[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [ 58.211837][ T26] audit: type=1800 audit(1567272095.480:25): pid=8487 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="cron" dev="sda1" ino=2414 res=0 [ 58.257488][ T26] audit: type=1800 audit(1567272095.480:26): pid=8487 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="mcstrans" dev="sda1" ino=2457 res=0 [ 58.295636][ T26] audit: type=1800 audit(1567272095.490:27): pid=8487 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 '10.128.0.170' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 69.657677][ C0] [ 69.660052][ C0] ======================================================== [ 69.667218][ C0] WARNING: possible irq lock inversion dependency detected [ 69.674475][ C0] 5.3.0-rc6-next-20190827 #74 Not tainted [ 69.680166][ C0] -------------------------------------------------------- [ 69.687365][ C0] swapper/0/0 just changed the state of lock: [ 69.693412][ C0] ffff8880963c5b58 (&(&ctx->ctx_lock)->rlock){..-.}, at: free_ioctx_users+0x2d/0x490 [ 69.702962][ C0] but this lock took another, SOFTIRQ-unsafe lock in the past: [ 69.710479][ C0] (&fiq->waitq){+.+.} [ 69.710486][ C0] [ 69.710486][ C0] [ 69.710486][ C0] and interrupts could create inverse lock ordering between them. [ 69.710486][ C0] [ 69.728821][ C0] [ 69.728821][ C0] other info that might help us debug this: [ 69.736963][ C0] Possible interrupt unsafe locking scenario: [ 69.736963][ C0] [ 69.745261][ C0] CPU0 CPU1 [ 69.750699][ C0] ---- ---- [ 69.756147][ C0] lock(&fiq->waitq); [ 69.760277][ C0] local_irq_disable(); [ 69.767090][ C0] lock(&(&ctx->ctx_lock)->rlock); [ 69.774780][ C0] lock(&fiq->waitq); [ 69.781372][ C0] [ 69.785082][ C0] lock(&(&ctx->ctx_lock)->rlock); [ 69.790446][ C0] [ 69.790446][ C0] *** DEADLOCK *** [ 69.790446][ C0] [ 69.798572][ C0] 2 locks held by swapper/0/0: [ 69.803319][ C0] #0: ffffffff88fa7e40 (rcu_callback){....}, at: rcu_core+0x60e/0x1560 [ 69.811639][ C0] #1: ffffffff88fa7e80 (rcu_read_lock_sched){....}, at: percpu_ref_switch_to_atomic_rcu+0x20e/0x570 [ 69.822470][ C0] [ 69.822470][ C0] the shortest dependencies between 2nd lock and 1st lock: [ 69.831903][ C0] -> (&fiq->waitq){+.+.} { [ 69.836378][ C0] HARDIRQ-ON-W at: [ 69.840429][ C0] lock_acquire+0x190/0x410 [ 69.846733][ C0] _raw_spin_lock+0x2f/0x40 [ 69.853036][ C0] flush_bg_queue+0x1f3/0x3c0 [ 69.859517][ C0] fuse_request_queue_background+0x2f8/0x5b0 [ 69.867296][ C0] fuse_request_send_background+0x58/0x110 [ 69.874910][ C0] cuse_channel_open+0x5ba/0x830 [ 69.881656][ C0] misc_open+0x395/0x4c0 [ 69.887702][ C0] chrdev_open+0x245/0x6b0 [ 69.893919][ C0] do_dentry_open+0x4df/0x1250 [ 69.901041][ C0] vfs_open+0xa0/0xd0 [ 69.906832][ C0] path_openat+0x10e9/0x46d0 [ 69.913354][ C0] do_filp_open+0x1a1/0x280 [ 69.919967][ C0] do_sys_open+0x3fe/0x5d0 [ 69.926203][ C0] __x64_sys_openat+0x9d/0x100 [ 69.932878][ C0] do_syscall_64+0xfa/0x760 [ 69.939187][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 69.946891][ C0] SOFTIRQ-ON-W at: [ 69.951140][ C0] lock_acquire+0x190/0x410 [ 69.957450][ C0] _raw_spin_lock+0x2f/0x40 [ 69.969519][ C0] flush_bg_queue+0x1f3/0x3c0 [ 69.976018][ C0] fuse_request_queue_background+0x2f8/0x5b0 [ 69.990463][ C0] fuse_request_send_background+0x58/0x110 [ 69.998074][ C0] cuse_channel_open+0x5ba/0x830 [ 70.004815][ C0] misc_open+0x395/0x4c0 [ 70.010913][ C0] chrdev_open+0x245/0x6b0 [ 70.017131][ C0] do_dentry_open+0x4df/0x1250 [ 70.023696][ C0] vfs_open+0xa0/0xd0 [ 70.029484][ C0] path_openat+0x10e9/0x46d0 [ 70.035881][ C0] do_filp_open+0x1a1/0x280 [ 70.042184][ C0] do_sys_open+0x3fe/0x5d0 [ 70.048489][ C0] __x64_sys_openat+0x9d/0x100 [ 70.055085][ C0] do_syscall_64+0xfa/0x760 [ 70.067988][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 70.075677][ C0] INITIAL USE at: [ 70.079647][ C0] lock_acquire+0x190/0x410 [ 70.085860][ C0] _raw_spin_lock+0x2f/0x40 [ 70.092084][ C0] flush_bg_queue+0x1f3/0x3c0 [ 70.098479][ C0] fuse_request_queue_background+0x2f8/0x5b0 [ 70.106172][ C0] fuse_request_send_background+0x58/0x110 [ 70.113697][ C0] cuse_channel_open+0x5ba/0x830 [ 70.120363][ C0] misc_open+0x395/0x4c0 [ 70.126353][ C0] chrdev_open+0x245/0x6b0 [ 70.132962][ C0] do_dentry_open+0x4df/0x1250 [ 70.139440][ C0] vfs_open+0xa0/0xd0 [ 70.145139][ C0] path_openat+0x10e9/0x46d0 [ 70.151444][ C0] do_filp_open+0x1a1/0x280 [ 70.157663][ C0] do_sys_open+0x3fe/0x5d0 [ 70.183631][ C0] __x64_sys_openat+0x9d/0x100 [ 70.190136][ C0] do_syscall_64+0xfa/0x760 [ 70.196372][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 70.203972][ C0] } [ 70.206545][ C0] ... key at: [] __key.45870+0x0/0x40 [ 70.214059][ C0] ... acquired at: [ 70.218061][ C0] _raw_spin_lock+0x2f/0x40 [ 70.222723][ C0] io_submit_one+0xefa/0x2ef0 [ 70.227557][ C0] __x64_sys_io_submit+0x1bd/0x570 [ 70.232823][ C0] do_syscall_64+0xfa/0x760 [ 70.237486][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 70.243529][ C0] [ 70.245831][ C0] -> (&(&ctx->ctx_lock)->rlock){..-.} { [ 70.251355][ C0] IN-SOFTIRQ-W at: [ 70.255356][ C0] lock_acquire+0x190/0x410 [ 70.261489][ C0] _raw_spin_lock_irq+0x60/0x80 [ 70.267968][ C0] free_ioctx_users+0x2d/0x490 [ 70.274379][ C0] percpu_ref_switch_to_atomic_rcu+0x4c0/0x570 [ 70.282156][ C0] rcu_core+0x581/0x1560 [ 70.288023][ C0] rcu_core_si+0x9/0x10 [ 70.293827][ C0] __do_softirq+0x262/0x98c [ 70.299956][ C0] irq_exit+0x19b/0x1e0 [ 70.305743][ C0] smp_apic_timer_interrupt+0x1a3/0x610 [ 70.312914][ C0] apic_timer_interrupt+0xf/0x20 [ 70.319474][ C0] native_safe_halt+0xe/0x10 [ 70.325708][ C0] default_enter_idle+0x71/0xf0 [ 70.332187][ C0] cpuidle_enter_state+0xef/0xfb0 [ 70.338836][ C0] cpuidle_enter+0x4f/0xa0 [ 70.344881][ C0] do_idle+0x45f/0x6e0 [ 70.350573][ C0] cpu_startup_entry+0x1b/0x20 [ 70.356964][ C0] rest_init+0x245/0x37b [ 70.362837][ C0] arch_call_rest_init+0xe/0x1b [ 70.369330][ C0] start_kernel+0x904/0x943 [ 70.375461][ C0] x86_64_start_reservations+0x29/0x2b [ 70.382541][ C0] x86_64_start_kernel+0x77/0x7b [ 70.389105][ C0] secondary_startup_64+0xa4/0xb0 [ 70.395747][ C0] INITIAL USE at: [ 70.399621][ C0] lock_acquire+0x190/0x410 [ 70.405661][ C0] _raw_spin_lock_irq+0x60/0x80 [ 70.412064][ C0] io_submit_one+0xeb5/0x2ef0 [ 70.418283][ C0] __x64_sys_io_submit+0x1bd/0x570 [ 70.424951][ C0] do_syscall_64+0xfa/0x760 [ 70.431016][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 70.438460][ C0] } [ 70.440968][ C0] ... key at: [] __key.54388+0x0/0x40 [ 70.448397][ C0] ... acquired at: [ 70.452196][ C0] mark_lock+0x517/0x1220 [ 70.456675][ C0] __lock_acquire+0x1e8e/0x4a00 [ 70.461669][ C0] lock_acquire+0x190/0x410 [ 70.466320][ C0] _raw_spin_lock_irq+0x60/0x80 [ 70.471320][ C0] free_ioctx_users+0x2d/0x490 [ 70.476235][ C0] percpu_ref_switch_to_atomic_rcu+0x4c0/0x570 [ 70.482623][ C0] rcu_core+0x581/0x1560 [ 70.487020][ C0] rcu_core_si+0x9/0x10 [ 70.491326][ C0] __do_softirq+0x262/0x98c [ 70.496002][ C0] irq_exit+0x19b/0x1e0 [ 70.500307][ C0] smp_apic_timer_interrupt+0x1a3/0x610 [ 70.505999][ C0] apic_timer_interrupt+0xf/0x20 [ 70.511173][ C0] native_safe_halt+0xe/0x10 [ 70.515949][ C0] default_enter_idle+0x71/0xf0 [ 70.520946][ C0] cpuidle_enter_state+0xef/0xfb0 [ 70.526131][ C0] cpuidle_enter+0x4f/0xa0 [ 70.530699][ C0] do_idle+0x45f/0x6e0 [ 70.534929][ C0] cpu_startup_entry+0x1b/0x20 [ 70.539845][ C0] rest_init+0x245/0x37b [ 70.544246][ C0] arch_call_rest_init+0xe/0x1b [ 70.549243][ C0] start_kernel+0x904/0x943 [ 70.553894][ C0] x86_64_start_reservations+0x29/0x2b [ 70.559512][ C0] x86_64_start_kernel+0x77/0x7b [ 70.564598][ C0] secondary_startup_64+0xa4/0xb0 [ 70.569764][ C0] [ 70.572083][ C0] [ 70.572083][ C0] stack backtrace: [ 70.577957][ C0] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.3.0-rc6-next-20190827 #74 [ 70.586251][ C0] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 70.596315][ C0] Call Trace: [ 70.599578][ C0] [ 70.602414][ C0] dump_stack+0x172/0x1f0 [ 70.606723][ C0] print_irq_inversion_bug.part.0+0x2e4/0x2f1 [ 70.612767][ C0] check_usage_forwards.cold+0x20/0x29 [ 70.618202][ C0] ? check_usage_backwards+0x330/0x330 [ 70.623635][ C0] ? save_trace+0x3e/0x8c0 [ 70.628029][ C0] mark_lock+0x517/0x1220 [ 70.632334][ C0] ? check_usage_backwards+0x330/0x330 [ 70.637767][ C0] __lock_acquire+0x1e8e/0x4a00 [ 70.642610][ C0] ? __kasan_check_read+0x11/0x20 [ 70.647611][ C0] ? mark_lock+0xc2/0x1220 [ 70.652003][ C0] ? mark_held_locks+0xf0/0xf0 [ 70.656743][ C0] lock_acquire+0x190/0x410 [ 70.661224][ C0] ? free_ioctx_users+0x2d/0x490 [ 70.666150][ C0] _raw_spin_lock_irq+0x60/0x80 [ 70.670983][ C0] ? free_ioctx_users+0x2d/0x490 [ 70.675898][ C0] free_ioctx_users+0x2d/0x490 [ 70.680637][ C0] ? rcu_dynticks_curr_cpu_in_eqs+0x54/0xb0 [ 70.686603][ C0] percpu_ref_switch_to_atomic_rcu+0x4c0/0x570 [ 70.692753][ C0] ? percpu_ref_exit+0xd0/0xd0 [ 70.697496][ C0] rcu_core+0x581/0x1560 [ 70.701716][ C0] ? __rcu_read_unlock+0x6b0/0x6b0 [ 70.706823][ C0] ? rcu_read_lock_sched_held+0x9c/0xd0 [ 70.712793][ C0] ? rcu_read_lock_any_held.part.0+0x50/0x50 [ 70.718765][ C0] ? run_rebalance_domains+0x227/0x2d0 [ 70.724202][ C0] rcu_core_si+0x9/0x10 [ 70.728356][ C0] __do_softirq+0x262/0x98c [ 70.732852][ C0] ? sched_clock_cpu+0x1b/0x1b0 [ 70.737786][ C0] irq_exit+0x19b/0x1e0 [ 70.741936][ C0] smp_apic_timer_interrupt+0x1a3/0x610 [ 70.747470][ C0] apic_timer_interrupt+0xf/0x20 [ 70.752382][ C0] [ 70.755319][ C0] RIP: 0010:native_safe_halt+0xe/0x10 [ 70.760673][ C0] Code: 78 26 6a fa eb 8a 90 90 90 90 90 90 e9 07 00 00 00 0f 00 2d 04 3e 65 00 f4 c3 66 90 e9 07 00 00 00 0f 00 2d f4 3d 65 00 fb f4 90 55 48 89 e5 41 57 41 56 41 55 41 54 53 e8 2e 07 1d fa e8 29 [ 70.780356][ C0] RSP: 0018:ffffffff88e07c50 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff13 [ 70.788746][ C0] RAX: 1ffffffff11e5daf RBX: 0000000000000000 RCX: 0000000000000000 [ 70.796694][ C0] RDX: dffffc0000000000 RSI: 0000000000000006 RDI: ffffffff88e7aa1c [ 70.804642][ C0] RBP: ffffffff88e07c80 R08: ffffffff88e7a180 R09: 0000000000000000 [ 70.812593][ C0] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000001 [ 70.820539][ C0] R13: 0000000000000000 R14: 0000000000000060 R15: 0000000000000001 [ 70.828520][ C0] ? default_idle+0x4e/0x360 [ 70.833089][ C0] default_enter_idle+0x71/0xf0 [ 70.837937][ C0] cpuidle_enter_state+0xef/0xfb0 [ 70.842949][ C0] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 70.849169][ C0] cpuidle_enter+0x4f/0xa0 [ 70.853562][ C0] do_idle+0x45f/0x6e0 [ 70.857629][ C0] ? arch_cpu_idle_exit+0x80/0x80 [ 70.862632][ C0] ? trace_hardirqs_off+0x1b0/0x240 [ 70.867812][ C0] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 70.874103][ C0] ? debug_smp_processor_id+0x3c/0x214 [ 70.879559][ C0] cpu_startup_entry+0x1b/0x20 [ 70.884321][ C0] rest_init+0x245/0x37b [ 70.888545][ C0] arch_call_rest_init+0xe/0x1b [ 70.893526][ C0] start_kernel+0x904/0x943 [ 70.898020][ C0] ? mem_encrypt_init+0xb/0xb [ 70.902682][ C0] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 70.908927][ C0] ? x86_family+0x41/0x50