0 [ 76.603592][ C0] ? rcu_read_lock_any_held.part.0+0x50/0x50 [ 76.609546][ C0] ? run_rebalance_domains+0x227/0x2d0 [ 76.614988][ C0] rcu_core_si+0x9/0x10 [ 76.619135][ C0] __do_softirq+0x262/0x98c [ 76.623635][ C0] ? sched_clock_cpu+0x1b/0x1b0 [ 76.628471][ C0] irq_exit+0x19b/0x1e0 [ 76.632604][ C0] smp_apic_timer_interrupt+0x1a3/0x610 [ 76.638126][ C0] apic_timer_interrupt+0xf/0x20 [ 76.643031][ C0] [ 76.645946][ C0] RIP: 0010:native_safe_halt+0xe/0x10 [ 76.651361][ 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 [ 76.670952][ C0] RSP: 0018:ffffffff88e07c50 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff13 [ 76.679334][ C0] RAX: 1ffffffff11e5db7 RBX: 0000000000000000 RCX: 0000000000000000 [ 76.687280][ C0] RDX: dffffc0000000000 RSI: 0000000000000006 RDI: ffffffff88e7aa1c [ 76.695246][ C0] RBP: ffffffff88e07c80 R08: ffffffff88e7a180 R09: 0000000000000000 [ 76.703202][ C0] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000001 [ 76.711689][ C0] R13: 0000000000000000 R14: 0000000000000060 R15: 0000000000000001 [ 76.719646][ C0] ? default_idle+0x4e/0x360 [ 76.724212][ C0] default_enter_idle+0x71/0xf0 [ 76.729037][ C0] cpuidle_enter_state+0xef/0xfb0 [ 76.734037][ C0] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 76.740248][ C0] cpuidle_enter+0x4f/0xa0 [ 76.744639][ C0] do_idle+0x45f/0x6e0 [ 76.748691][ C0] ? arch_cpu_idle_exit+0x80/0x80 [ 76.753705][ C0] ? trace_hardirqs_on+0x30/0x240 [ 76.758712][ C0] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 76.764925][ C0] ? debug_smp_processor_id+0x3c/0x214 [ 76.770365][ C0] cpu_startup_entry+0x1b/0x20 [ 76.775101][ C0] rest_init+0x245/0x37b [ 76.779319][ C0] arch_call_rest_init+0xe/0x1b [ 76.784154][ C0] start_kernel+0x904/0x943 [ 76.788630][ C0] ? mem_encrypt_init+0xb/0xb [ 76.793284][ C0] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 76.799530][ C0] ? x86_family+0x41/0x50 [ 76.803833][ C0] ? __sanitizer_cov_trace_const_cmp1+0x1a/0x20 [ 76.810056][ C0] x86_64_start_reservations+0x29/0x2b [ 76.815607][ C0] x86_64_start_kernel+0x77/0x7b [ 76.820522][ C0] secondary_startup_64+0xa4/0xb0