[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [ 53.596781][ T26] audit: type=1800 audit(1567376530.815:25): pid=8463 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="cron" dev="sda1" ino=2414 res=0 [ 53.632005][ T26] audit: type=1800 audit(1567376530.815:26): pid=8463 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="mcstrans" dev="sda1" ino=2457 res=0 [ 53.684544][ T26] audit: type=1800 audit(1567376530.825:27): pid=8463 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 '10.128.1.18' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 63.092022][ C0] [ 63.094395][ C0] ======================================================== [ 63.101606][ C0] WARNING: possible irq lock inversion dependency detected [ 63.108819][ C0] 5.3.0-rc6-next-20190830 #75 Not tainted [ 63.114504][ C0] -------------------------------------------------------- [ 63.121663][ C0] swapper/0/0 just changed the state of lock: [ 63.127693][ C0] ffff888090f75b58 (&(&ctx->ctx_lock)->rlock){..-.}, at: free_ioctx_users+0x2d/0x490 [ 63.137145][ C0] but this lock took another, SOFTIRQ-unsafe lock in the past: [ 63.144668][ C0] (&fiq->waitq){+.+.} [ 63.144674][ C0] [ 63.144674][ C0] [ 63.144674][ C0] and interrupts could create inverse lock ordering between them. [ 63.144674][ C0] [ 63.162981][ C0] [ 63.162981][ C0] other info that might help us debug this: [ 63.171093][ C0] Possible interrupt unsafe locking scenario: [ 63.171093][ C0] [ 63.179423][ C0] CPU0 CPU1 [ 63.184758][ C0] ---- ---- [ 63.190090][ C0] lock(&fiq->waitq); [ 63.194125][ C0] local_irq_disable(); [ 63.200849][ C0] lock(&(&ctx->ctx_lock)->rlock); [ 63.208526][ C0] lock(&fiq->waitq); [ 63.215075][ C0] [ 63.218511][ C0] lock(&(&ctx->ctx_lock)->rlock); [ 63.223848][ C0] [ 63.223848][ C0] *** DEADLOCK *** [ 63.223848][ C0] [ 63.232004][ C0] 2 locks held by swapper/0/0: [ 63.236731][ C0] #0: ffffffff88fa7e40 (rcu_callback){....}, at: rcu_core+0x60e/0x1560 [ 63.245029][ C0] #1: ffffffff88fa7e80 (rcu_read_lock_sched){....}, at: percpu_ref_switch_to_atomic_rcu+0x20e/0x570 [ 63.255860][ C0] [ 63.255860][ C0] the shortest dependencies between 2nd lock and 1st lock: [ 63.265197][ C0] -> (&fiq->waitq){+.+.} { [ 63.269679][ C0] HARDIRQ-ON-W at: [ 63.273747][ C0] lock_acquire+0x190/0x410 [ 63.280041][ C0] _raw_spin_lock+0x2f/0x40 [ 63.286334][ C0] flush_bg_queue+0x1f1/0x3b0 [ 63.292802][ C0] fuse_request_queue_background+0x2f8/0x5b0 [ 63.300571][ C0] fuse_request_send_background+0x58/0x110 [ 63.308166][ C0] cuse_channel_open+0x5c3/0x839 [ 63.314922][ C0] misc_open+0x395/0x4c0 [ 63.320957][ C0] chrdev_open+0x245/0x6b0 [ 63.327165][ C0] do_dentry_open+0x4df/0x1250 [ 63.333723][ C0] vfs_open+0xa0/0xd0 [ 63.339493][ C0] path_openat+0x10e9/0x46d0 [ 63.345889][ C0] do_filp_open+0x1a1/0x280 [ 63.352183][ C0] do_sys_open+0x3fe/0x5d0 [ 63.358392][ C0] __x64_sys_openat+0x9d/0x100 [ 63.364949][ C0] do_syscall_64+0xfa/0x760 [ 63.371244][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 63.378923][ C0] SOFTIRQ-ON-W at: [ 63.382963][ C0] lock_acquire+0x190/0x410 [ 63.389258][ C0] _raw_spin_lock+0x2f/0x40 [ 63.395553][ C0] flush_bg_queue+0x1f1/0x3b0 [ 63.402034][ C0] fuse_request_queue_background+0x2f8/0x5b0 [ 63.409804][ C0] fuse_request_send_background+0x58/0x110 [ 63.417409][ C0] cuse_channel_open+0x5c3/0x839 [ 63.424139][ C0] misc_open+0x395/0x4c0 [ 63.430189][ C0] chrdev_open+0x245/0x6b0 [ 63.436410][ C0] do_dentry_open+0x4df/0x1250 [ 63.442964][ C0] vfs_open+0xa0/0xd0 [ 63.448735][ C0] path_openat+0x10e9/0x46d0 [ 63.455116][ C0] do_filp_open+0x1a1/0x280 [ 63.461411][ C0] do_sys_open+0x3fe/0x5d0 [ 63.467618][ C0] __x64_sys_openat+0x9d/0x100 [ 63.474170][ C0] do_syscall_64+0xfa/0x760 [ 63.480494][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 63.488187][ C0] INITIAL USE at: [ 63.492161][ C0] lock_acquire+0x190/0x410 [ 63.498369][ C0] _raw_spin_lock+0x2f/0x40 [ 63.504588][ C0] flush_bg_queue+0x1f1/0x3b0 [ 63.510974][ C0] fuse_request_queue_background+0x2f8/0x5b0 [ 63.518658][ C0] fuse_request_send_background+0x58/0x110 [ 63.526202][ C0] cuse_channel_open+0x5c3/0x839 [ 63.532853][ C0] misc_open+0x395/0x4c0 [ 63.538801][ C0] chrdev_open+0x245/0x6b0 [ 63.544923][ C0] do_dentry_open+0x4df/0x1250 [ 63.551390][ C0] vfs_open+0xa0/0xd0 [ 63.557075][ C0] path_openat+0x10e9/0x46d0 [ 63.563371][ C0] do_filp_open+0x1a1/0x280 [ 63.569579][ C0] do_sys_open+0x3fe/0x5d0 [ 63.575699][ C0] __x64_sys_openat+0x9d/0x100 [ 63.582255][ C0] do_syscall_64+0xfa/0x760 [ 63.588466][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 63.596059][ C0] } [ 63.598623][ C0] ... key at: [] __key.44810+0x0/0x40 [ 63.606127][ C0] ... acquired at: [ 63.609991][ C0] _raw_spin_lock+0x2f/0x40 [ 63.614637][ C0] io_submit_one+0xefa/0x2ef0 [ 63.619457][ C0] __x64_sys_io_submit+0x1bd/0x570 [ 63.624708][ C0] do_syscall_64+0xfa/0x760 [ 63.629370][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 63.635397][ C0] [ 63.637695][ C0] -> (&(&ctx->ctx_lock)->rlock){..-.} { [ 63.643210][ C0] IN-SOFTIRQ-W at: [ 63.647160][ C0] lock_acquire+0x190/0x410 [ 63.653283][ C0] _raw_spin_lock_irq+0x60/0x80 [ 63.659751][ C0] free_ioctx_users+0x2d/0x490 [ 63.666135][ C0] percpu_ref_switch_to_atomic_rcu+0x4c0/0x570 [ 63.673904][ C0] rcu_core+0x581/0x1560 [ 63.679765][ C0] rcu_core_si+0x9/0x10 [ 63.685539][ C0] __do_softirq+0x262/0x98c [ 63.691678][ C0] irq_exit+0x19b/0x1e0 [ 63.697452][ C0] smp_apic_timer_interrupt+0x1a3/0x610 [ 63.704613][ C0] apic_timer_interrupt+0xf/0x20 [ 63.711169][ C0] native_safe_halt+0xe/0x10 [ 63.717377][ C0] default_enter_idle+0x71/0xf0 [ 63.723848][ C0] cpuidle_enter_state+0xef/0xfb0 [ 63.730488][ C0] cpuidle_enter+0x4f/0xa0 [ 63.736520][ C0] do_idle+0x45f/0x6e0 [ 63.742208][ C0] cpu_startup_entry+0x1b/0x20 [ 63.748586][ C0] rest_init+0x245/0x37b [ 63.754450][ C0] arch_call_rest_init+0xe/0x1b [ 63.760917][ C0] start_kernel+0x904/0x943 [ 63.767039][ C0] x86_64_start_reservations+0x29/0x2b [ 63.774129][ C0] x86_64_start_kernel+0x77/0x7b [ 63.780688][ C0] secondary_startup_64+0xa4/0xb0 [ 63.787325][ C0] INITIAL USE at: [ 63.791193][ C0] lock_acquire+0x190/0x410 [ 63.797233][ C0] _raw_spin_lock_irq+0x60/0x80 [ 63.803614][ C0] io_submit_one+0xeb5/0x2ef0 [ 63.809818][ C0] __x64_sys_io_submit+0x1bd/0x570 [ 63.816474][ C0] do_syscall_64+0xfa/0x760 [ 63.822509][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 63.829928][ C0] } [ 63.832413][ C0] ... key at: [] __key.54358+0x0/0x40 [ 63.839829][ C0] ... acquired at: [ 63.843607][ C0] mark_lock+0x517/0x1220 [ 63.848078][ C0] __lock_acquire+0x1e8e/0x4a00 [ 63.853083][ C0] lock_acquire+0x190/0x410 [ 63.857727][ C0] _raw_spin_lock_irq+0x60/0x80 [ 63.862716][ C0] free_ioctx_users+0x2d/0x490 [ 63.867624][ C0] percpu_ref_switch_to_atomic_rcu+0x4c0/0x570 [ 63.873918][ C0] rcu_core+0x581/0x1560 [ 63.878299][ C0] rcu_core_si+0x9/0x10 [ 63.882595][ C0] __do_softirq+0x262/0x98c [ 63.887238][ C0] irq_exit+0x19b/0x1e0 [ 63.891536][ C0] smp_apic_timer_interrupt+0x1a3/0x610 [ 63.897221][ C0] apic_timer_interrupt+0xf/0x20 [ 63.902302][ C0] native_safe_halt+0xe/0x10 [ 63.907032][ C0] default_enter_idle+0x71/0xf0 [ 63.912023][ C0] cpuidle_enter_state+0xef/0xfb0 [ 63.917191][ C0] cpuidle_enter+0x4f/0xa0 [ 63.921762][ C0] do_idle+0x45f/0x6e0 [ 63.925974][ C0] cpu_startup_entry+0x1b/0x20 [ 63.930891][ C0] rest_init+0x245/0x37b [ 63.935277][ C0] arch_call_rest_init+0xe/0x1b [ 63.940269][ C0] start_kernel+0x904/0x943 [ 63.944913][ C0] x86_64_start_reservations+0x29/0x2b [ 63.950511][ C0] x86_64_start_kernel+0x77/0x7b [ 63.955604][ C0] secondary_startup_64+0xa4/0xb0 [ 63.960761][ C0] [ 63.963058][ C0] [ 63.963058][ C0] stack backtrace: [ 63.968919][ C0] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.3.0-rc6-next-20190830 #75 [ 63.977206][ C0] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 63.987227][ C0] Call Trace: [ 63.990479][ C0] [ 63.993303][ C0] dump_stack+0x172/0x1f0 [ 63.997603][ C0] print_irq_inversion_bug.part.0+0x2e4/0x2f1 [ 64.003660][ C0] check_usage_forwards.cold+0x20/0x29 [ 64.009087][ C0] ? check_usage_backwards+0x330/0x330 [ 64.014515][ C0] ? save_trace+0x3e/0x8c0 [ 64.018909][ C0] mark_lock+0x517/0x1220 [ 64.023209][ C0] ? check_usage_backwards+0x330/0x330 [ 64.028647][ C0] __lock_acquire+0x1e8e/0x4a00 [ 64.033468][ C0] ? __kasan_check_read+0x11/0x20 [ 64.038460][ C0] ? mark_lock+0xc2/0x1220 [ 64.042849][ C0] ? mark_held_locks+0xf0/0xf0 [ 64.047581][ C0] lock_acquire+0x190/0x410 [ 64.052053][ C0] ? free_ioctx_users+0x2d/0x490 [ 64.056960][ C0] _raw_spin_lock_irq+0x60/0x80 [ 64.061776][ C0] ? free_ioctx_users+0x2d/0x490 [ 64.066684][ C0] free_ioctx_users+0x2d/0x490 [ 64.071504][ C0] ? rcu_dynticks_curr_cpu_in_eqs+0x54/0xb0 [ 64.077370][ C0] percpu_ref_switch_to_atomic_rcu+0x4c0/0x570 [ 64.083491][ C0] ? percpu_ref_exit+0xd0/0xd0 [ 64.088221][ C0] rcu_core+0x581/0x1560 [ 64.092433][ C0] ? __rcu_read_unlock+0x6b0/0x6b0 [ 64.097514][ C0] ? rcu_read_lock_sched_held+0x9c/0xd0 [ 64.103029][ C0] ? rcu_read_lock_any_held.part.0+0x50/0x50 [ 64.108978][ C0] ? run_rebalance_domains+0x227/0x2d0 [ 64.114418][ C0] rcu_core_si+0x9/0x10 [ 64.118544][ C0] __do_softirq+0x262/0x98c [ 64.123015][ C0] ? sched_clock_cpu+0x1b/0x1b0 [ 64.128271][ C0] irq_exit+0x19b/0x1e0 [ 64.132401][ C0] smp_apic_timer_interrupt+0x1a3/0x610 [ 64.137914][ C0] apic_timer_interrupt+0xf/0x20 [ 64.142817][ C0] [ 64.145726][ C0] RIP: 0010:native_safe_halt+0xe/0x10 [ 64.151066][ 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 [ 64.170753][ C0] RSP: 0018:ffffffff88e07c50 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff13 [ 64.179136][ C0] RAX: 1ffffffff11e5db7 RBX: 0000000000000000 RCX: 0000000000000000 [ 64.187078][ C0] RDX: dffffc0000000000 RSI: 0000000000000006 RDI: ffffffff88e7aa1c [ 64.195019][ C0] RBP: ffffffff88e07c80 R08: ffffffff88e7a180 R09: 0000000000000000 [ 64.202974][ C0] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000001 [ 64.210913][ C0] R13: 0000000000000000 R14: 0000000000000060 R15: 0000000000000001 [ 64.218865][ C0] ? default_idle+0x4e/0x360 [ 64.223443][ C0] default_enter_idle+0x71/0xf0 [ 64.228267][ C0] cpuidle_enter_state+0xef/0xfb0 [ 64.233267][ C0] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 64.239564][ C0] cpuidle_enter+0x4f/0xa0 [ 64.243966][ C0] do_idle+0x45f/0x6e0 [ 64.248007][ C0] ? arch_cpu_idle_exit+0x80/0x80 [ 64.252997][ C0] ? trace_hardirqs_on+0x30/0x240 [ 64.257990][ C0] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 64.264197][ C0] ? debug_smp_processor_id+0x3c/0x214 [ 64.269628][ C0] cpu_startup_entry+0x1b/0x20 [ 64.274361][ C0] rest_init+0x245/0x37b [ 64.278580][ C0] arch_call_rest_init+0xe/0x1b [ 64.283413][ C0] start_kernel+0x904/0x943 [ 64.287885][ C0] ? mem_encrypt_init+0xb/0xb [ 64.292536][ C0] ? __sanitizer_cov_trace_const_cmp