[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [ 58.115321][ T26] audit: type=1800 audit(1567471591.736:25): pid=8908 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="cron" dev="sda1" ino=2414 res=0 [ 58.137484][ T26] audit: type=1800 audit(1567471591.736:26): pid=8908 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="mcstrans" dev="sda1" ino=2457 res=0 [ 58.190334][ T26] audit: type=1800 audit(1567471591.746:27): pid=8908 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 '10.128.0.196' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 68.210710][ C0] [ 68.213407][ C0] ======================================================== [ 68.221176][ C0] WARNING: possible irq lock inversion dependency detected [ 68.228816][ C0] 5.3.0-rc6-next-20190830 #75 Not tainted [ 68.235045][ C0] -------------------------------------------------------- [ 68.242957][ C0] swapper/0/0 just changed the state of lock: [ 68.249111][ C0] ffff88808dea9b58 (&(&ctx->ctx_lock)->rlock){..-.}, at: free_ioctx_users+0x2d/0x490 [ 68.258720][ C0] but this lock took another, SOFTIRQ-unsafe lock in the past: [ 68.267186][ C0] (&fiq->waitq){+.+.} [ 68.267196][ C0] [ 68.267196][ C0] [ 68.267196][ C0] and interrupts could create inverse lock ordering between them. [ 68.267196][ C0] [ 68.287152][ C0] [ 68.287152][ C0] other info that might help us debug this: [ 68.295955][ C0] Possible interrupt unsafe locking scenario: [ 68.295955][ C0] [ 68.305265][ C0] CPU0 CPU1 [ 68.311070][ C0] ---- ---- [ 68.316818][ C0] lock(&fiq->waitq); [ 68.321028][ C0] local_irq_disable(); [ 68.328283][ C0] lock(&(&ctx->ctx_lock)->rlock); [ 68.336325][ C0] lock(&fiq->waitq); [ 68.343063][ C0] [ 68.346529][ C0] lock(&(&ctx->ctx_lock)->rlock); [ 68.352011][ C0] [ 68.352011][ C0] *** DEADLOCK *** [ 68.352011][ C0] [ 68.360260][ C0] 2 locks held by swapper/0/0: [ 68.365503][ C0] #0: ffffffff88fa7e40 (rcu_callback){....}, at: rcu_core+0x60e/0x1560 [ 68.374322][ C0] #1: ffffffff88fa7e80 (rcu_read_lock_sched){....}, at: percpu_ref_switch_to_atomic_rcu+0x20e/0x570 [ 68.385691][ C0] [ 68.385691][ C0] the shortest dependencies between 2nd lock and 1st lock: [ 68.395804][ C0] -> (&fiq->waitq){+.+.} { [ 68.400483][ C0] HARDIRQ-ON-W at: [ 68.405226][ C0] lock_acquire+0x190/0x410 [ 68.411882][ C0] _raw_spin_lock+0x2f/0x40 [ 68.418217][ C0] flush_bg_queue+0x1f1/0x3b0 [ 68.424920][ C0] fuse_request_queue_background+0x2f8/0x5b0 [ 68.433013][ C0] fuse_request_send_background+0x58/0x110 [ 68.440802][ C0] cuse_channel_open+0x5c3/0x839 [ 68.447752][ C0] misc_open+0x395/0x4c0 [ 68.453969][ C0] chrdev_open+0x245/0x6b0 [ 68.460191][ C0] do_dentry_open+0x4df/0x1250 [ 68.466788][ C0] vfs_open+0xa0/0xd0 [ 68.472664][ C0] path_openat+0x10e9/0x46d0 [ 68.479135][ C0] do_filp_open+0x1a1/0x280 [ 68.485647][ C0] do_sys_open+0x3fe/0x5d0 [ 68.492023][ C0] __x64_sys_openat+0x9d/0x100 [ 68.498884][ C0] do_syscall_64+0xfa/0x760 [ 68.505568][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 68.513395][ C0] SOFTIRQ-ON-W at: [ 68.517696][ C0] lock_acquire+0x190/0x410 [ 68.525949][ C0] _raw_spin_lock+0x2f/0x40 [ 68.532526][ C0] flush_bg_queue+0x1f1/0x3b0 [ 68.539881][ C0] fuse_request_queue_background+0x2f8/0x5b0 [ 68.547950][ C0] fuse_request_send_background+0x58/0x110 [ 68.557820][ C0] cuse_channel_open+0x5c3/0x839 [ 68.564827][ C0] misc_open+0x395/0x4c0 [ 68.571532][ C0] chrdev_open+0x245/0x6b0 [ 68.577952][ C0] do_dentry_open+0x4df/0x1250 [ 68.584919][ C0] vfs_open+0xa0/0xd0 [ 68.591333][ C0] path_openat+0x10e9/0x46d0 [ 68.598166][ C0] do_filp_open+0x1a1/0x280 [ 68.606059][ C0] do_sys_open+0x3fe/0x5d0 [ 68.612486][ C0] __x64_sys_openat+0x9d/0x100 [ 68.619373][ C0] do_syscall_64+0xfa/0x760 [ 68.625850][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 68.633995][ C0] INITIAL USE at: [ 68.637991][ C0] lock_acquire+0x190/0x410 [ 68.644353][ C0] _raw_spin_lock+0x2f/0x40 [ 68.650695][ C0] flush_bg_queue+0x1f1/0x3b0 [ 68.657826][ C0] fuse_request_queue_background+0x2f8/0x5b0 [ 68.665933][ C0] fuse_request_send_background+0x58/0x110 [ 68.673605][ C0] cuse_channel_open+0x5c3/0x839 [ 68.680376][ C0] misc_open+0x395/0x4c0 [ 68.686765][ C0] chrdev_open+0x245/0x6b0 [ 68.692925][ C0] do_dentry_open+0x4df/0x1250 [ 68.699995][ C0] vfs_open+0xa0/0xd0 [ 68.705963][ C0] path_openat+0x10e9/0x46d0 [ 68.713033][ C0] do_filp_open+0x1a1/0x280 [ 68.720888][ C0] do_sys_open+0x3fe/0x5d0 [ 68.727540][ C0] __x64_sys_openat+0x9d/0x100 [ 68.734615][ C0] do_syscall_64+0xfa/0x760 [ 68.741011][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 68.749008][ C0] } [ 68.751828][ C0] ... key at: [] __key.44810+0x0/0x40 [ 68.760432][ C0] ... acquired at: [ 68.764362][ C0] _raw_spin_lock+0x2f/0x40 [ 68.770351][ C0] io_submit_one+0xefa/0x2ef0 [ 68.775513][ C0] __x64_sys_io_submit+0x1bd/0x570 [ 68.780936][ C0] do_syscall_64+0xfa/0x760 [ 68.786121][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 68.792642][ C0] [ 68.795076][ C0] -> (&(&ctx->ctx_lock)->rlock){..-.} { [ 68.800929][ C0] IN-SOFTIRQ-W at: [ 68.804929][ C0] lock_acquire+0x190/0x410 [ 68.811322][ C0] _raw_spin_lock_irq+0x60/0x80 [ 68.818067][ C0] free_ioctx_users+0x2d/0x490 [ 68.824830][ C0] percpu_ref_switch_to_atomic_rcu+0x4c0/0x570 [ 68.833222][ C0] rcu_core+0x581/0x1560 [ 68.840136][ C0] rcu_core_si+0x9/0x10 [ 68.846032][ C0] __do_softirq+0x262/0x98c [ 68.852314][ C0] irq_exit+0x19b/0x1e0 [ 68.858120][ C0] smp_apic_timer_interrupt+0x1a3/0x610 [ 68.865330][ C0] apic_timer_interrupt+0xf/0x20 [ 68.871920][ C0] native_safe_halt+0xe/0x10 [ 68.878157][ C0] default_enter_idle+0x71/0xf0 [ 68.884799][ C0] cpuidle_enter_state+0xef/0xfb0 [ 68.891460][ C0] cpuidle_enter+0x4f/0xa0 [ 68.897514][ C0] do_idle+0x45f/0x6e0 [ 68.903370][ C0] cpu_startup_entry+0x1b/0x20 [ 68.909767][ C0] rest_init+0x245/0x37b [ 68.915804][ C0] arch_call_rest_init+0xe/0x1b [ 68.922303][ C0] start_kernel+0x904/0x943 [ 68.928461][ C0] x86_64_start_reservations+0x29/0x2b [ 68.936910][ C0] x86_64_start_kernel+0x77/0x7b [ 68.943686][ C0] secondary_startup_64+0xa4/0xb0 [ 68.950673][ C0] INITIAL USE at: [ 68.954579][ C0] lock_acquire+0x190/0x410 [ 68.960831][ C0] _raw_spin_lock_irq+0x60/0x80 [ 68.968865][ C0] io_submit_one+0xeb5/0x2ef0 [ 68.975592][ C0] __x64_sys_io_submit+0x1bd/0x570 [ 68.982996][ C0] do_syscall_64+0xfa/0x760 [ 68.990921][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 68.998762][ C0] } [ 69.001429][ C0] ... key at: [] __key.54358+0x0/0x40 [ 69.009690][ C0] ... acquired at: [ 69.013815][ C0] mark_lock+0x517/0x1220 [ 69.018302][ C0] __lock_acquire+0x1e8e/0x4a00 [ 69.023326][ C0] lock_acquire+0x190/0x410 [ 69.028166][ C0] _raw_spin_lock_irq+0x60/0x80 [ 69.033193][ C0] free_ioctx_users+0x2d/0x490 [ 69.038573][ C0] percpu_ref_switch_to_atomic_rcu+0x4c0/0x570 [ 69.044914][ C0] rcu_core+0x581/0x1560 [ 69.049453][ C0] rcu_core_si+0x9/0x10 [ 69.053970][ C0] __do_softirq+0x262/0x98c [ 69.058745][ C0] irq_exit+0x19b/0x1e0 [ 69.063578][ C0] smp_apic_timer_interrupt+0x1a3/0x610 [ 69.069987][ C0] apic_timer_interrupt+0xf/0x20 [ 69.076673][ C0] native_safe_halt+0xe/0x10 [ 69.081850][ C0] default_enter_idle+0x71/0xf0 [ 69.087349][ C0] cpuidle_enter_state+0xef/0xfb0 [ 69.093012][ C0] cpuidle_enter+0x4f/0xa0 [ 69.097694][ C0] do_idle+0x45f/0x6e0 [ 69.101918][ C0] cpu_startup_entry+0x1b/0x20 [ 69.106836][ C0] rest_init+0x245/0x37b [ 69.111506][ C0] arch_call_rest_init+0xe/0x1b [ 69.116787][ C0] start_kernel+0x904/0x943 [ 69.121580][ C0] x86_64_start_reservations+0x29/0x2b [ 69.127654][ C0] x86_64_start_kernel+0x77/0x7b [ 69.133253][ C0] secondary_startup_64+0xa4/0xb0 [ 69.138476][ C0] [ 69.140784][ C0] [ 69.140784][ C0] stack backtrace: [ 69.147849][ C0] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.3.0-rc6-next-20190830 #75 [ 69.156172][ C0] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 69.166880][ C0] Call Trace: [ 69.170619][ C0] [ 69.173654][ C0] dump_stack+0x172/0x1f0 [ 69.178443][ C0] print_irq_inversion_bug.part.0+0x2e4/0x2f1 [ 69.185402][ C0] check_usage_forwards.cold+0x20/0x29 [ 69.191589][ C0] ? check_usage_backwards+0x330/0x330 [ 69.199026][ C0] ? save_trace+0x3e/0x8c0 [ 69.204141][ C0] mark_lock+0x517/0x1220 [ 69.209584][ C0] ? check_usage_backwards+0x330/0x330 [ 69.215435][ C0] __lock_acquire+0x1e8e/0x4a00 [ 69.220533][ C0] ? __kasan_check_read+0x11/0x20 [ 69.226338][ C0] ? mark_lock+0xc2/0x1220 [ 69.231448][ C0] ? mark_held_locks+0xf0/0xf0 [ 69.237244][ C0] lock_acquire+0x190/0x410 [ 69.243173][ C0] ? free_ioctx_users+0x2d/0x490 [ 69.248466][ C0] _raw_spin_lock_irq+0x60/0x80 [ 69.253419][ C0] ? free_ioctx_users+0x2d/0x490 [ 69.258418][ C0] free_ioctx_users+0x2d/0x490 [ 69.264908][ C0] ? rcu_dynticks_curr_cpu_in_eqs+0x54/0xb0 [ 69.271112][ C0] percpu_ref_switch_to_atomic_rcu+0x4c0/0x570 [ 69.277272][ C0] ? percpu_ref_exit+0xd0/0xd0 [ 69.282177][ C0] rcu_core+0x581/0x1560 [ 69.286704][ C0] ? __rcu_read_unlock+0x6b0/0x6b0 [ 69.292005][ C0] ? rcu_read_lock_sched_held+0x9c/0xd0 [ 69.297928][ C0] ? rcu_read_lock_any_held.part.0+0x50/0x50 [ 69.304916][ C0] ? run_rebalance_domains+0x227/0x2d0 [ 69.310642][ C0] rcu_core_si+0x9/0x10 [ 69.316009][ C0] __do_softirq+0x262/0x98c [ 69.321382][ C0] ? sched_clock_cpu+0x1b/0x1b0 [ 69.326937][ C0] irq_exit+0x19b/0x1e0 [ 69.331339][ C0] smp_apic_timer_interrupt+0x1a3/0x610 [ 69.337141][ C0] apic_timer_interrupt+0xf/0x20 [ 69.342236][ C0] [ 69.345154][ C0] RIP: 0010:native_safe_halt+0xe/0x10 [ 69.351864][ 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 [ 69.373248][ C0] RSP: 0018:ffffffff88e07c50 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff13 [ 69.382075][ C0] RAX: 1ffffffff11e5db7 RBX: 0000000000000000 RCX: 0000000000000000 [ 69.391008][ C0] RDX: dffffc0000000000 RSI: 0000000000000006 RDI: ffffffff88e7aa1c [ 69.399151][ C0] RBP: ffffffff88e07c80 R08: ffffffff88e7a180 R09: 0000000000000000 [ 69.407113][ C0] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000001 [ 69.415422][ C0] R13: 0000000000000000 R14: 0000000000000060 R15: 0000000000000001 [ 69.423492][ C0] ? default_idle+0x4e/0x360 [ 69.428151][ C0] default_enter_idle+0x71/0xf0 [ 69.433107][ C0] cpuidle_enter_state+0xef/0xfb0 [ 69.438145][ C0] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 69.444380][ C0] cpuidle_enter+0x4f/0xa0 [ 69.448966][ C0] do_idle+0x45f/0x6e0 [ 69.453049][ C0] ? arch_cpu_idle_exit+0x80/0x80 [ 69.458118][ C0] ? trace_hardirqs_on+0x30/0x240 [ 69.463268][ C0] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 69.469593][ C0] ? debug_smp_processor_id+0x3c/0x214 [ 69.475049][ C0] cpu_startup_entry+0x1b/0x20 [ 69.479883][ C0] rest_init+0x245/0x37b [ 69.484121][ C0] arch_call_rest_init+0xe/0x1b [ 69.488962][ C0] start_kernel+0x904/0x943 [ 69.493456][ C0] ? mem_encrypt_init+0xb/0xb [ 69.498300][ C0] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 69.504723][ C0] ? x86_family+0x41/0x50 [ 69.509071][ C0] ? __sanitizer_cov_trace_const_cmp1+0x1a/0x20