[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [ 55.382142][ T26] audit: type=1800 audit(1567341736.399:25): pid=8465 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="cron" dev="sda1" ino=2414 res=0 [ 55.417556][ T26] audit: type=1800 audit(1567341736.399:26): pid=8465 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="mcstrans" dev="sda1" ino=2457 res=0 [ 55.474811][ T26] audit: type=1800 audit(1567341736.409:27): pid=8465 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 '10.128.0.142' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 63.277617][ C0] [ 63.279970][ C0] ======================================================== [ 63.287158][ C0] WARNING: possible irq lock inversion dependency detected [ 63.294343][ C0] 5.3.0-rc6-next-20190830 #75 Not tainted [ 63.300039][ C0] -------------------------------------------------------- [ 63.307204][ C0] swapper/0/0 just changed the state of lock: [ 63.313239][ C0] ffff88809481bb58 (&(&ctx->ctx_lock)->rlock){..-.}, at: free_ioctx_users+0x2d/0x490 [ 63.322674][ C0] but this lock took another, SOFTIRQ-unsafe lock in the past: [ 63.330182][ C0] (&fiq->waitq){+.+.} [ 63.330188][ C0] [ 63.330188][ C0] [ 63.330188][ C0] and interrupts could create inverse lock ordering between them. [ 63.330188][ C0] [ 63.348497][ C0] [ 63.348497][ C0] other info that might help us debug this: [ 63.356525][ C0] Possible interrupt unsafe locking scenario: [ 63.356525][ C0] [ 63.364810][ C0] CPU0 CPU1 [ 63.370145][ C0] ---- ---- [ 63.375493][ C0] lock(&fiq->waitq); [ 63.379526][ C0] local_irq_disable(); [ 63.386249][ C0] lock(&(&ctx->ctx_lock)->rlock); [ 63.393930][ C0] lock(&fiq->waitq); [ 63.400484][ C0] [ 63.403915][ C0] lock(&(&ctx->ctx_lock)->rlock); [ 63.409253][ C0] [ 63.409253][ C0] *** DEADLOCK *** [ 63.409253][ C0] [ 63.417381][ C0] 2 locks held by swapper/0/0: [ 63.424245][ C0] #0: ffffffff88fa7e40 (rcu_callback){....}, at: rcu_core+0x60e/0x1560 [ 63.432559][ C0] #1: ffffffff88fa7e80 (rcu_read_lock_sched){....}, at: percpu_ref_switch_to_atomic_rcu+0x20e/0x570 [ 63.443382][ C0] [ 63.443382][ C0] the shortest dependencies between 2nd lock and 1st lock: [ 63.452736][ C0] -> (&fiq->waitq){+.+.} { [ 63.457209][ C0] HARDIRQ-ON-W at: [ 63.461253][ C0] lock_acquire+0x190/0x410 [ 63.467553][ C0] _raw_spin_lock+0x2f/0x40 [ 63.473866][ C0] flush_bg_queue+0x1f1/0x3b0 [ 63.480339][ C0] fuse_request_queue_background+0x2f8/0x5b0 [ 63.488113][ C0] fuse_request_send_background+0x58/0x110 [ 63.495711][ C0] cuse_channel_open+0x5c3/0x839 [ 63.502458][ C0] misc_open+0x395/0x4c0 [ 63.508501][ C0] chrdev_open+0x245/0x6b0 [ 63.514709][ C0] do_dentry_open+0x4df/0x1250 [ 63.521278][ C0] vfs_open+0xa0/0xd0 [ 63.527065][ C0] path_openat+0x10e9/0x46d0 [ 63.533449][ C0] do_filp_open+0x1a1/0x280 [ 63.539747][ C0] do_sys_open+0x3fe/0x5d0 [ 63.545967][ C0] __x64_sys_openat+0x9d/0x100 [ 63.552527][ C0] do_syscall_64+0xfa/0x760 [ 63.558823][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 63.566502][ C0] SOFTIRQ-ON-W at: [ 63.570546][ C0] lock_acquire+0x190/0x410 [ 63.576841][ C0] _raw_spin_lock+0x2f/0x40 [ 63.583133][ C0] flush_bg_queue+0x1f1/0x3b0 [ 63.589618][ C0] fuse_request_queue_background+0x2f8/0x5b0 [ 63.597404][ C0] fuse_request_send_background+0x58/0x110 [ 63.605002][ C0] cuse_channel_open+0x5c3/0x839 [ 63.611731][ C0] misc_open+0x395/0x4c0 [ 63.617771][ C0] chrdev_open+0x245/0x6b0 [ 63.623994][ C0] do_dentry_open+0x4df/0x1250 [ 63.630552][ C0] vfs_open+0xa0/0xd0 [ 63.636327][ C0] path_openat+0x10e9/0x46d0 [ 63.642724][ C0] do_filp_open+0x1a1/0x280 [ 63.649023][ C0] do_sys_open+0x3fe/0x5d0 [ 63.655232][ C0] __x64_sys_openat+0x9d/0x100 [ 63.661788][ C0] do_syscall_64+0xfa/0x760 [ 63.668085][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 63.675763][ C0] INITIAL USE at: [ 63.679716][ C0] lock_acquire+0x190/0x410 [ 63.685926][ C0] _raw_spin_lock+0x2f/0x40 [ 63.692157][ C0] flush_bg_queue+0x1f1/0x3b0 [ 63.698545][ C0] fuse_request_queue_background+0x2f8/0x5b0 [ 63.706242][ C0] fuse_request_send_background+0x58/0x110 [ 63.713751][ C0] cuse_channel_open+0x5c3/0x839 [ 63.720407][ C0] misc_open+0x395/0x4c0 [ 63.726368][ C0] chrdev_open+0x245/0x6b0 [ 63.732491][ C0] do_dentry_open+0x4df/0x1250 [ 63.738959][ C0] vfs_open+0xa0/0xd0 [ 63.744659][ C0] path_openat+0x10e9/0x46d0 [ 63.750956][ C0] do_filp_open+0x1a1/0x280 [ 63.757163][ C0] do_sys_open+0x3fe/0x5d0 [ 63.763289][ C0] __x64_sys_openat+0x9d/0x100 [ 63.769758][ C0] do_syscall_64+0xfa/0x760 [ 63.775970][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 63.783560][ C0] } [ 63.786124][ C0] ... key at: [] __key.44810+0x0/0x40 [ 63.793629][ C0] ... acquired at: [ 63.797514][ C0] _raw_spin_lock+0x2f/0x40 [ 63.802164][ C0] io_submit_one+0xefa/0x2ef0 [ 63.806982][ C0] __x64_sys_io_submit+0x1bd/0x570 [ 63.812247][ C0] do_syscall_64+0xfa/0x760 [ 63.816894][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 63.822949][ C0] [ 63.825271][ C0] -> (&(&ctx->ctx_lock)->rlock){..-.} { [ 63.830788][ C0] IN-SOFTIRQ-W at: [ 63.834743][ C0] lock_acquire+0x190/0x410 [ 63.840863][ C0] _raw_spin_lock_irq+0x60/0x80 [ 63.847330][ C0] free_ioctx_users+0x2d/0x490 [ 63.853721][ C0] percpu_ref_switch_to_atomic_rcu+0x4c0/0x570 [ 63.861492][ C0] rcu_core+0x581/0x1560 [ 63.867354][ C0] rcu_core_si+0x9/0x10 [ 63.873129][ C0] __do_softirq+0x262/0x98c [ 63.879249][ C0] irq_exit+0x19b/0x1e0 [ 63.885021][ C0] smp_apic_timer_interrupt+0x1a3/0x610 [ 63.892187][ C0] apic_timer_interrupt+0xf/0x20 [ 63.898744][ C0] native_safe_halt+0xe/0x10 [ 63.904965][ C0] default_enter_idle+0x71/0xf0 [ 63.911440][ C0] cpuidle_enter_state+0xef/0xfb0 [ 63.918081][ C0] cpuidle_enter+0x4f/0xa0 [ 63.924115][ C0] do_idle+0x45f/0x6e0 [ 63.929802][ C0] cpu_startup_entry+0x1b/0x20 [ 63.936183][ C0] rest_init+0x245/0x37b [ 63.942050][ C0] arch_call_rest_init+0xe/0x1b [ 63.948522][ C0] start_kernel+0x904/0x943 [ 63.954644][ C0] x86_64_start_reservations+0x29/0x2b [ 63.961736][ C0] x86_64_start_kernel+0x77/0x7b [ 63.968296][ C0] secondary_startup_64+0xa4/0xb0 [ 63.974937][ C0] INITIAL USE at: [ 63.978805][ C0] lock_acquire+0x190/0x410 [ 63.984842][ C0] _raw_spin_lock_irq+0x60/0x80 [ 63.991241][ C0] io_submit_one+0xeb5/0x2ef0 [ 63.997469][ C0] __x64_sys_io_submit+0x1bd/0x570 [ 64.004113][ C0] do_syscall_64+0xfa/0x760 [ 64.010152][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 64.017573][ C0] } [ 64.020066][ C0] ... key at: [] __key.54358+0x0/0x40 [ 64.027486][ C0] ... acquired at: [ 64.031271][ C0] mark_lock+0x517/0x1220 [ 64.035745][ C0] __lock_acquire+0x1e8e/0x4a00 [ 64.040738][ C0] lock_acquire+0x190/0x410 [ 64.045384][ C0] _raw_spin_lock_irq+0x60/0x80 [ 64.050381][ C0] free_ioctx_users+0x2d/0x490 [ 64.055287][ C0] percpu_ref_switch_to_atomic_rcu+0x4c0/0x570 [ 64.061592][ C0] rcu_core+0x581/0x1560 [ 64.065977][ C0] rcu_core_si+0x9/0x10 [ 64.070280][ C0] __do_softirq+0x262/0x98c [ 64.074930][ C0] irq_exit+0x19b/0x1e0 [ 64.079228][ C0] smp_apic_timer_interrupt+0x1a3/0x610 [ 64.084913][ C0] apic_timer_interrupt+0xf/0x20 [ 64.089992][ C0] native_safe_halt+0xe/0x10 [ 64.094729][ C0] default_enter_idle+0x71/0xf0 [ 64.099724][ C0] cpuidle_enter_state+0xef/0xfb0 [ 64.104889][ C0] cpuidle_enter+0x4f/0xa0 [ 64.109450][ C0] do_idle+0x45f/0x6e0 [ 64.113659][ C0] cpu_startup_entry+0x1b/0x20 [ 64.118565][ C0] rest_init+0x245/0x37b [ 64.122952][ C0] arch_call_rest_init+0xe/0x1b [ 64.127955][ C0] start_kernel+0x904/0x943 [ 64.132611][ C0] x86_64_start_reservations+0x29/0x2b [ 64.138214][ C0] x86_64_start_kernel+0x77/0x7b [ 64.143292][ C0] secondary_startup_64+0xa4/0xb0 [ 64.148456][ C0] [ 64.150760][ C0] [ 64.150760][ C0] stack backtrace: [ 64.156628][ C0] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.3.0-rc6-next-20190830 #75 [ 64.164916][ C0] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 64.174959][ C0] Call Trace: [ 64.178216][ C0] [ 64.181045][ C0] dump_stack+0x172/0x1f0 [ 64.185349][ C0] print_irq_inversion_bug.part.0+0x2e4/0x2f1 [ 64.191386][ C0] check_usage_forwards.cold+0x20/0x29 [ 64.196816][ C0] ? check_usage_backwards+0x330/0x330 [ 64.202245][ C0] ? save_trace+0x3e/0x8c0 [ 64.206718][ C0] mark_lock+0x517/0x1220 [ 64.211018][ C0] ? check_usage_backwards+0x330/0x330 [ 64.216446][ C0] __lock_acquire+0x1e8e/0x4a00 [ 64.221270][ C0] ? __kasan_check_read+0x11/0x20 [ 64.226264][ C0] ? mark_lock+0xc2/0x1220 [ 64.230653][ C0] ? mark_held_locks+0xf0/0xf0 [ 64.235404][ C0] lock_acquire+0x190/0x410 [ 64.239876][ C0] ? free_ioctx_users+0x2d/0x490 [ 64.244787][ C0] _raw_spin_lock_irq+0x60/0x80 [ 64.249611][ C0] ? free_ioctx_users+0x2d/0x490 [ 64.255852][ C0] free_ioctx_users+0x2d/0x490 [ 64.260588][ C0] ? rcu_dynticks_curr_cpu_in_eqs+0x54/0xb0 [ 64.266453][ C0] percpu_ref_switch_to_atomic_rcu+0x4c0/0x570 [ 64.272590][ C0] ? percpu_ref_exit+0xd0/0xd0 [ 64.277325][ C0] rcu_core+0x581/0x1560 [ 64.281537][ C0] ? __rcu_read_unlock+0x6b0/0x6b0 [ 64.286627][ C0] ? rcu_read_lock_sched_held+0x9c/0xd0 [ 64.292159][ C0] ? rcu_read_lock_any_held.part.0+0x50/0x50 [ 64.298121][ C0] ? run_rebalance_domains+0x227/0x2d0 [ 64.303549][ C0] rcu_core_si+0x9/0x10 [ 64.307692][ C0] __do_softirq+0x262/0x98c [ 64.312176][ C0] ? sched_clock_cpu+0x1b/0x1b0 [ 64.317013][ C0] irq_exit+0x19b/0x1e0 [ 64.321137][ C0] smp_apic_timer_interrupt+0x1a3/0x610 [ 64.326656][ C0] apic_timer_interrupt+0xf/0x20 [ 64.331562][ C0] [ 64.334476][ C0] RIP: 0010:native_safe_halt+0xe/0x10 [ 64.339991][ 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 [ 64.359743][ C0] RSP: 0018:ffffffff88e07c50 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff13 [ 64.368128][ C0] RAX: 1ffffffff11e5db7 RBX: 0000000000000000 RCX: 0000000000000000 [ 64.376075][ C0] RDX: dffffc0000000000 RSI: 0000000000000006 RDI: ffffffff88e7aa1c [ 64.384017][ C0] RBP: ffffffff88e07c80 R08: ffffffff88e7a180 R09: 0000000000000000 [ 64.391973][ C0] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000001 [ 64.399917][ C0] R13: 0000000000000000 R14: 0000000000000060 R15: 0000000000000001 [ 64.407890][ C0] ? default_idle+0x4e/0x360 [ 64.412473][ C0] default_enter_idle+0x71/0xf0 [ 64.417295][ C0] cpuidle_enter_state+0xef/0xfb0 [ 64.422293][ C0] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 64.428506][ C0] cpuidle_enter+0x4f/0xa0 [ 64.432909][ C0] do_idle+0x45f/0x6e0 [ 64.436950][ C0] ? arch_cpu_idle_exit+0x80/0x80 [ 64.441944][ C0] ? trace_hardirqs_on+0x30/0x240 [ 64.446940][ C0] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 64.453179][ C0] ? debug_smp_processor_id+0x3c/0x214 [ 64.458611][ C0] cpu_startup_entry+0x1b/0x20 [ 64.463343][ C0] rest_init+0x245/0x37b [ 64.467606][ C0] arch_call_rest_init+0xe/0x1b [ 64.472429][ C0] start_kernel+0x904/0x943 [ 64.476905][ C0] ? mem_encrypt_init+0xb/0xb [ 64.481554]