[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [ 62.365449][ T26] audit: type=1800 audit(1568167977.636:25): pid=8600 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="cron" dev="sda1" ino=2414 res=0 [ 62.407101][ T26] audit: type=1800 audit(1568167977.646:26): pid=8600 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="mcstrans" dev="sda1" ino=2457 res=0 [ 62.440013][ T26] audit: type=1800 audit(1568167977.646:27): pid=8600 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 '10.128.0.109' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 80.397134][ C0] [ 80.399497][ C0] ======================================================== [ 80.406668][ C0] WARNING: possible irq lock inversion dependency detected [ 80.413843][ C0] 5.3.0-rc6-next-20190830 #75 Not tainted [ 80.419532][ C0] -------------------------------------------------------- [ 80.426702][ C0] swapper/0/0 just changed the state of lock: [ 80.432744][ C0] ffff8880a7f25b58 (&(&ctx->ctx_lock)->rlock){..-.}, at: free_ioctx_users+0x2d/0x490 [ 80.442241][ C0] but this lock took another, SOFTIRQ-unsafe lock in the past: [ 80.449880][ C0] (&fiq->waitq){+.+.} [ 80.449889][ C0] [ 80.449889][ C0] [ 80.449889][ C0] and interrupts could create inverse lock ordering between them. [ 80.449889][ C0] [ 80.468308][ C0] [ 80.468308][ C0] other info that might help us debug this: [ 80.476623][ C0] Possible interrupt unsafe locking scenario: [ 80.476623][ C0] [ 80.484914][ C0] CPU0 CPU1 [ 80.490270][ C0] ---- ---- [ 80.495881][ C0] lock(&fiq->waitq); [ 80.500007][ C0] local_irq_disable(); [ 80.506819][ C0] lock(&(&ctx->ctx_lock)->rlock); [ 80.514512][ C0] lock(&fiq->waitq); [ 80.521078][ C0] [ 80.524505][ C0] lock(&(&ctx->ctx_lock)->rlock); [ 80.530019][ C0] [ 80.530019][ C0] *** DEADLOCK *** [ 80.530019][ C0] [ 80.538141][ C0] 2 locks held by swapper/0/0: [ 80.542958][ C0] #0: ffffffff88fa7e40 (rcu_callback){....}, at: rcu_core+0x60e/0x1560 [ 80.551385][ C0] #1: ffffffff88fa7e80 (rcu_read_lock_sched){....}, at: percpu_ref_switch_to_atomic_rcu+0x20e/0x570 [ 80.562232][ C0] [ 80.562232][ C0] the shortest dependencies between 2nd lock and 1st lock: [ 80.571594][ C0] -> (&fiq->waitq){+.+.} { [ 80.576072][ C0] HARDIRQ-ON-W at: [ 80.580138][ C0] lock_acquire+0x190/0x410 [ 80.586443][ C0] _raw_spin_lock+0x2f/0x40 [ 80.592745][ C0] flush_bg_queue+0x1f1/0x3b0 [ 80.599219][ C0] fuse_request_queue_background+0x2f8/0x5b0 [ 80.606998][ C0] fuse_request_send_background+0x58/0x110 [ 80.614600][ C0] cuse_channel_open+0x5c3/0x839 [ 80.621332][ C0] misc_open+0x395/0x4c0 [ 80.627396][ C0] chrdev_open+0x245/0x6b0 [ 80.633618][ C0] do_dentry_open+0x4df/0x1250 [ 80.640196][ C0] vfs_open+0xa0/0xd0 [ 80.645978][ C0] path_openat+0x10e9/0x46d0 [ 80.652386][ C0] do_filp_open+0x1a1/0x280 [ 80.658738][ C0] do_sys_open+0x3fe/0x5d0 [ 80.664959][ C0] __x64_sys_openat+0x9d/0x100 [ 80.671527][ C0] do_syscall_64+0xfa/0x760 [ 80.677841][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 80.685540][ C0] SOFTIRQ-ON-W at: [ 80.689620][ C0] lock_acquire+0x190/0x410 [ 80.695925][ C0] _raw_spin_lock+0x2f/0x40 [ 80.702252][ C0] flush_bg_queue+0x1f1/0x3b0 [ 80.708742][ C0] fuse_request_queue_background+0x2f8/0x5b0 [ 80.716545][ C0] fuse_request_send_background+0x58/0x110 [ 80.724249][ C0] cuse_channel_open+0x5c3/0x839 [ 80.730998][ C0] misc_open+0x395/0x4c0 [ 80.737040][ C0] chrdev_open+0x245/0x6b0 [ 80.743265][ C0] do_dentry_open+0x4df/0x1250 [ 80.749827][ C0] vfs_open+0xa0/0xd0 [ 80.755621][ C0] path_openat+0x10e9/0x46d0 [ 80.762214][ C0] do_filp_open+0x1a1/0x280 [ 80.768527][ C0] do_sys_open+0x3fe/0x5d0 [ 80.774839][ C0] __x64_sys_openat+0x9d/0x100 [ 80.781552][ C0] do_syscall_64+0xfa/0x760 [ 80.787888][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 80.795634][ C0] INITIAL USE at: [ 80.799605][ C0] lock_acquire+0x190/0x410 [ 80.805845][ C0] _raw_spin_lock+0x2f/0x40 [ 80.812071][ C0] flush_bg_queue+0x1f1/0x3b0 [ 80.818464][ C0] fuse_request_queue_background+0x2f8/0x5b0 [ 80.826184][ C0] fuse_request_send_background+0x58/0x110 [ 80.833711][ C0] cuse_channel_open+0x5c3/0x839 [ 80.840369][ C0] misc_open+0x395/0x4c0 [ 80.846325][ C0] chrdev_open+0x245/0x6b0 [ 80.853503][ C0] do_dentry_open+0x4df/0x1250 [ 80.859977][ C0] vfs_open+0xa0/0xd0 [ 80.865670][ C0] path_openat+0x10e9/0x46d0 [ 80.871982][ C0] do_filp_open+0x1a1/0x280 [ 80.878191][ C0] do_sys_open+0x3fe/0x5d0 [ 80.884495][ C0] __x64_sys_openat+0x9d/0x100 [ 80.890984][ C0] do_syscall_64+0xfa/0x760 [ 80.897195][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 80.904809][ C0] } [ 80.907377][ C0] ... key at: [] __key.44810+0x0/0x40 [ 80.915064][ C0] ... acquired at: [ 80.918933][ C0] _raw_spin_lock+0x2f/0x40 [ 80.923580][ C0] io_submit_one+0xefa/0x2ef0 [ 80.928411][ C0] __x64_sys_io_submit+0x1bd/0x570 [ 80.933763][ C0] do_syscall_64+0xfa/0x760 [ 80.938421][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 80.944460][ C0] [ 80.946759][ C0] -> (&(&ctx->ctx_lock)->rlock){..-.} { [ 80.952277][ C0] IN-SOFTIRQ-W at: [ 80.956255][ C0] lock_acquire+0x190/0x410 [ 80.962377][ C0] _raw_spin_lock_irq+0x60/0x80 [ 80.968859][ C0] free_ioctx_users+0x2d/0x490 [ 80.975244][ C0] percpu_ref_switch_to_atomic_rcu+0x4c0/0x570 [ 80.983026][ C0] rcu_core+0x581/0x1560 [ 80.988888][ C0] rcu_core_si+0x9/0x10 [ 80.994710][ C0] __do_softirq+0x262/0x98c [ 81.000848][ C0] irq_exit+0x19b/0x1e0 [ 81.006630][ C0] smp_apic_timer_interrupt+0x1a3/0x610 [ 81.013804][ C0] apic_timer_interrupt+0xf/0x20 [ 81.021263][ C0] native_safe_halt+0xe/0x10 [ 81.027482][ C0] default_enter_idle+0x71/0xf0 [ 81.034156][ C0] cpuidle_enter_state+0xef/0xfb0 [ 81.040801][ C0] cpuidle_enter+0x4f/0xa0 [ 81.046858][ C0] do_idle+0x45f/0x6e0 [ 81.052557][ C0] cpu_startup_entry+0x1b/0x20 [ 81.058959][ C0] rest_init+0x245/0x37b [ 81.064830][ C0] arch_call_rest_init+0xe/0x1b [ 81.071302][ C0] start_kernel+0x904/0x943 [ 81.077463][ C0] x86_64_start_reservations+0x29/0x2b [ 81.084543][ C0] x86_64_start_kernel+0x77/0x7b [ 81.091101][ C0] secondary_startup_64+0xa4/0xb0 [ 81.097741][ C0] INITIAL USE at: [ 81.101612][ C0] lock_acquire+0x190/0x410 [ 81.107649][ C0] _raw_spin_lock_irq+0x60/0x80 [ 81.114033][ C0] io_submit_one+0xeb5/0x2ef0 [ 81.120251][ C0] __x64_sys_io_submit+0x1bd/0x570 [ 81.126899][ C0] do_syscall_64+0xfa/0x760 [ 81.132936][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 81.140365][ C0] } [ 81.142845][ C0] ... key at: [] __key.54358+0x0/0x40 [ 81.150266][ C0] ... acquired at: [ 81.154049][ C0] mark_lock+0x517/0x1220 [ 81.158532][ C0] __lock_acquire+0x1e8e/0x4a00 [ 81.163528][ C0] lock_acquire+0x190/0x410 [ 81.168177][ C0] _raw_spin_lock_irq+0x60/0x80 [ 81.173170][ C0] free_ioctx_users+0x2d/0x490 [ 81.178301][ C0] percpu_ref_switch_to_atomic_rcu+0x4c0/0x570 [ 81.184596][ C0] rcu_core+0x581/0x1560 [ 81.188984][ C0] rcu_core_si+0x9/0x10 [ 81.193294][ C0] __do_softirq+0x262/0x98c [ 81.197955][ C0] irq_exit+0x19b/0x1e0 [ 81.202254][ C0] smp_apic_timer_interrupt+0x1a3/0x610 [ 81.207952][ C0] apic_timer_interrupt+0xf/0x20 [ 81.213034][ C0] native_safe_halt+0xe/0x10 [ 81.217861][ C0] default_enter_idle+0x71/0xf0 [ 81.222862][ C0] cpuidle_enter_state+0xef/0xfb0 [ 81.228042][ C0] cpuidle_enter+0x4f/0xa0 [ 81.232603][ C0] do_idle+0x45f/0x6e0 [ 81.236825][ C0] cpu_startup_entry+0x1b/0x20 [ 81.241745][ C0] rest_init+0x245/0x37b [ 81.246135][ C0] arch_call_rest_init+0xe/0x1b [ 81.251128][ C0] start_kernel+0x904/0x943 [ 81.255778][ C0] x86_64_start_reservations+0x29/0x2b [ 81.261392][ C0] x86_64_start_kernel+0x77/0x7b [ 81.266474][ C0] secondary_startup_64+0xa4/0xb0 [ 81.271723][ C0] [ 81.274031][ C0] [ 81.274031][ C0] stack backtrace: [ 81.279907][ C0] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.3.0-rc6-next-20190830 #75 [ 81.288477][ C0] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 81.298507][ C0] Call Trace: [ 81.301762][ C0] [ 81.304592][ C0] dump_stack+0x172/0x1f0 [ 81.309512][ C0] print_irq_inversion_bug.part.0+0x2e4/0x2f1 [ 81.315809][ C0] check_usage_forwards.cold+0x20/0x29 [ 81.321276][ C0] ? check_usage_backwards+0x330/0x330 [ 81.327148][ C0] ? save_trace+0x3e/0x8c0 [ 81.332516][ C0] mark_lock+0x517/0x1220 [ 81.336819][ C0] ? check_usage_backwards+0x330/0x330 [ 81.342351][ C0] __lock_acquire+0x1e8e/0x4a00 [ 81.347183][ C0] ? __kasan_check_read+0x11/0x20 [ 81.352190][ C0] ? mark_lock+0xc2/0x1220 [ 81.356596][ C0] ? mark_held_locks+0xf0/0xf0 [ 81.361343][ C0] lock_acquire+0x190/0x410 [ 81.365819][ C0] ? free_ioctx_users+0x2d/0x490 [ 81.370732][ C0] _raw_spin_lock_irq+0x60/0x80 [ 81.375552][ C0] ? free_ioctx_users+0x2d/0x490 [ 81.380635][ C0] free_ioctx_users+0x2d/0x490 [ 81.385398][ C0] ? rcu_dynticks_curr_cpu_in_eqs+0x54/0xb0 [ 81.391283][ C0] percpu_ref_switch_to_atomic_rcu+0x4c0/0x570 [ 81.397414][ C0] ? percpu_ref_exit+0xd0/0xd0 [ 81.402153][ C0] rcu_core+0x581/0x1560 [ 81.406372][ C0] ? __rcu_read_unlock+0x6b0/0x6b0 [ 81.411466][ C0] ? rcu_read_lock_sched_held+0x9c/0xd0 [ 81.416983][ C0] ? rcu_read_lock_any_held.part.0+0x50/0x50 [ 81.423027][ C0] ? run_rebalance_domains+0x227/0x2d0 [ 81.428475][ C0] rcu_core_si+0x9/0x10 [ 81.432768][ C0] __do_softirq+0x262/0x98c [ 81.437258][ C0] ? sched_clock_cpu+0x1b/0x1b0 [ 81.442220][ C0] irq_exit+0x19b/0x1e0 [ 81.446359][ C0] smp_apic_timer_interrupt+0x1a3/0x610 [ 81.451897][ C0] apic_timer_interrupt+0xf/0x20 [ 81.456895][ C0] [ 81.459826][ C0] RIP: 0010:native_safe_halt+0xe/0x10 [ 81.465174][ 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 [ 81.485045][ C0] RSP: 0018:ffffffff88e07c50 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff13 [ 81.493710][ C0] RAX: 1ffffffff11e5db7 RBX: 0000000000000000 RCX: 0000000000000000 [ 81.501668][ C0] RDX: dffffc0000000000 RSI: 0000000000000006 RDI: ffffffff88e7aa1c [ 81.509626][ C0] RBP: ffffffff88e07c80 R08: ffffffff88e7a180 R09: 0000000000000000 [ 81.517581][ C0] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000001 [ 81.525906][ C0] R13: 0000000000000000 R14: 0000000000000060 R15: 0000000000000001 [ 81.533890][ C0] ? default_idle+0x4e/0x360 [ 81.538457][ C0] default_enter_idle+0x71/0xf0 [ 81.543290][ C0] cpuidle_enter_state+0xef/0xfb0 [ 81.548287][ C0] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 81.554512][ C0] cpuidle_enter+0x4f/0xa0 [ 81.558909][ C0] do_idle+0x45f/0x6e0 [ 81.562968][ C0] ? arch_cpu_idle_exit+0x80/0x80 [ 81.567976][ C0] ? trace_hardirqs_on+0x30/0x240 [ 81.572982][ C0] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 81.579206][ C0] ? debug_smp_processor_id+0x3c/0x214 [ 81.584635][ C0] cpu_startup_entry+0x1b/0x20 [ 81.589380][ C0] rest_init+0x245/0x37b [ 81.593608][ C0] arch_call_rest_init+0xe/0x1b [ 81.598432][ C0] start_kernel+0x904/0x94