[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [ 56.262724][ T26] audit: type=1800 audit(1567480044.235:25): pid=8691 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="cron" dev="sda1" ino=2414 res=0 [ 56.300312][ T26] audit: type=1800 audit(1567480044.235:26): pid=8691 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="mcstrans" dev="sda1" ino=2457 res=0 [ 56.339053][ T26] audit: type=1800 audit(1567480044.235:27): pid=8691 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 '10.128.0.221' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 75.619074][ C0] [ 75.621438][ C0] ======================================================== [ 75.628611][ C0] WARNING: possible irq lock inversion dependency detected [ 75.635935][ C0] 5.3.0-rc6-next-20190830 #75 Not tainted [ 75.641633][ C0] -------------------------------------------------------- [ 75.648803][ C0] swapper/0/0 just changed the state of lock: [ 75.654847][ C0] ffff888097d7fb58 (&(&ctx->ctx_lock)->rlock){..-.}, at: free_ioctx_users+0x2d/0x490 [ 75.664415][ C0] but this lock took another, SOFTIRQ-unsafe lock in the past: [ 75.672056][ C0] (&fiq->waitq){+.+.} [ 75.672065][ C0] [ 75.672065][ C0] [ 75.672065][ C0] and interrupts could create inverse lock ordering between them. [ 75.672065][ C0] [ 75.690403][ C0] [ 75.690403][ C0] other info that might help us debug this: [ 75.698452][ C0] Possible interrupt unsafe locking scenario: [ 75.698452][ C0] [ 75.706759][ C0] CPU0 CPU1 [ 75.712102][ C0] ---- ---- [ 75.717438][ C0] lock(&fiq->waitq); [ 75.721490][ C0] local_irq_disable(); [ 75.728231][ C0] lock(&(&ctx->ctx_lock)->rlock); [ 75.735920][ C0] lock(&fiq->waitq); [ 75.742504][ C0] [ 75.745935][ C0] lock(&(&ctx->ctx_lock)->rlock); [ 75.751288][ C0] [ 75.751288][ C0] *** DEADLOCK *** [ 75.751288][ C0] [ 75.759409][ C0] 2 locks held by swapper/0/0: [ 75.764139][ C0] #0: ffffffff88fa7e40 (rcu_callback){....}, at: rcu_core+0x60e/0x1560 [ 75.772465][ C0] #1: ffffffff88fa7e80 (rcu_read_lock_sched){....}, at: percpu_ref_switch_to_atomic_rcu+0x20e/0x570 [ 75.783416][ C0] [ 75.783416][ C0] the shortest dependencies between 2nd lock and 1st lock: [ 75.792879][ C0] -> (&fiq->waitq){+.+.} { [ 75.797471][ C0] HARDIRQ-ON-W at: [ 75.801526][ C0] lock_acquire+0x190/0x410 [ 75.807896][ C0] _raw_spin_lock+0x2f/0x40 [ 75.814200][ C0] flush_bg_queue+0x1f1/0x3b0 [ 75.820678][ C0] fuse_request_queue_background+0x2f8/0x5b0 [ 75.828675][ C0] fuse_request_send_background+0x58/0x110 [ 75.836291][ C0] cuse_channel_open+0x5c3/0x839 [ 75.843032][ C0] misc_open+0x395/0x4c0 [ 75.849105][ C0] chrdev_open+0x245/0x6b0 [ 75.855320][ C0] do_dentry_open+0x4df/0x1250 [ 75.861883][ C0] vfs_open+0xa0/0xd0 [ 75.867677][ C0] path_openat+0x10e9/0x46d0 [ 75.874078][ C0] do_filp_open+0x1a1/0x280 [ 75.880533][ C0] do_sys_open+0x3fe/0x5d0 [ 75.886756][ C0] __x64_sys_openat+0x9d/0x100 [ 75.893421][ C0] do_syscall_64+0xfa/0x760 [ 75.899724][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 75.907430][ C0] SOFTIRQ-ON-W at: [ 75.911477][ C0] lock_acquire+0x190/0x410 [ 75.917776][ C0] _raw_spin_lock+0x2f/0x40 [ 75.924091][ C0] flush_bg_queue+0x1f1/0x3b0 [ 75.930568][ C0] fuse_request_queue_background+0x2f8/0x5b0 [ 75.938355][ C0] fuse_request_send_background+0x58/0x110 [ 75.945957][ C0] cuse_channel_open+0x5c3/0x839 [ 75.952690][ C0] misc_open+0x395/0x4c0 [ 75.958745][ C0] chrdev_open+0x245/0x6b0 [ 75.964963][ C0] do_dentry_open+0x4df/0x1250 [ 75.971526][ C0] vfs_open+0xa0/0xd0 [ 75.977303][ C0] path_openat+0x10e9/0x46d0 [ 75.983704][ C0] do_filp_open+0x1a1/0x280 [ 75.990040][ C0] do_sys_open+0x3fe/0x5d0 [ 75.996269][ C0] __x64_sys_openat+0x9d/0x100 [ 76.002830][ C0] do_syscall_64+0xfa/0x760 [ 76.009133][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 76.016874][ C0] INITIAL USE at: [ 76.020853][ C0] lock_acquire+0x190/0x410 [ 76.027136][ C0] _raw_spin_lock+0x2f/0x40 [ 76.033355][ C0] flush_bg_queue+0x1f1/0x3b0 [ 76.039744][ C0] fuse_request_queue_background+0x2f8/0x5b0 [ 76.047451][ C0] fuse_request_send_background+0x58/0x110 [ 76.054969][ C0] cuse_channel_open+0x5c3/0x839 [ 76.061620][ C0] misc_open+0x395/0x4c0 [ 76.067577][ C0] chrdev_open+0x245/0x6b0 [ 76.073707][ C0] do_dentry_open+0x4df/0x1250 [ 76.080185][ C0] vfs_open+0xa0/0xd0 [ 76.085878][ C0] path_openat+0x10e9/0x46d0 [ 76.092180][ C0] do_filp_open+0x1a1/0x280 [ 76.098396][ C0] do_sys_open+0x3fe/0x5d0 [ 76.104526][ C0] __x64_sys_openat+0x9d/0x100 [ 76.111016][ C0] do_syscall_64+0xfa/0x760 [ 76.117231][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 76.124848][ C0] } [ 76.127421][ C0] ... key at: [] __key.44810+0x0/0x40 [ 76.134951][ C0] ... acquired at: [ 76.138831][ C0] _raw_spin_lock+0x2f/0x40 [ 76.143487][ C0] io_submit_one+0xefa/0x2ef0 [ 76.148310][ C0] __x64_sys_io_submit+0x1bd/0x570 [ 76.153568][ C0] do_syscall_64+0xfa/0x760 [ 76.158221][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 76.164256][ C0] [ 76.166558][ C0] -> (&(&ctx->ctx_lock)->rlock){..-.} { [ 76.172083][ C0] IN-SOFTIRQ-W at: [ 76.176069][ C0] lock_acquire+0x190/0x410 [ 76.182254][ C0] _raw_spin_lock_irq+0x60/0x80 [ 76.188730][ C0] free_ioctx_users+0x2d/0x490 [ 76.195123][ C0] percpu_ref_switch_to_atomic_rcu+0x4c0/0x570 [ 76.202904][ C0] rcu_core+0x581/0x1560 [ 76.208773][ C0] rcu_core_si+0x9/0x10 [ 76.214565][ C0] __do_softirq+0x262/0x98c [ 76.220695][ C0] irq_exit+0x19b/0x1e0 [ 76.226476][ C0] smp_apic_timer_interrupt+0x1a3/0x610 [ 76.233661][ C0] apic_timer_interrupt+0xf/0x20 [ 76.240226][ C0] native_safe_halt+0xe/0x10 [ 76.246456][ C0] default_enter_idle+0x71/0xf0 [ 76.252929][ C0] cpuidle_enter_state+0xef/0xfb0 [ 76.259575][ C0] cpuidle_enter+0x4f/0xa0 [ 76.265615][ C0] do_idle+0x45f/0x6e0 [ 76.271313][ C0] cpu_startup_entry+0x1b/0x20 [ 76.277720][ C0] rest_init+0x245/0x37b [ 76.283589][ C0] arch_call_rest_init+0xe/0x1b [ 76.290077][ C0] start_kernel+0x904/0x943 [ 76.296204][ C0] x86_64_start_reservations+0x29/0x2b [ 76.303400][ C0] x86_64_start_kernel+0x77/0x7b [ 76.309968][ C0] secondary_startup_64+0xa4/0xb0 [ 76.316627][ C0] INITIAL USE at: [ 76.320502][ C0] lock_acquire+0x190/0x410 [ 76.326570][ C0] _raw_spin_lock_irq+0x60/0x80 [ 76.333158][ C0] io_submit_one+0xeb5/0x2ef0 [ 76.339382][ C0] __x64_sys_io_submit+0x1bd/0x570 [ 76.346102][ C0] do_syscall_64+0xfa/0x760 [ 76.352153][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 76.359576][ C0] } [ 76.362063][ C0] ... key at: [] __key.54358+0x0/0x40 [ 76.369488][ C0] ... acquired at: [ 76.373277][ C0] mark_lock+0x517/0x1220 [ 76.377780][ C0] __lock_acquire+0x1e8e/0x4a00 [ 76.382847][ C0] lock_acquire+0x190/0x410 [ 76.387579][ C0] _raw_spin_lock_irq+0x60/0x80 [ 76.392580][ C0] free_ioctx_users+0x2d/0x490 [ 76.397494][ C0] percpu_ref_switch_to_atomic_rcu+0x4c0/0x570 [ 76.403794][ C0] rcu_core+0x581/0x1560 [ 76.408183][ C0] rcu_core_si+0x9/0x10 [ 76.412490][ C0] __do_softirq+0x262/0x98c [ 76.417229][ C0] irq_exit+0x19b/0x1e0 [ 76.421534][ C0] smp_apic_timer_interrupt+0x1a3/0x610 [ 76.427224][ C0] apic_timer_interrupt+0xf/0x20 [ 76.432426][ C0] native_safe_halt+0xe/0x10 [ 76.437187][ C0] default_enter_idle+0x71/0xf0 [ 76.442192][ C0] cpuidle_enter_state+0xef/0xfb0 [ 76.447365][ C0] cpuidle_enter+0x4f/0xa0 [ 76.451998][ C0] do_idle+0x45f/0x6e0 [ 76.456218][ C0] cpu_startup_entry+0x1b/0x20 [ 76.461131][ C0] rest_init+0x245/0x37b [ 76.465535][ C0] arch_call_rest_init+0xe/0x1b [ 76.470552][ C0] start_kernel+0x904/0x943 [ 76.475203][ C0] x86_64_start_reservations+0x29/0x2b [ 76.480831][ C0] x86_64_start_kernel+0x77/0x7b [ 76.486007][ C0] secondary_startup_64+0xa4/0xb0 [ 76.491173][ C0] [ 76.493478][ C0] [ 76.493478][ C0] stack backtrace: [ 76.499374][ C0] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.3.0-rc6-next-20190830 #75 [ 76.507685][ C0] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 76.517715][ C0] Call Trace: [ 76.520996][ C0] [ 76.523836][ C0] dump_stack+0x172/0x1f0 [ 76.528146][ C0] print_irq_inversion_bug.part.0+0x2e4/0x2f1 [ 76.534187][ C0] check_usage_forwards.cold+0x20/0x29 [ 76.539636][ C0] ? check_usage_backwards+0x330/0x330 [ 76.545071][ C0] ? save_trace+0x3e/0x8c0 [ 76.549466][ C0] mark_lock+0x517/0x1220 [ 76.553776][ C0] ? check_usage_backwards+0x330/0x330 [ 76.559218][ C0] __lock_acquire+0x1e8e/0x4a00 [ 76.564040][ C0] ? __kasan_check_read+0x11/0x20 [ 76.569048][ C0] ? mark_lock+0xc2/0x1220 [ 76.573440][ C0] ? mark_held_locks+0xf0/0xf0 [ 76.578180][ C0] lock_acquire+0x190/0x410 [ 76.582675][ C0] ? free_ioctx_users+0x2d/0x490 [ 76.587593][ C0] _raw_spin_lock_irq+0x60/0x80 [ 76.592425][ C0] ? free_ioctx_users+0x2d/0x490 [ 76.597338][ C0] free_ioctx_users+0x2d/0x490 [ 76.602073][ C0] ? rcu_dynticks_curr_cpu_in_eqs+0x54/0xb0 [ 76.607954][ C0] percpu_ref_switch_to_atomic_rcu+0x4c0/0x570 [ 76.614085][ C0] ? percpu_ref_exit+0xd0/0xd0 [ 76.618830][ C0] rcu_core+0x581/0x1560 [ 76.623056][ C0] ? __rcu_read_unlock+0x6b0/0x6b0 [ 76.628148][ C0] ? rcu_read_lock_sched_held+0x9c/0xd0 [ 76.633670][ C0] ? rcu_read_lock_any_held.part.0+0x50/0x50 [ 76.639621][ C0] ? run_rebalance_domains+0x227/0x2d0 [ 76.645053][ C0] rcu_core_si+0x9/0x10 [ 76.649185][ C0] __do_softirq+0x262/0x98c [ 76.653667][ C0] ? sched_clock_cpu+0x1b/0x1b0 [ 76.658496][ C0] irq_exit+0x19b/0x1e0 [ 76.662827][ C0] smp_apic_timer_interrupt+0x1a3/0x610 [ 76.668353][ C0] apic_timer_interrupt+0xf/0x20 [ 76.673281][ C0] [ 76.676198][ C0] RIP: 0010:native_safe_halt+0xe/0x10 [ 76.681545][ 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 [ 76.701126][ C0] RSP: 0018:ffffffff88e07c50 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff13 [ 76.709536][ C0] RAX: 1ffffffff11e5db7 RBX: 0000000000000000 RCX: 0000000000000000 [ 76.717484][ C0] RDX: dffffc0000000000 RSI: 0000000000000006 RDI: ffffffff88e7aa1c [ 76.725433][ C0] RBP: ffffffff88e07c80 R08: ffffffff88e7a180 R09: 0000000000000000 [ 76.733383][ C0] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000001 [ 76.741328][ C0] R13: 0000000000000000 R14: 0000000000000060 R15: 0000000000000001 [ 76.749300][ C0] ? default_idle+0x4e/0x360 [ 76.753868][ C0] default_enter_idle+0x71/0xf0 [ 76.758696][ C0] cpuidle_enter_state+0xef/0xfb0 [ 76.763700][ C0] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 76.770005][ C0] cpuidle_enter+0x4f/0xa0 [ 76.774411][ C0] do_idle+0x45f/0x6e0 [ 76.778467][ C0] ? arch_cpu_idle_exit+0x80/0x80 [ 76.783463][ C0] ? trace_hardirqs_on+0x30/0x240 [ 76.788461][ C0] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 76.794675][ C0] ? debug_smp_processor_id+0x3c/0x214 [ 76.800114][ C0] cpu_startup_entry+0x1b/0x20 [ 76.804862][ C0] rest_init+0x245/0x37b [ 76.809138][ C0] arch_call_rest_init+0xe/0x1b [ 76.813978][ C0] start_kernel+0x904/0x943 [ 76.818479][ C0] ? mem_encrypt_init+0xb/0xb [ 76.823139][