[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [ 54.182565][ T26] audit: type=1800 audit(1567318130.273:25): pid=8477 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="cron" dev="sda1" ino=2414 res=0 [ 54.204050][ T26] audit: type=1800 audit(1567318130.283:26): pid=8477 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="mcstrans" dev="sda1" ino=2457 res=0 [ 54.225721][ T26] audit: type=1800 audit(1567318130.283:27): pid=8477 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 '10.128.10.6' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 64.056264][ C1] [ 64.058642][ C1] ======================================================== [ 64.065807][ C1] WARNING: possible irq lock inversion dependency detected [ 64.072975][ C1] 5.3.0-rc6-next-20190830 #75 Not tainted [ 64.078661][ C1] -------------------------------------------------------- [ 64.085824][ C1] swapper/1/0 just changed the state of lock: [ 64.092001][ C1] ffff8880a4ae3b58 (&(&ctx->ctx_lock)->rlock){..-.}, at: free_ioctx_users+0x2d/0x490 [ 64.101444][ C1] but this lock took another, SOFTIRQ-unsafe lock in the past: [ 64.108952][ C1] (&fiq->waitq){+.+.} [ 64.108958][ C1] [ 64.108958][ C1] [ 64.108958][ C1] and interrupts could create inverse lock ordering between them. [ 64.108958][ C1] [ 64.127294][ C1] [ 64.127294][ C1] other info that might help us debug this: [ 64.135347][ C1] Possible interrupt unsafe locking scenario: [ 64.135347][ C1] [ 64.143635][ C1] CPU0 CPU1 [ 64.148972][ C1] ---- ---- [ 64.154309][ C1] lock(&fiq->waitq); [ 64.158346][ C1] local_irq_disable(); [ 64.166174][ C1] lock(&(&ctx->ctx_lock)->rlock); [ 64.173859][ C1] lock(&fiq->waitq); [ 64.180413][ C1] [ 64.183840][ C1] lock(&(&ctx->ctx_lock)->rlock); [ 64.189179][ C1] [ 64.189179][ C1] *** DEADLOCK *** [ 64.189179][ C1] [ 64.197295][ C1] 2 locks held by swapper/1/0: [ 64.202027][ C1] #0: ffffffff88fa7e40 (rcu_callback){....}, at: rcu_core+0x60e/0x1560 [ 64.210335][ C1] #1: ffffffff88fa7e80 (rcu_read_lock_sched){....}, at: percpu_ref_switch_to_atomic_rcu+0x20e/0x570 [ 64.221159][ C1] [ 64.221159][ C1] the shortest dependencies between 2nd lock and 1st lock: [ 64.230505][ C1] -> (&fiq->waitq){+.+.} { [ 64.234978][ C1] HARDIRQ-ON-W at: [ 64.239024][ C1] lock_acquire+0x190/0x410 [ 64.245328][ C1] _raw_spin_lock+0x2f/0x40 [ 64.251624][ C1] flush_bg_queue+0x1f1/0x3b0 [ 64.258102][ C1] fuse_request_queue_background+0x2f8/0x5b0 [ 64.265873][ C1] fuse_request_send_background+0x58/0x110 [ 64.273473][ C1] cuse_channel_open+0x5c3/0x839 [ 64.280204][ C1] misc_open+0x395/0x4c0 [ 64.286242][ C1] chrdev_open+0x245/0x6b0 [ 64.292452][ C1] do_dentry_open+0x4df/0x1250 [ 64.299007][ C1] vfs_open+0xa0/0xd0 [ 64.304785][ C1] path_openat+0x10e9/0x46d0 [ 64.311169][ C1] do_filp_open+0x1a1/0x280 [ 64.317473][ C1] do_sys_open+0x3fe/0x5d0 [ 64.323679][ C1] __x64_sys_openat+0x9d/0x100 [ 64.330239][ C1] do_syscall_64+0xfa/0x760 [ 64.336537][ C1] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 64.344218][ C1] SOFTIRQ-ON-W at: [ 64.348262][ C1] lock_acquire+0x190/0x410 [ 64.354560][ C1] _raw_spin_lock+0x2f/0x40 [ 64.360859][ C1] flush_bg_queue+0x1f1/0x3b0 [ 64.367344][ C1] fuse_request_queue_background+0x2f8/0x5b0 [ 64.375125][ C1] fuse_request_send_background+0x58/0x110 [ 64.382725][ C1] cuse_channel_open+0x5c3/0x839 [ 64.389470][ C1] misc_open+0x395/0x4c0 [ 64.395596][ C1] chrdev_open+0x245/0x6b0 [ 64.401806][ C1] do_dentry_open+0x4df/0x1250 [ 64.408382][ C1] vfs_open+0xa0/0xd0 [ 64.414163][ C1] path_openat+0x10e9/0x46d0 [ 64.420547][ C1] do_filp_open+0x1a1/0x280 [ 64.426845][ C1] do_sys_open+0x3fe/0x5d0 [ 64.433055][ C1] __x64_sys_openat+0x9d/0x100 [ 64.439615][ C1] do_syscall_64+0xfa/0x760 [ 64.445916][ C1] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 64.453596][ C1] INITIAL USE at: [ 64.457558][ C1] lock_acquire+0x190/0x410 [ 64.463766][ C1] _raw_spin_lock+0x2f/0x40 [ 64.469977][ C1] flush_bg_queue+0x1f1/0x3b0 [ 64.476362][ C1] fuse_request_queue_background+0x2f8/0x5b0 [ 64.484046][ C1] fuse_request_send_background+0x58/0x110 [ 64.491556][ C1] cuse_channel_open+0x5c3/0x839 [ 64.498205][ C1] misc_open+0x395/0x4c0 [ 64.504156][ C1] chrdev_open+0x245/0x6b0 [ 64.510286][ C1] do_dentry_open+0x4df/0x1250 [ 64.516774][ C1] vfs_open+0xa0/0xd0 [ 64.522484][ C1] path_openat+0x10e9/0x46d0 [ 64.528784][ C1] do_filp_open+0x1a1/0x280 [ 64.534993][ C1] do_sys_open+0x3fe/0x5d0 [ 64.541126][ C1] __x64_sys_openat+0x9d/0x100 [ 64.547614][ C1] do_syscall_64+0xfa/0x760 [ 64.553831][ C1] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 64.561425][ C1] } [ 64.563994][ C1] ... key at: [] __key.44810+0x0/0x40 [ 64.571501][ C1] ... acquired at: [ 64.575366][ C1] _raw_spin_lock+0x2f/0x40 [ 64.580287][ C1] io_submit_one+0xefa/0x2ef0 [ 64.585108][ C1] __x64_sys_io_submit+0x1bd/0x570 [ 64.590365][ C1] do_syscall_64+0xfa/0x760 [ 64.595013][ C1] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 64.601043][ C1] [ 64.603343][ C1] -> (&(&ctx->ctx_lock)->rlock){..-.} { [ 64.608861][ C1] IN-SOFTIRQ-W at: [ 64.612816][ C1] lock_acquire+0x190/0x410 [ 64.618941][ C1] _raw_spin_lock_irq+0x60/0x80 [ 64.625410][ C1] free_ioctx_users+0x2d/0x490 [ 64.631803][ C1] percpu_ref_switch_to_atomic_rcu+0x4c0/0x570 [ 64.639582][ C1] rcu_core+0x581/0x1560 [ 64.645443][ C1] rcu_core_si+0x9/0x10 [ 64.651222][ C1] __do_softirq+0x262/0x98c [ 64.657347][ C1] irq_exit+0x19b/0x1e0 [ 64.663124][ C1] smp_apic_timer_interrupt+0x1a3/0x610 [ 64.670393][ C1] apic_timer_interrupt+0xf/0x20 [ 64.676950][ C1] native_safe_halt+0xe/0x10 [ 64.683163][ C1] default_enter_idle+0x71/0xf0 [ 64.689632][ C1] cpuidle_enter_state+0xef/0xfb0 [ 64.696277][ C1] cpuidle_enter+0x4f/0xa0 [ 64.702315][ C1] do_idle+0x45f/0x6e0 [ 64.708019][ C1] cpu_startup_entry+0x1b/0x20 [ 64.714407][ C1] start_secondary+0x2f4/0x410 [ 64.720796][ C1] secondary_startup_64+0xa4/0xb0 [ 64.727437][ C1] INITIAL USE at: [ 64.731310][ C1] lock_acquire+0x190/0x410 [ 64.737374][ C1] _raw_spin_lock_irq+0x60/0x80 [ 64.743763][ C1] io_submit_one+0xeb5/0x2ef0 [ 64.749989][ C1] __x64_sys_io_submit+0x1bd/0x570 [ 64.756635][ C1] do_syscall_64+0xfa/0x760 [ 64.762672][ C1] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 64.770092][ C1] } [ 64.772576][ C1] ... key at: [] __key.54358+0x0/0x40 [ 64.779995][ C1] ... acquired at: [ 64.783778][ C1] mark_lock+0x517/0x1220 [ 64.788257][ C1] __lock_acquire+0x1e8e/0x4a00 [ 64.793255][ C1] lock_acquire+0x190/0x410 [ 64.797908][ C1] _raw_spin_lock_irq+0x60/0x80 [ 64.802917][ C1] free_ioctx_users+0x2d/0x490 [ 64.807829][ C1] percpu_ref_switch_to_atomic_rcu+0x4c0/0x570 [ 64.814128][ C1] rcu_core+0x581/0x1560 [ 64.818515][ C1] rcu_core_si+0x9/0x10 [ 64.822814][ C1] __do_softirq+0x262/0x98c [ 64.827460][ C1] irq_exit+0x19b/0x1e0 [ 64.831778][ C1] smp_apic_timer_interrupt+0x1a3/0x610 [ 64.837475][ C1] apic_timer_interrupt+0xf/0x20 [ 64.842554][ C1] native_safe_halt+0xe/0x10 [ 64.847305][ C1] default_enter_idle+0x71/0xf0 [ 64.852298][ C1] cpuidle_enter_state+0xef/0xfb0 [ 64.857465][ C1] cpuidle_enter+0x4f/0xa0 [ 64.862036][ C1] do_idle+0x45f/0x6e0 [ 64.866281][ C1] cpu_startup_entry+0x1b/0x20 [ 64.871205][ C1] start_secondary+0x2f4/0x410 [ 64.876119][ C1] secondary_startup_64+0xa4/0xb0 [ 64.881280][ C1] [ 64.883580][ C1] [ 64.883580][ C1] stack backtrace: [ 64.889446][ C1] CPU: 1 PID: 0 Comm: swapper/1 Not tainted 5.3.0-rc6-next-20190830 #75 [ 64.897749][ C1] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 64.907777][ C1] Call Trace: [ 64.911031][ C1] [ 64.913877][ C1] dump_stack+0x172/0x1f0 [ 64.918184][ C1] print_irq_inversion_bug.part.0+0x2e4/0x2f1 [ 64.924229][ C1] check_usage_forwards.cold+0x20/0x29 [ 64.929661][ C1] ? check_usage_backwards+0x330/0x330 [ 64.935089][ C1] ? save_trace+0x3e/0x8c0 [ 64.939569][ C1] mark_lock+0x517/0x1220 [ 64.943871][ C1] ? check_usage_backwards+0x330/0x330 [ 64.949307][ C1] __lock_acquire+0x1e8e/0x4a00 [ 64.954156][ C1] ? __kasan_check_read+0x11/0x20 [ 64.959153][ C1] ? mark_lock+0xc2/0x1220 [ 64.963542][ C1] ? mark_held_locks+0xf0/0xf0 [ 64.968279][ C1] lock_acquire+0x190/0x410 [ 64.972760][ C1] ? free_ioctx_users+0x2d/0x490 [ 64.977674][ C1] _raw_spin_lock_irq+0x60/0x80 [ 64.982496][ C1] ? free_ioctx_users+0x2d/0x490 [ 64.987412][ C1] free_ioctx_users+0x2d/0x490 [ 64.992168][ C1] ? rcu_dynticks_curr_cpu_in_eqs+0x54/0xb0 [ 64.998037][ C1] percpu_ref_switch_to_atomic_rcu+0x4c0/0x570 [ 65.004162][ C1] ? percpu_ref_exit+0xd0/0xd0 [ 65.008905][ C1] rcu_core+0x581/0x1560 [ 65.013120][ C1] ? __rcu_read_unlock+0x6b0/0x6b0 [ 65.018205][ C1] ? rcu_read_lock_sched_held+0x9c/0xd0 [ 65.023720][ C1] ? rcu_read_lock_any_held.part.0+0x50/0x50 [ 65.029673][ C1] ? run_rebalance_domains+0x227/0x2d0 [ 65.035103][ C1] rcu_core_si+0x9/0x10 [ 65.039242][ C1] __do_softirq+0x262/0x98c [ 65.043718][ C1] ? sched_clock_cpu+0x1b/0x1b0 [ 65.048546][ C1] irq_exit+0x19b/0x1e0 [ 65.052693][ C1] smp_apic_timer_interrupt+0x1a3/0x610 [ 65.058241][ C1] apic_timer_interrupt+0xf/0x20 [ 65.063145][ C1] [ 65.066162][ C1] RIP: 0010:native_safe_halt+0xe/0x10 [ 65.071509][ 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 [ 65.091102][ C1] RSP: 0018:ffff8880a98dfcd0 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff13 [ 65.099505][ C1] RAX: 1ffffffff11e5db7 RBX: 0000000000000000 RCX: 0000000000000000 [ 65.107453][ C1] RDX: dffffc0000000000 RSI: 0000000000000006 RDI: ffff8880a98d0bdc [ 65.115417][ C1] RBP: ffff8880a98dfd00 R08: ffff8880a98d0340 R09: 0000000000000000 [ 65.123365][ C1] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000001 [ 65.131308][ C1] R13: 0000000000000000 R14: 0000000000000060 R15: 0000000000000001 [ 65.139266][ C1] ? default_idle+0x4e/0x360 [ 65.143840][ C1] default_enter_idle+0x71/0xf0 [ 65.148668][ C1] cpuidle_enter_state+0xef/0xfb0 [ 65.153670][ C1] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 65.159890