[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [ 55.541032][ T26] audit: type=1800 audit(1568162995.274:25): pid=8615 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="cron" dev="sda1" ino=2414 res=0 [ 55.580988][ T26] audit: type=1800 audit(1568162995.274:26): pid=8615 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="mcstrans" dev="sda1" ino=2457 res=0 [ 55.627458][ T26] audit: type=1800 audit(1568162995.274:27): pid=8615 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 '10.128.1.3' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 67.201054][ C0] [ 67.203407][ C0] ======================================================== [ 67.210657][ C0] WARNING: possible irq lock inversion dependency detected [ 67.217827][ C0] 5.3.0-rc6-next-20190830 #75 Not tainted [ 67.223523][ C0] -------------------------------------------------------- [ 67.230697][ C0] swapper/0/0 just changed the state of lock: [ 67.236885][ C0] ffff8880a0f01b58 (&(&ctx->ctx_lock)->rlock){..-.}, at: free_ioctx_users+0x2d/0x490 [ 67.246482][ C0] but this lock took another, SOFTIRQ-unsafe lock in the past: [ 67.254016][ C0] (&fiq->waitq){+.+.} [ 67.254024][ C0] [ 67.254024][ C0] [ 67.254024][ C0] and interrupts could create inverse lock ordering between them. [ 67.254024][ C0] [ 67.272350][ C0] [ 67.272350][ C0] other info that might help us debug this: [ 67.280382][ C0] Possible interrupt unsafe locking scenario: [ 67.280382][ C0] [ 67.288945][ C0] CPU0 CPU1 [ 67.294299][ C0] ---- ---- [ 67.299740][ C0] lock(&fiq->waitq); [ 67.303787][ C0] local_irq_disable(); [ 67.310516][ C0] lock(&(&ctx->ctx_lock)->rlock); [ 67.318209][ C0] lock(&fiq->waitq); [ 67.324771][ C0] [ 67.328207][ C0] lock(&(&ctx->ctx_lock)->rlock); [ 67.333552][ C0] [ 67.333552][ C0] *** DEADLOCK *** [ 67.333552][ C0] [ 67.341700][ C0] 2 locks held by swapper/0/0: [ 67.346463][ C0] #0: ffffffff88fa7e40 (rcu_callback){....}, at: rcu_core+0x60e/0x1560 [ 67.354779][ C0] #1: ffffffff88fa7e80 (rcu_read_lock_sched){....}, at: percpu_ref_switch_to_atomic_rcu+0x20e/0x570 [ 67.365720][ C0] [ 67.365720][ C0] the shortest dependencies between 2nd lock and 1st lock: [ 67.375080][ C0] -> (&fiq->waitq){+.+.} { [ 67.379561][ C0] HARDIRQ-ON-W at: [ 67.383616][ C0] lock_acquire+0x190/0x410 [ 67.389920][ C0] _raw_spin_lock+0x2f/0x40 [ 67.396223][ C0] flush_bg_queue+0x1f1/0x3b0 [ 67.405224][ C0] fuse_request_queue_background+0x2f8/0x5b0 [ 67.413001][ C0] fuse_request_send_background+0x58/0x110 [ 67.420606][ C0] cuse_channel_open+0x5c3/0x839 [ 67.427361][ C0] misc_open+0x395/0x4c0 [ 67.433959][ C0] chrdev_open+0x245/0x6b0 [ 67.440179][ C0] do_dentry_open+0x4df/0x1250 [ 67.446753][ C0] vfs_open+0xa0/0xd0 [ 67.452543][ C0] path_openat+0x10e9/0x46d0 [ 67.458930][ C0] do_filp_open+0x1a1/0x280 [ 67.465234][ C0] do_sys_open+0x3fe/0x5d0 [ 67.471448][ C0] __x64_sys_openat+0x9d/0x100 [ 67.478008][ C0] do_syscall_64+0xfa/0x760 [ 67.484397][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 67.492201][ C0] SOFTIRQ-ON-W at: [ 67.496248][ C0] lock_acquire+0x190/0x410 [ 67.502550][ C0] _raw_spin_lock+0x2f/0x40 [ 67.508849][ C0] flush_bg_queue+0x1f1/0x3b0 [ 67.515333][ C0] fuse_request_queue_background+0x2f8/0x5b0 [ 67.523120][ C0] fuse_request_send_background+0x58/0x110 [ 67.530721][ C0] cuse_channel_open+0x5c3/0x839 [ 67.537603][ C0] misc_open+0x395/0x4c0 [ 67.543769][ C0] chrdev_open+0x245/0x6b0 [ 67.550278][ C0] do_dentry_open+0x4df/0x1250 [ 67.557075][ C0] vfs_open+0xa0/0xd0 [ 67.562873][ C0] path_openat+0x10e9/0x46d0 [ 67.569264][ C0] do_filp_open+0x1a1/0x280 [ 67.575567][ C0] do_sys_open+0x3fe/0x5d0 [ 67.581782][ C0] __x64_sys_openat+0x9d/0x100 [ 67.588341][ C0] do_syscall_64+0xfa/0x760 [ 67.594650][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 67.602522][ C0] INITIAL USE at: [ 67.606495][ C0] lock_acquire+0x190/0x410 [ 67.612736][ C0] _raw_spin_lock+0x2f/0x40 [ 67.619087][ C0] flush_bg_queue+0x1f1/0x3b0 [ 67.625496][ C0] fuse_request_queue_background+0x2f8/0x5b0 [ 67.633471][ C0] fuse_request_send_background+0x58/0x110 [ 67.640991][ C0] cuse_channel_open+0x5c3/0x839 [ 67.647744][ C0] misc_open+0x395/0x4c0 [ 67.653703][ C0] chrdev_open+0x245/0x6b0 [ 67.659934][ C0] do_dentry_open+0x4df/0x1250 [ 67.666420][ C0] vfs_open+0xa0/0xd0 [ 67.672113][ C0] path_openat+0x10e9/0x46d0 [ 67.678412][ C0] do_filp_open+0x1a1/0x280 [ 67.684636][ C0] do_sys_open+0x3fe/0x5d0 [ 67.690761][ C0] __x64_sys_openat+0x9d/0x100 [ 67.697237][ C0] do_syscall_64+0xfa/0x760 [ 67.703455][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 67.711154][ C0] } [ 67.713741][ C0] ... key at: [] __key.44810+0x0/0x40 [ 67.721251][ C0] ... acquired at: [ 67.725130][ C0] _raw_spin_lock+0x2f/0x40 [ 67.729790][ C0] io_submit_one+0xefa/0x2ef0 [ 67.734795][ C0] __x64_sys_io_submit+0x1bd/0x570 [ 67.740086][ C0] do_syscall_64+0xfa/0x760 [ 67.744739][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 67.750779][ C0] [ 67.753089][ C0] -> (&(&ctx->ctx_lock)->rlock){..-.} { [ 67.758638][ C0] IN-SOFTIRQ-W at: [ 67.764048][ C0] lock_acquire+0x190/0x410 [ 67.770180][ C0] _raw_spin_lock_irq+0x60/0x80 [ 67.776668][ C0] free_ioctx_users+0x2d/0x490 [ 67.783057][ C0] percpu_ref_switch_to_atomic_rcu+0x4c0/0x570 [ 67.790859][ C0] rcu_core+0x581/0x1560 [ 67.796748][ C0] rcu_core_si+0x9/0x10 [ 67.802551][ C0] __do_softirq+0x262/0x98c [ 67.808690][ C0] irq_exit+0x19b/0x1e0 [ 67.814485][ C0] smp_apic_timer_interrupt+0x1a3/0x610 [ 67.821662][ C0] apic_timer_interrupt+0xf/0x20 [ 67.828225][ C0] native_safe_halt+0xe/0x10 [ 67.834966][ C0] default_enter_idle+0x71/0xf0 [ 67.841537][ C0] cpuidle_enter_state+0xef/0xfb0 [ 67.848181][ C0] cpuidle_enter+0x4f/0xa0 [ 67.854222][ C0] do_idle+0x45f/0x6e0 [ 67.859924][ C0] cpu_startup_entry+0x1b/0x20 [ 67.866313][ C0] rest_init+0x245/0x37b [ 67.872181][ C0] arch_call_rest_init+0xe/0x1b [ 67.878657][ C0] start_kernel+0x904/0x943 [ 67.884879][ C0] x86_64_start_reservations+0x29/0x2b [ 67.891975][ C0] x86_64_start_kernel+0x77/0x7b [ 67.898555][ C0] secondary_startup_64+0xa4/0xb0 [ 67.905216][ C0] INITIAL USE at: [ 67.909097][ C0] lock_acquire+0x190/0x410 [ 67.915154][ C0] _raw_spin_lock_irq+0x60/0x80 [ 67.921548][ C0] io_submit_one+0xeb5/0x2ef0 [ 67.927762][ C0] __x64_sys_io_submit+0x1bd/0x570 [ 67.934413][ C0] do_syscall_64+0xfa/0x760 [ 67.940518][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 67.947955][ C0] } [ 67.950494][ C0] ... key at: [] __key.54358+0x0/0x40 [ 67.957940][ C0] ... acquired at: [ 67.961731][ C0] mark_lock+0x517/0x1220 [ 67.966206][ C0] __lock_acquire+0x1e8e/0x4a00 [ 67.971203][ C0] lock_acquire+0x190/0x410 [ 67.975853][ C0] _raw_spin_lock_irq+0x60/0x80 [ 67.980847][ C0] free_ioctx_users+0x2d/0x490 [ 67.985759][ C0] percpu_ref_switch_to_atomic_rcu+0x4c0/0x570 [ 67.992075][ C0] rcu_core+0x581/0x1560 [ 67.996564][ C0] rcu_core_si+0x9/0x10 [ 68.000865][ C0] __do_softirq+0x262/0x98c [ 68.005514][ C0] irq_exit+0x19b/0x1e0 [ 68.009901][ C0] smp_apic_timer_interrupt+0x1a3/0x610 [ 68.015591][ C0] apic_timer_interrupt+0xf/0x20 [ 68.020677][ C0] native_safe_halt+0xe/0x10 [ 68.025414][ C0] default_enter_idle+0x71/0xf0 [ 68.030459][ C0] cpuidle_enter_state+0xef/0xfb0 [ 68.035639][ C0] cpuidle_enter+0x4f/0xa0 [ 68.040210][ C0] do_idle+0x45f/0x6e0 [ 68.044442][ C0] cpu_startup_entry+0x1b/0x20 [ 68.049441][ C0] rest_init+0x245/0x37b [ 68.053836][ C0] arch_call_rest_init+0xe/0x1b [ 68.058836][ C0] start_kernel+0x904/0x943 [ 68.063485][ C0] x86_64_start_reservations+0x29/0x2b [ 68.069223][ C0] x86_64_start_kernel+0x77/0x7b [ 68.074318][ C0] secondary_startup_64+0xa4/0xb0 [ 68.079488][ C0] [ 68.081853][ C0] [ 68.081853][ C0] stack backtrace: [ 68.087722][ C0] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.3.0-rc6-next-20190830 #75 [ 68.096026][ C0] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 68.106054][ C0] Call Trace: [ 68.109312][ C0] [ 68.112145][ C0] dump_stack+0x172/0x1f0 [ 68.116459][ C0] print_irq_inversion_bug.part.0+0x2e4/0x2f1 [ 68.122513][ C0] check_usage_forwards.cold+0x20/0x29 [ 68.127951][ C0] ? check_usage_backwards+0x330/0x330 [ 68.133396][ C0] ? save_trace+0x3e/0x8c0 [ 68.137789][ C0] mark_lock+0x517/0x1220 [ 68.142090][ C0] ? check_usage_backwards+0x330/0x330 [ 68.147522][ C0] __lock_acquire+0x1e8e/0x4a00 [ 68.152411][ C0] ? __kasan_check_read+0x11/0x20 [ 68.157434][ C0] ? mark_lock+0xc2/0x1220 [ 68.161977][ C0] ? mark_held_locks+0xf0/0xf0 [ 68.166726][ C0] lock_acquire+0x190/0x410 [ 68.171211][ C0] ? free_ioctx_users+0x2d/0x490 [ 68.176240][ C0] _raw_spin_lock_irq+0x60/0x80 [ 68.181079][ C0] ? free_ioctx_users+0x2d/0x490 [ 68.185990][ C0] free_ioctx_users+0x2d/0x490 [ 68.190741][ C0] ? rcu_dynticks_curr_cpu_in_eqs+0x54/0xb0 [ 68.196628][ C0] percpu_ref_switch_to_atomic_rcu+0x4c0/0x570 [ 68.202762][ C0] ? percpu_ref_exit+0xd0/0xd0 [ 68.207498][ C0] rcu_core+0x581/0x1560 [ 68.211718][ C0] ? __rcu_read_unlock+0x6b0/0x6b0 [ 68.216819][ C0] ? rcu_read_lock_sched_held+0x9c/0xd0 [ 68.222341][ C0] ? rcu_read_lock_any_held.part.0+0x50/0x50 [ 68.228318][ C0] ? run_rebalance_domains+0x227/0x2d0 [ 68.233852][ C0] rcu_core_si+0x9/0x10 [ 68.238002][ C0] __do_softirq+0x262/0x98c [ 68.242483][ C0] ? sched_clock_cpu+0x1b/0x1b0 [ 68.247313][ C0] irq_exit+0x19b/0x1e0 [ 68.251453][ C0] smp_apic_timer_interrupt+0x1a3/0x610 [ 68.256973][ C0] apic_timer_interrupt+0xf/0x20 [ 68.261889][ C0] [ 68.264802][ C0] RIP: 0010:native_safe_halt+0xe/0x10 [ 68.270157][ 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 [ 68.289841][ C0] RSP: 0018:ffffffff88e07c50 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff13 [ 68.298847][ C0] RAX: 1ffffffff11e5db7 RBX: 0000000000000000 RCX: 0000000000000000 [ 68.306798][ C0] RDX: dffffc0000000000 RSI: 0000000000000006 RDI: ffffffff88e7aa1c [ 68.314745][ C0] RBP: ffffffff88e07c80 R08: ffffffff88e7a180 R09: 0000000000000000 [ 68.322700][ C0] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000001 [ 68.330655][ C0] R13: 0000000000000000 R14: 0000000000000060 R15: 0000000000000001 [ 68.339054][ C0] ? default_idle+0x4e/0x360 [ 68.343739][ C0] default_enter_idle+0x71/0xf0 [ 68.348563][ C0] cpuidle_enter_state+0xef/0xfb0 [ 68.353636][ C0] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 68.359860][ C0] cpuidle_enter+0x4f/0xa0 [ 68.364250][ C0] do_idle+0x45f/0x6e0 [ 68.368293][ C0] ? arch_cpu_idle_exit+0x80/0x80 [ 68.373475][ C0] ? trace_hardirqs_on+0x30/0x240 [ 68.378476][ C0] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 68.384703][ C0] ? debug_smp_processor_id+0x3c/0x214 [ 68.390137][ C0] cpu_startup_entry+0x1b/0x20 [ 68.394877][ C0] rest_init+0x245/0x37b [ 68.399205][ C0] arch_call_rest_init+0xe/0x1b [ 68.404043][ C0]