[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [ 58.482018][ T26] audit: type=1800 audit(1568555382.209:25): pid=8731 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="cron" dev="sda1" ino=2414 res=0 [ 58.503704][ T26] audit: type=1800 audit(1568555382.219:26): pid=8731 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="mcstrans" dev="sda1" ino=2457 res=0 [ 58.524839][ T26] audit: type=1800 audit(1568555382.219:27): pid=8731 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 '10.128.0.92' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 69.923092][ C1] [ 69.925477][ C1] ======================================================== [ 69.932646][ C1] WARNING: possible irq lock inversion dependency detected [ 69.939819][ C1] 5.3.0-rc6-next-20190830 #75 Not tainted [ 69.945517][ C1] -------------------------------------------------------- [ 69.952695][ C1] swapper/1/0 just changed the state of lock: [ 69.958994][ C1] ffff88809e3c5b58 (&(&ctx->ctx_lock)->rlock){..-.}, at: free_ioctx_users+0x2d/0x490 [ 69.968435][ C1] but this lock took another, SOFTIRQ-unsafe lock in the past: [ 69.975943][ C1] (&fiq->waitq){+.+.} [ 69.975949][ C1] [ 69.975949][ C1] [ 69.975949][ C1] and interrupts could create inverse lock ordering between them. [ 69.975949][ C1] [ 69.994260][ C1] [ 69.994260][ C1] other info that might help us debug this: [ 70.002308][ C1] Possible interrupt unsafe locking scenario: [ 70.002308][ C1] [ 70.010598][ C1] CPU0 CPU1 [ 70.015946][ C1] ---- ---- [ 70.021285][ C1] lock(&fiq->waitq); [ 70.025325][ C1] local_irq_disable(); [ 70.032050][ C1] lock(&(&ctx->ctx_lock)->rlock); [ 70.039748][ C1] lock(&fiq->waitq); [ 70.046305][ C1] [ 70.049732][ C1] lock(&(&ctx->ctx_lock)->rlock); [ 70.055074][ C1] [ 70.055074][ C1] *** DEADLOCK *** [ 70.055074][ C1] [ 70.063193][ C1] 2 locks held by swapper/1/0: [ 70.067930][ C1] #0: ffffffff88fa7e40 (rcu_callback){....}, at: rcu_core+0x60e/0x1560 [ 70.076240][ C1] #1: ffffffff88fa7e80 (rcu_read_lock_sched){....}, at: percpu_ref_switch_to_atomic_rcu+0x20e/0x570 [ 70.087226][ C1] [ 70.087226][ C1] the shortest dependencies between 2nd lock and 1st lock: [ 70.096777][ C1] -> (&fiq->waitq){+.+.} { [ 70.101270][ C1] HARDIRQ-ON-W at: [ 70.105326][ C1] lock_acquire+0x190/0x410 [ 70.111633][ C1] _raw_spin_lock+0x2f/0x40 [ 70.117995][ C1] flush_bg_queue+0x1f1/0x3b0 [ 70.124481][ C1] fuse_request_queue_background+0x2f8/0x5b0 [ 70.132279][ C1] fuse_request_send_background+0x58/0x110 [ 70.139899][ C1] cuse_channel_open+0x5c3/0x839 [ 70.146670][ C1] misc_open+0x395/0x4c0 [ 70.152732][ C1] chrdev_open+0x245/0x6b0 [ 70.158981][ C1] do_dentry_open+0x4df/0x1250 [ 70.165558][ C1] vfs_open+0xa0/0xd0 [ 70.171350][ C1] path_openat+0x10e9/0x46d0 [ 70.177747][ C1] do_filp_open+0x1a1/0x280 [ 70.184053][ C1] do_sys_open+0x3fe/0x5d0 [ 70.190288][ C1] __x64_sys_openat+0x9d/0x100 [ 70.196878][ C1] do_syscall_64+0xfa/0x760 [ 70.203202][ C1] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 70.210904][ C1] SOFTIRQ-ON-W at: [ 70.214961][ C1] lock_acquire+0x190/0x410 [ 70.221279][ C1] _raw_spin_lock+0x2f/0x40 [ 70.227596][ C1] flush_bg_queue+0x1f1/0x3b0 [ 70.234131][ C1] fuse_request_queue_background+0x2f8/0x5b0 [ 70.241926][ C1] fuse_request_send_background+0x58/0x110 [ 70.249530][ C1] cuse_channel_open+0x5c3/0x839 [ 70.256353][ C1] misc_open+0x395/0x4c0 [ 70.262393][ C1] chrdev_open+0x245/0x6b0 [ 70.268610][ C1] do_dentry_open+0x4df/0x1250 [ 70.275168][ C1] vfs_open+0xa0/0xd0 [ 70.280944][ C1] path_openat+0x10e9/0x46d0 [ 70.287333][ C1] do_filp_open+0x1a1/0x280 [ 70.293647][ C1] do_sys_open+0x3fe/0x5d0 [ 70.299875][ C1] __x64_sys_openat+0x9d/0x100 [ 70.306439][ C1] do_syscall_64+0xfa/0x760 [ 70.312740][ C1] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 70.320426][ C1] INITIAL USE at: [ 70.324408][ C1] lock_acquire+0x190/0x410 [ 70.330622][ C1] _raw_spin_lock+0x2f/0x40 [ 70.336848][ C1] flush_bg_queue+0x1f1/0x3b0 [ 70.343243][ C1] fuse_request_queue_background+0x2f8/0x5b0 [ 70.350929][ C1] fuse_request_send_background+0x58/0x110 [ 70.358449][ C1] cuse_channel_open+0x5c3/0x839 [ 70.365108][ C1] misc_open+0x395/0x4c0 [ 70.371058][ C1] chrdev_open+0x245/0x6b0 [ 70.377182][ C1] do_dentry_open+0x4df/0x1250 [ 70.383651][ C1] vfs_open+0xa0/0xd0 [ 70.389355][ C1] path_openat+0x10e9/0x46d0 [ 70.395651][ C1] do_filp_open+0x1a1/0x280 [ 70.401866][ C1] do_sys_open+0x3fe/0x5d0 [ 70.407989][ C1] __x64_sys_openat+0x9d/0x100 [ 70.414460][ C1] do_syscall_64+0xfa/0x760 [ 70.420773][ C1] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 70.428381][ C1] } [ 70.430949][ C1] ... key at: [] __key.44810+0x0/0x40 [ 70.438456][ C1] ... acquired at: [ 70.442323][ C1] _raw_spin_lock+0x2f/0x40 [ 70.446985][ C1] io_submit_one+0xefa/0x2ef0 [ 70.451820][ C1] __x64_sys_io_submit+0x1bd/0x570 [ 70.457078][ C1] do_syscall_64+0xfa/0x760 [ 70.461726][ C1] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 70.467758][ C1] [ 70.470058][ C1] -> (&(&ctx->ctx_lock)->rlock){..-.} { [ 70.475749][ C1] IN-SOFTIRQ-W at: [ 70.479707][ C1] lock_acquire+0x190/0x410 [ 70.485835][ C1] _raw_spin_lock_irq+0x60/0x80 [ 70.492315][ C1] free_ioctx_users+0x2d/0x490 [ 70.498703][ C1] percpu_ref_switch_to_atomic_rcu+0x4c0/0x570 [ 70.506497][ C1] rcu_core+0x581/0x1560 [ 70.512367][ C1] rcu_core_si+0x9/0x10 [ 70.518171][ C1] __do_softirq+0x262/0x98c [ 70.524322][ C1] irq_exit+0x19b/0x1e0 [ 70.530169][ C1] smp_apic_timer_interrupt+0x1a3/0x610 [ 70.537444][ C1] apic_timer_interrupt+0xf/0x20 [ 70.544024][ C1] native_safe_halt+0xe/0x10 [ 70.550241][ C1] default_enter_idle+0x71/0xf0 [ 70.556716][ C1] cpuidle_enter_state+0xef/0xfb0 [ 70.563390][ C1] cpuidle_enter+0x4f/0xa0 [ 70.569722][ C1] do_idle+0x45f/0x6e0 [ 70.575418][ C1] cpu_startup_entry+0x1b/0x20 [ 70.581816][ C1] start_secondary+0x2f4/0x410 [ 70.588207][ C1] secondary_startup_64+0xa4/0xb0 [ 70.594852][ C1] INITIAL USE at: [ 70.598741][ C1] lock_acquire+0x190/0x410 [ 70.604782][ C1] _raw_spin_lock_irq+0x60/0x80 [ 70.611181][ C1] io_submit_one+0xeb5/0x2ef0 [ 70.617396][ C1] __x64_sys_io_submit+0x1bd/0x570 [ 70.624045][ C1] do_syscall_64+0xfa/0x760 [ 70.630117][ C1] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 70.637612][ C1] } [ 70.640102][ C1] ... key at: [] __key.54358+0x0/0x40 [ 70.647528][ C1] ... acquired at: [ 70.651320][ C1] mark_lock+0x517/0x1220 [ 70.655820][ C1] __lock_acquire+0x1e8e/0x4a00 [ 70.660945][ C1] lock_acquire+0x190/0x410 [ 70.665603][ C1] _raw_spin_lock_irq+0x60/0x80 [ 70.670609][ C1] free_ioctx_users+0x2d/0x490 [ 70.675578][ C1] percpu_ref_switch_to_atomic_rcu+0x4c0/0x570 [ 70.681897][ C1] rcu_core+0x581/0x1560 [ 70.686325][ C1] rcu_core_si+0x9/0x10 [ 70.690637][ C1] __do_softirq+0x262/0x98c [ 70.695299][ C1] irq_exit+0x19b/0x1e0 [ 70.699616][ C1] smp_apic_timer_interrupt+0x1a3/0x610 [ 70.705333][ C1] apic_timer_interrupt+0xf/0x20 [ 70.710553][ C1] native_safe_halt+0xe/0x10 [ 70.715305][ C1] default_enter_idle+0x71/0xf0 [ 70.720310][ C1] cpuidle_enter_state+0xef/0xfb0 [ 70.725483][ C1] cpuidle_enter+0x4f/0xa0 [ 70.730069][ C1] do_idle+0x45f/0x6e0 [ 70.734292][ C1] cpu_startup_entry+0x1b/0x20 [ 70.739212][ C1] start_secondary+0x2f4/0x410 [ 70.744126][ C1] secondary_startup_64+0xa4/0xb0 [ 70.749295][ C1] [ 70.751608][ C1] [ 70.751608][ C1] stack backtrace: [ 70.757475][ C1] CPU: 1 PID: 0 Comm: swapper/1 Not tainted 5.3.0-rc6-next-20190830 #75 [ 70.765768][ C1] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 70.775815][ C1] Call Trace: [ 70.779076][ C1] [ 70.781942][ C1] dump_stack+0x172/0x1f0 [ 70.786259][ C1] print_irq_inversion_bug.part.0+0x2e4/0x2f1 [ 70.792329][ C1] check_usage_forwards.cold+0x20/0x29 [ 70.797785][ C1] ? check_usage_backwards+0x330/0x330 [ 70.803226][ C1] ? save_trace+0x3e/0x8c0 [ 70.807619][ C1] mark_lock+0x517/0x1220 [ 70.811920][ C1] ? check_usage_backwards+0x330/0x330 [ 70.817365][ C1] __lock_acquire+0x1e8e/0x4a00 [ 70.822202][ C1] ? __kasan_check_read+0x11/0x20 [ 70.827207][ C1] ? mark_lock+0xc2/0x1220 [ 70.831613][ C1] ? mark_held_locks+0xf0/0xf0 [ 70.836379][ C1] lock_acquire+0x190/0x410 [ 70.840877][ C1] ? free_ioctx_users+0x2d/0x490 [ 70.845798][ C1] _raw_spin_lock_irq+0x60/0x80 [ 70.850646][ C1] ? free_ioctx_users+0x2d/0x490 [ 70.855560][ C1] free_ioctx_users+0x2d/0x490 [ 70.860307][ C1] ? rcu_dynticks_curr_cpu_in_eqs+0x54/0xb0 [ 70.866190][ C1] percpu_ref_switch_to_atomic_rcu+0x4c0/0x570 [ 70.872322][ C1] ? percpu_ref_exit+0xd0/0xd0 [ 70.877064][ C1] rcu_core+0x581/0x1560 [ 70.881282][ C1] ? __rcu_read_unlock+0x6b0/0x6b0 [ 70.886369][ C1] ? rcu_read_lock_sched_held+0x9c/0xd0 [ 70.891933][ C1] ? rcu_read_lock_any_held.part.0+0x50/0x50 [ 70.897915][ C1] ? run_rebalance_domains+0x227/0x2d0 [ 70.903351][ C1] rcu_core_si+0x9/0x10 [ 70.907488][ C1] __do_softirq+0x262/0x98c [ 70.911974][ C1] ? sched_clock_cpu+0x1b/0x1b0 [ 70.916816][ C1] irq_exit+0x19b/0x1e0 [ 70.920953][ C1] smp_apic_timer_interrupt+0x1a3/0x610 [ 70.926490][ C1] apic_timer_interrupt+0xf/0x20 [ 70.931418][ C1] [ 70.934356][ C1] RIP: 0010:native_safe_halt+0xe/0x10 [ 70.939765][ C1] 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 [ 70.959358][ C1] RSP: 0018:ffff8880a98dfcd0 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff13 [ 70.967760][ C1] RAX: 1ffffffff11e5db7 RBX: 0000000000000000 RCX: 0000000000000000 [ 70.975719][ C1] RDX: dffffc0000000000 RSI: 0000000000000006 RDI: ffff8880a98d0bdc [ 70.983703][ C1] RBP: ffff8880a98dfd00 R08: ffff8880a98d0340 R09: 0000000000000000 [ 70.991678][ C1] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000001 [ 70.999627][ C1] R13: 0000000000000000 R14: 0000000000000060 R15: 0000000000000001 [ 71.007599][ C1] ? default_idle+0x4e/0x360 [ 71.012170][ C1] default_enter_idle+0x71/0xf0 [ 71.017002][ C1] cpuidle_enter_state+0xef/0xfb0 [ 71.022009][ C1] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20