[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [ 61.603473][ T26] audit: type=1800 audit(1567472619.409:25): pid=8512 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="cron" dev="sda1" ino=2414 res=0 [ 61.640746][ T26] audit: type=1800 audit(1567472619.409:26): pid=8512 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="mcstrans" dev="sda1" ino=2457 res=0 [ 61.700258][ T26] audit: type=1800 audit(1567472619.419:27): pid=8512 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 '10.128.1.60' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 75.572842][ C0] [ 75.575217][ C0] ======================================================== [ 75.582409][ C0] WARNING: possible irq lock inversion dependency detected [ 75.589587][ C0] 5.3.0-rc6-next-20190830 #75 Not tainted [ 75.595400][ C0] -------------------------------------------------------- [ 75.602576][ C0] swapper/0/0 just changed the state of lock: [ 75.608747][ C0] ffff8880a42afb58 (&(&ctx->ctx_lock)->rlock){..-.}, at: free_ioctx_users+0x2d/0x490 [ 75.618211][ C0] but this lock took another, SOFTIRQ-unsafe lock in the past: [ 75.625725][ C0] (&fiq->waitq){+.+.} [ 75.625731][ C0] [ 75.625731][ C0] [ 75.625731][ C0] and interrupts could create inverse lock ordering between them. [ 75.625731][ C0] [ 75.644063][ C0] [ 75.644063][ C0] other info that might help us debug this: [ 75.652101][ C0] Possible interrupt unsafe locking scenario: [ 75.652101][ C0] [ 75.660390][ C0] CPU0 CPU1 [ 75.665729][ C0] ---- ---- [ 75.671065][ C0] lock(&fiq->waitq); [ 75.675106][ C0] local_irq_disable(); [ 75.681831][ C0] lock(&(&ctx->ctx_lock)->rlock); [ 75.689525][ C0] lock(&fiq->waitq); [ 75.696080][ C0] [ 75.699969][ C0] lock(&(&ctx->ctx_lock)->rlock); [ 75.705320][ C0] [ 75.705320][ C0] *** DEADLOCK *** [ 75.705320][ C0] [ 75.713444][ C0] 2 locks held by swapper/0/0: [ 75.718184][ C0] #0: ffffffff88fa7e40 (rcu_callback){....}, at: rcu_core+0x60e/0x1560 [ 75.726492][ C0] #1: ffffffff88fa7e80 (rcu_read_lock_sched){....}, at: percpu_ref_switch_to_atomic_rcu+0x20e/0x570 [ 75.737335][ C0] [ 75.737335][ C0] the shortest dependencies between 2nd lock and 1st lock: [ 75.746698][ C0] -> (&fiq->waitq){+.+.} { [ 75.751193][ C0] HARDIRQ-ON-W at: [ 75.755243][ C0] lock_acquire+0x190/0x410 [ 75.761564][ C0] _raw_spin_lock+0x2f/0x40 [ 75.767863][ C0] flush_bg_queue+0x1f1/0x3b0 [ 75.774348][ C0] fuse_request_queue_background+0x2f8/0x5b0 [ 75.782123][ C0] fuse_request_send_background+0x58/0x110 [ 75.789739][ C0] cuse_channel_open+0x5c3/0x839 [ 75.796482][ C0] misc_open+0x395/0x4c0 [ 75.802535][ C0] chrdev_open+0x245/0x6b0 [ 75.808758][ C0] do_dentry_open+0x4df/0x1250 [ 75.815324][ C0] vfs_open+0xa0/0xd0 [ 75.821103][ C0] path_openat+0x10e9/0x46d0 [ 75.827491][ C0] do_filp_open+0x1a1/0x280 [ 75.833827][ C0] do_sys_open+0x3fe/0x5d0 [ 75.840043][ C0] __x64_sys_openat+0x9d/0x100 [ 75.846609][ C0] do_syscall_64+0xfa/0x760 [ 75.852915][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 75.860600][ C0] SOFTIRQ-ON-W at: [ 75.864647][ C0] lock_acquire+0x190/0x410 [ 75.870949][ C0] _raw_spin_lock+0x2f/0x40 [ 75.877270][ C0] flush_bg_queue+0x1f1/0x3b0 [ 75.883742][ C0] fuse_request_queue_background+0x2f8/0x5b0 [ 75.891518][ C0] fuse_request_send_background+0x58/0x110 [ 75.899117][ C0] cuse_channel_open+0x5c3/0x839 [ 75.905859][ C0] misc_open+0x395/0x4c0 [ 75.911897][ C0] chrdev_open+0x245/0x6b0 [ 75.918109][ C0] do_dentry_open+0x4df/0x1250 [ 75.924679][ C0] vfs_open+0xa0/0xd0 [ 75.930458][ C0] path_openat+0x10e9/0x46d0 [ 75.936844][ C0] do_filp_open+0x1a1/0x280 [ 75.943145][ C0] do_sys_open+0x3fe/0x5d0 [ 75.950316][ C0] __x64_sys_openat+0x9d/0x100 [ 75.956891][ C0] do_syscall_64+0xfa/0x760 [ 75.963193][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 75.970888][ C0] INITIAL USE at: [ 75.974863][ C0] lock_acquire+0x190/0x410 [ 75.981100][ C0] _raw_spin_lock+0x2f/0x40 [ 75.987326][ C0] flush_bg_queue+0x1f1/0x3b0 [ 75.993717][ C0] fuse_request_queue_background+0x2f8/0x5b0 [ 76.001406][ C0] fuse_request_send_background+0x58/0x110 [ 76.008921][ C0] cuse_channel_open+0x5c3/0x839 [ 76.015573][ C0] misc_open+0x395/0x4c0 [ 76.021574][ C0] chrdev_open+0x245/0x6b0 [ 76.027712][ C0] do_dentry_open+0x4df/0x1250 [ 76.034193][ C0] vfs_open+0xa0/0xd0 [ 76.039902][ C0] path_openat+0x10e9/0x46d0 [ 76.046221][ C0] do_filp_open+0x1a1/0x280 [ 76.052541][ C0] do_sys_open+0x3fe/0x5d0 [ 76.058681][ C0] __x64_sys_openat+0x9d/0x100 [ 76.065157][ C0] do_syscall_64+0xfa/0x760 [ 76.071387][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 76.078985][ C0] } [ 76.081554][ C0] ... key at: [] __key.44810+0x0/0x40 [ 76.089062][ C0] ... acquired at: [ 76.092948][ C0] _raw_spin_lock+0x2f/0x40 [ 76.097610][ C0] io_submit_one+0xefa/0x2ef0 [ 76.102447][ C0] __x64_sys_io_submit+0x1bd/0x570 [ 76.107731][ C0] do_syscall_64+0xfa/0x760 [ 76.112383][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 76.118418][ C0] [ 76.121673][ C0] -> (&(&ctx->ctx_lock)->rlock){..-.} { [ 76.127191][ C0] IN-SOFTIRQ-W at: [ 76.131165][ C0] lock_acquire+0x190/0x410 [ 76.137293][ C0] _raw_spin_lock_irq+0x60/0x80 [ 76.143777][ C0] free_ioctx_users+0x2d/0x490 [ 76.150358][ C0] percpu_ref_switch_to_atomic_rcu+0x4c0/0x570 [ 76.158247][ C0] rcu_core+0x581/0x1560 [ 76.164202][ C0] rcu_core_si+0x9/0x10 [ 76.170094][ C0] __do_softirq+0x262/0x98c [ 76.176221][ C0] irq_exit+0x19b/0x1e0 [ 76.182028][ C0] smp_apic_timer_interrupt+0x1a3/0x610 [ 76.189209][ C0] apic_timer_interrupt+0xf/0x20 [ 76.195809][ C0] native_safe_halt+0xe/0x10 [ 76.203233][ C0] default_enter_idle+0x71/0xf0 [ 76.209967][ C0] cpuidle_enter_state+0xef/0xfb0 [ 76.216620][ C0] cpuidle_enter+0x4f/0xa0 [ 76.222660][ C0] do_idle+0x45f/0x6e0 [ 76.228350][ C0] cpu_startup_entry+0x1b/0x20 [ 76.234735][ C0] rest_init+0x245/0x37b [ 76.240602][ C0] arch_call_rest_init+0xe/0x1b [ 76.247087][ C0] start_kernel+0x904/0x943 [ 76.253271][ C0] x86_64_start_reservations+0x29/0x2b [ 76.260362][ C0] x86_64_start_kernel+0x77/0x7b [ 76.267019][ C0] secondary_startup_64+0xa4/0xb0 [ 76.273672][ C0] INITIAL USE at: [ 76.277544][ C0] lock_acquire+0x190/0x410 [ 76.283588][ C0] _raw_spin_lock_irq+0x60/0x80 [ 76.290002][ C0] io_submit_one+0xeb5/0x2ef0 [ 76.296219][ C0] __x64_sys_io_submit+0x1bd/0x570 [ 76.302868][ C0] do_syscall_64+0xfa/0x760 [ 76.308908][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 76.316339][ C0] } [ 76.318821][ C0] ... key at: [] __key.54358+0x0/0x40 [ 76.326424][ C0] ... acquired at: [ 76.330206][ C0] mark_lock+0x517/0x1220 [ 76.334683][ C0] __lock_acquire+0x1e8e/0x4a00 [ 76.339688][ C0] lock_acquire+0x190/0x410 [ 76.344349][ C0] _raw_spin_lock_irq+0x60/0x80 [ 76.349346][ C0] free_ioctx_users+0x2d/0x490 [ 76.354273][ C0] percpu_ref_switch_to_atomic_rcu+0x4c0/0x570 [ 76.360569][ C0] rcu_core+0x581/0x1560 [ 76.364965][ C0] rcu_core_si+0x9/0x10 [ 76.369264][ C0] __do_softirq+0x262/0x98c [ 76.373925][ C0] irq_exit+0x19b/0x1e0 [ 76.378228][ C0] smp_apic_timer_interrupt+0x1a3/0x610 [ 76.383939][ C0] apic_timer_interrupt+0xf/0x20 [ 76.389020][ C0] native_safe_halt+0xe/0x10 [ 76.393756][ C0] default_enter_idle+0x71/0xf0 [ 76.398767][ C0] cpuidle_enter_state+0xef/0xfb0 [ 76.403952][ C0] cpuidle_enter+0x4f/0xa0 [ 76.408529][ C0] do_idle+0x45f/0x6e0 [ 76.412831][ C0] cpu_startup_entry+0x1b/0x20 [ 76.417749][ C0] rest_init+0x245/0x37b [ 76.422149][ C0] arch_call_rest_init+0xe/0x1b [ 76.427158][ C0] start_kernel+0x904/0x943 [ 76.431811][ C0] x86_64_start_reservations+0x29/0x2b [ 76.437419][ C0] x86_64_start_kernel+0x77/0x7b [ 76.442515][ C0] secondary_startup_64+0xa4/0xb0 [ 76.447687][ C0] [ 76.449987][ C0] [ 76.449987][ C0] stack backtrace: [ 76.455855][ C0] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.3.0-rc6-next-20190830 #75 [ 76.464246][ C0] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 76.474310][ C0] Call Trace: [ 76.477566][ C0] [ 76.480406][ C0] dump_stack+0x172/0x1f0 [ 76.484712][ C0] print_irq_inversion_bug.part.0+0x2e4/0x2f1 [ 76.490752][ C0] check_usage_forwards.cold+0x20/0x29 [ 76.496186][ C0] ? check_usage_backwards+0x330/0x330 [ 76.501619][ C0] ? save_trace+0x3e/0x8c0 [ 76.506008][ C0] mark_lock+0x517/0x1220 [ 76.510308][ C0] ? check_usage_backwards+0x330/0x330 [ 76.515739][ C0] __lock_acquire+0x1e8e/0x4a00 [ 76.520573][ C0] ? __kasan_check_read+0x11/0x20 [ 76.525573][ C0] ? mark_lock+0xc2/0x1220 [ 76.529963][ C0] ? mark_held_locks+0xf0/0xf0 [ 76.534702][ C0] lock_acquire+0x190/0x410 [ 76.539178][ C0] ? free_ioctx_users+0x2d/0x490 [ 76.544108][ C0] _raw_spin_lock_irq+0x60/0x80 [ 76.548940][ C0] ? free_ioctx_users+0x2d/0x490 [ 76.553850][ C0] free_ioctx_users+0x2d/0x490 [ 76.558589][ C0] ? rcu_dynticks_curr_cpu_in_eqs+0x54/0xb0 [ 76.564467][ C0] percpu_ref_switch_to_atomic_rcu+0x4c0/0x570 [ 76.570598][ C0] ? percpu_ref_exit+0xd0/0xd0 [ 76.575340][ C0] rcu_core+0x581/0x1560 [ 76.579739][ C0] ? __rcu_read_unlock+0x6b0/0x6b0 [ 76.584825][ C0] ? rcu_read_lock_sched_held+0x9c/0xd0 [ 76.590376][ C0] ? rcu_read_lock_any_held.part.0+0x50/0x50 [ 76.596425][ C0] ? run_rebalance_domains+0x227/0x2d0 [ 76.601863][ C0] rcu_core_si+0x9/0x10 [ 76.606006][ C0] __do_softirq+0x262/0x98c [ 76.610486][ C0] ? sched_clock_cpu+0x1b/0x1b0 [ 76.615326][ C0] irq_exit+0x19b/0x1e0 [ 76.619463][ C0] smp_apic_timer_interrupt+0x1a3/0x610 [ 76.624979][ C0] apic_timer_interrupt+0xf/0x20 [ 76.629884][ C0] [ 76.632800][ C0] RIP: 0010:native_safe_halt+0xe/0x10 [ 76.638157][ 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 [ 76.657741][ C0] RSP: 0018:ffffffff88e07c50 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff13 [ 76.666122][ C0] RAX: 1ffffffff11e5db7 RBX: 0000000000000000 RCX: 0000000000000000 [ 76.674066][ C0] RDX: dffffc0000000000 RSI: 0000000000000006 RDI: ffffffff88e7aa1c [ 76.682019][ C0] RBP: ffffffff88e07c80 R08: ffffffff88e7a180 R09: 0000000000000000 [ 76.689974][ C0] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000001 [ 76.697931][ C0] R13: 0000000000000000 R14: 0000000000000060 R15: 0000000000000001 [ 76.705888][ C0] ? default_idle+0x4e/0x360 [ 76.710463][ C0] default_enter_idle+0x71/0xf0 [ 76.715377][ C0] cpuidle_enter_state+0xef/0xfb0 [ 76.720382][ C0] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 76.726595][ C0] cpuidle_enter+0x4f/0xa0 [ 76.730986][ C0] do_idle+0x45f/0x6e0 [ 76.735036][ C0] ? arch_cpu_idle_exit+0x80/0x80 [ 76.740053][ C0] ? trace_hardirqs_on+0x30/0x240 [ 76.745064][ C0] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 76.751285][ C0] ? debug_smp_processor_id+0x3c/0x214 [ 76.756721][ C0] cpu_startup_entry+0x1b/0x20 [ 76.761474][ C0] rest_init+0x245/0x37b [ 76.765712][ C0] arch_call_rest_init+0xe/0x1b [ 76.770548][ C0] start_kernel+0x904/0x943 [ 76.775047][ C0] ? mem_encryp