[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [ 54.916598][ T26] audit: type=1800 audit(1567340364.152:25): pid=8525 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="cron" dev="sda1" ino=2414 res=0 [ 54.961851][ T26] audit: type=1800 audit(1567340364.152:26): pid=8525 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="mcstrans" dev="sda1" ino=2457 res=0 [ 55.001280][ T26] audit: type=1800 audit(1567340364.162:27): pid=8525 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 '10.128.0.39' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 66.211910][ C0] [ 66.214267][ C0] ======================================================== [ 66.221432][ C0] WARNING: possible irq lock inversion dependency detected [ 66.228605][ C0] 5.3.0-rc6-next-20190830 #75 Not tainted [ 66.234294][ C0] -------------------------------------------------------- [ 66.241466][ C0] swapper/0/0 just changed the state of lock: [ 66.247507][ C0] ffff8880917cdb58 (&(&ctx->ctx_lock)->rlock){..-.}, at: free_ioctx_users+0x2d/0x490 [ 66.256952][ C0] but this lock took another, SOFTIRQ-unsafe lock in the past: [ 66.264468][ C0] (&fiq->waitq){+.+.} [ 66.264476][ C0] [ 66.264476][ C0] [ 66.264476][ C0] and interrupts could create inverse lock ordering between them. [ 66.264476][ C0] [ 66.282827][ C0] [ 66.282827][ C0] other info that might help us debug this: [ 66.290893][ C0] Possible interrupt unsafe locking scenario: [ 66.290893][ C0] [ 66.299186][ C0] CPU0 CPU1 [ 66.304526][ C0] ---- ---- [ 66.309866][ C0] lock(&fiq->waitq); [ 66.313908][ C0] local_irq_disable(); [ 66.320635][ C0] lock(&(&ctx->ctx_lock)->rlock); [ 66.328320][ C0] lock(&fiq->waitq); [ 66.334879][ C0] [ 66.338306][ C0] lock(&(&ctx->ctx_lock)->rlock); [ 66.343667][ C0] [ 66.343667][ C0] *** DEADLOCK *** [ 66.343667][ C0] [ 66.351918][ C0] 2 locks held by swapper/0/0: [ 66.356652][ C0] #0: ffffffff88fa7e40 (rcu_callback){....}, at: rcu_core+0x60e/0x1560 [ 66.364984][ C0] #1: ffffffff88fa7e80 (rcu_read_lock_sched){....}, at: percpu_ref_switch_to_atomic_rcu+0x20e/0x570 [ 66.375818][ C0] [ 66.375818][ C0] the shortest dependencies between 2nd lock and 1st lock: [ 66.385165][ C0] -> (&fiq->waitq){+.+.} { [ 66.389645][ C0] HARDIRQ-ON-W at: [ 66.393708][ C0] lock_acquire+0x190/0x410 [ 66.400012][ C0] _raw_spin_lock+0x2f/0x40 [ 66.406317][ C0] flush_bg_queue+0x1f1/0x3b0 [ 66.412792][ C0] fuse_request_queue_background+0x2f8/0x5b0 [ 66.420581][ C0] fuse_request_send_background+0x58/0x110 [ 66.428199][ C0] cuse_channel_open+0x5c3/0x839 [ 66.434938][ C0] misc_open+0x395/0x4c0 [ 66.440986][ C0] chrdev_open+0x245/0x6b0 [ 66.447202][ C0] do_dentry_open+0x4df/0x1250 [ 66.453766][ C0] vfs_open+0xa0/0xd0 [ 66.459545][ C0] path_openat+0x10e9/0x46d0 [ 66.465935][ C0] do_filp_open+0x1a1/0x280 [ 66.472240][ C0] do_sys_open+0x3fe/0x5d0 [ 66.478539][ C0] __x64_sys_openat+0x9d/0x100 [ 66.485108][ C0] do_syscall_64+0xfa/0x760 [ 66.491415][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 66.500774][ C0] SOFTIRQ-ON-W at: [ 66.504826][ C0] lock_acquire+0x190/0x410 [ 66.511133][ C0] _raw_spin_lock+0x2f/0x40 [ 66.517542][ C0] flush_bg_queue+0x1f1/0x3b0 [ 66.525006][ C0] fuse_request_queue_background+0x2f8/0x5b0 [ 66.532792][ C0] fuse_request_send_background+0x58/0x110 [ 66.540408][ C0] cuse_channel_open+0x5c3/0x839 [ 66.547166][ C0] misc_open+0x395/0x4c0 [ 66.553214][ C0] chrdev_open+0x245/0x6b0 [ 66.559426][ C0] do_dentry_open+0x4df/0x1250 [ 66.566000][ C0] vfs_open+0xa0/0xd0 [ 66.571779][ C0] path_openat+0x10e9/0x46d0 [ 66.579296][ C0] do_filp_open+0x1a1/0x280 [ 66.585600][ C0] do_sys_open+0x3fe/0x5d0 [ 66.591819][ C0] __x64_sys_openat+0x9d/0x100 [ 66.598396][ C0] do_syscall_64+0xfa/0x760 [ 66.604717][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 66.612488][ C0] INITIAL USE at: [ 66.616469][ C0] lock_acquire+0x190/0x410 [ 66.622682][ C0] _raw_spin_lock+0x2f/0x40 [ 66.628893][ C0] flush_bg_queue+0x1f1/0x3b0 [ 66.635278][ C0] fuse_request_queue_background+0x2f8/0x5b0 [ 66.642965][ C0] fuse_request_send_background+0x58/0x110 [ 66.650476][ C0] cuse_channel_open+0x5c3/0x839 [ 66.657124][ C0] misc_open+0x395/0x4c0 [ 66.663078][ C0] chrdev_open+0x245/0x6b0 [ 66.669204][ C0] do_dentry_open+0x4df/0x1250 [ 66.675737][ C0] vfs_open+0xa0/0xd0 [ 66.681448][ C0] path_openat+0x10e9/0x46d0 [ 66.687748][ C0] do_filp_open+0x1a1/0x280 [ 66.693959][ C0] do_sys_open+0x3fe/0x5d0 [ 66.700084][ C0] __x64_sys_openat+0x9d/0x100 [ 66.706560][ C0] do_syscall_64+0xfa/0x760 [ 66.712778][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 66.720374][ C0] } [ 66.722947][ C0] ... key at: [] __key.44810+0x0/0x40 [ 66.730456][ C0] ... acquired at: [ 66.734351][ C0] _raw_spin_lock+0x2f/0x40 [ 66.739008][ C0] io_submit_one+0xefa/0x2ef0 [ 66.743838][ C0] __x64_sys_io_submit+0x1bd/0x570 [ 66.749098][ C0] do_syscall_64+0xfa/0x760 [ 66.753748][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 66.759793][ C0] [ 66.762093][ C0] -> (&(&ctx->ctx_lock)->rlock){..-.} { [ 66.767610][ C0] IN-SOFTIRQ-W at: [ 66.771570][ C0] lock_acquire+0x190/0x410 [ 66.777700][ C0] _raw_spin_lock_irq+0x60/0x80 [ 66.784191][ C0] free_ioctx_users+0x2d/0x490 [ 66.790601][ C0] percpu_ref_switch_to_atomic_rcu+0x4c0/0x570 [ 66.798381][ C0] rcu_core+0x581/0x1560 [ 66.804251][ C0] rcu_core_si+0x9/0x10 [ 66.810032][ C0] __do_softirq+0x262/0x98c [ 66.816167][ C0] irq_exit+0x19b/0x1e0 [ 66.822074][ C0] smp_apic_timer_interrupt+0x1a3/0x610 [ 66.829630][ C0] apic_timer_interrupt+0xf/0x20 [ 66.836195][ C0] native_safe_halt+0xe/0x10 [ 66.842429][ C0] default_enter_idle+0x71/0xf0 [ 66.848907][ C0] cpuidle_enter_state+0xef/0xfb0 [ 66.857423][ C0] cpuidle_enter+0x4f/0xa0 [ 66.864662][ C0] do_idle+0x45f/0x6e0 [ 66.870380][ C0] cpu_startup_entry+0x1b/0x20 [ 66.876772][ C0] rest_init+0x245/0x37b [ 66.882666][ C0] arch_call_rest_init+0xe/0x1b [ 66.889162][ C0] start_kernel+0x904/0x943 [ 66.895291][ C0] x86_64_start_reservations+0x29/0x2b [ 66.902419][ C0] x86_64_start_kernel+0x77/0x7b [ 66.909189][ C0] secondary_startup_64+0xa4/0xb0 [ 66.915834][ C0] INITIAL USE at: [ 66.919793][ C0] lock_acquire+0x190/0x410 [ 66.926030][ C0] _raw_spin_lock_irq+0x60/0x80 [ 66.932509][ C0] io_submit_one+0xeb5/0x2ef0 [ 66.938719][ C0] __x64_sys_io_submit+0x1bd/0x570 [ 66.945371][ C0] do_syscall_64+0xfa/0x760 [ 66.951415][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 66.958839][ C0] } [ 66.961326][ C0] ... key at: [] __key.54358+0x0/0x40 [ 66.968746][ C0] ... acquired at: [ 66.972534][ C0] mark_lock+0x517/0x1220 [ 66.977010][ C0] __lock_acquire+0x1e8e/0x4a00 [ 66.982009][ C0] lock_acquire+0x190/0x410 [ 66.986661][ C0] _raw_spin_lock_irq+0x60/0x80 [ 66.991672][ C0] free_ioctx_users+0x2d/0x490 [ 66.996586][ C0] percpu_ref_switch_to_atomic_rcu+0x4c0/0x570 [ 67.002888][ C0] rcu_core+0x581/0x1560 [ 67.007276][ C0] rcu_core_si+0x9/0x10 [ 67.011580][ C0] __do_softirq+0x262/0x98c [ 67.016246][ C0] irq_exit+0x19b/0x1e0 [ 67.020551][ C0] smp_apic_timer_interrupt+0x1a3/0x610 [ 67.026245][ C0] apic_timer_interrupt+0xf/0x20 [ 67.031331][ C0] native_safe_halt+0xe/0x10 [ 67.036087][ C0] default_enter_idle+0x71/0xf0 [ 67.041097][ C0] cpuidle_enter_state+0xef/0xfb0 [ 67.046283][ C0] cpuidle_enter+0x4f/0xa0 [ 67.050853][ C0] do_idle+0x45f/0x6e0 [ 67.055084][ C0] cpu_startup_entry+0x1b/0x20 [ 67.059993][ C0] rest_init+0x245/0x37b [ 67.064399][ C0] arch_call_rest_init+0xe/0x1b [ 67.069395][ C0] start_kernel+0x904/0x943 [ 67.074054][ C0] x86_64_start_reservations+0x29/0x2b [ 67.079672][ C0] x86_64_start_kernel+0x77/0x7b [ 67.084870][ C0] secondary_startup_64+0xa4/0xb0 [ 67.090039][ C0] [ 67.092339][ C0] [ 67.092339][ C0] stack backtrace: [ 67.098206][ C0] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.3.0-rc6-next-20190830 #75 [ 67.106501][ C0] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 67.116531][ C0] Call Trace: [ 67.119820][ C0] [ 67.122658][ C0] dump_stack+0x172/0x1f0 [ 67.126975][ C0] print_irq_inversion_bug.part.0+0x2e4/0x2f1 [ 67.133143][ C0] check_usage_forwards.cold+0x20/0x29 [ 67.138575][ C0] ? check_usage_backwards+0x330/0x330 [ 67.144010][ C0] ? save_trace+0x3e/0x8c0 [ 67.148402][ C0] mark_lock+0x517/0x1220 [ 67.152707][ C0] ? check_usage_backwards+0x330/0x330 [ 67.158139][ C0] __lock_acquire+0x1e8e/0x4a00 [ 67.163017][ C0] ? __kasan_check_read+0x11/0x20 [ 67.168044][ C0] ? mark_lock+0xc2/0x1220 [ 67.172439][ C0] ? mark_held_locks+0xf0/0xf0 [ 67.177182][ C0] lock_acquire+0x190/0x410 [ 67.181661][ C0] ? free_ioctx_users+0x2d/0x490 [ 67.186580][ C0] _raw_spin_lock_irq+0x60/0x80 [ 67.191404][ C0] ? free_ioctx_users+0x2d/0x490 [ 67.196315][ C0] free_ioctx_users+0x2d/0x490 [ 67.201057][ C0] ? rcu_dynticks_curr_cpu_in_eqs+0x54/0xb0 [ 67.207045][ C0] percpu_ref_switch_to_atomic_rcu+0x4c0/0x570 [ 67.213190][ C0] ? percpu_ref_exit+0xd0/0xd0 [ 67.217926][ C0] rcu_core+0x581/0x1560 [ 67.222156][ C0] ? __rcu_read_unlock+0x6b0/0x6b0 [ 67.227241][ C0] ? rcu_read_lock_sched_held+0x9c/0xd0 [ 67.232757][ C0] ? rcu_read_lock_any_held.part.0+0x50/0x50 [ 67.238709][ C0] ? run_rebalance_domains+0x227/0x2d0 [ 67.244144][ C0] rcu_core_si+0x9/0x10 [ 67.248272][ C0] __do_softirq+0x262/0x98c [ 67.252750][ C0] ? sched_clock_cpu+0x1b/0x1b0 [ 67.257578][ C0] irq_exit+0x19b/0x1e0 [ 67.261713][ C0] smp_apic_timer_interrupt+0x1a3/0x610 [ 67.267242][ C0] apic_timer_interrupt+0xf/0x20 [ 67.272149][ C0] [ 67.275063][ C0] RIP: 0010:native_safe_halt+0xe/0x10 [ 67.280414][ 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 [ 67.299992][ C0] RSP: 0018:ffffffff88e07c50 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff13 [ 67.308389][ C0] RAX: 1ffffffff11e5db7 RBX: 0000000000000000 RCX: 0000000000000000 [ 67.316336][ C0] RDX: dffffc0000000000 RSI: 0000000000000006 RDI: ffffffff88e7aa1c [ 67.324286][ C0] RBP: ffffffff88e07c80 R08: ffffffff88e7a180 R09: 0000000000000000 [ 67.332237][ C0] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000001 [ 67.340194][ C0] R13: 0000000000000000 R14: 0000000000000060 R15: 0000000000000001 [ 67.348170][ C0] ? default_idle+0x4e/0x360 [ 67.352738][ C0] default_enter_idle+0x71/0xf0 [ 67.357562][ C0] cpuidle_enter_state+0xef/0xfb0 [ 67.362563][ C0] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 67.368870][ C0] cpuidle_enter+0x4f/0xa0 [ 67.373265][ C0] do_idle+0x45f/0x6e0 [ 67.377327][ C0] ? arch_cpu_idle_exit+0x80/0x80 [ 67.382333][ C0] ? trace_hardirqs_on+0x30/0x240 [ 67.387331][ C0] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 67.393547][ C0] ? debug_smp_processor_id+0x3c/0x214 [ 67.398979][ C0] cpu_startup_entry+0x1b/0x20 [ 67.403723][ C0] rest_init+0x245/0x37b [ 67.407945][ C0] arch_call_rest_init+0xe/0x1b [ 67.412769][ C0] start_kernel+0x904/0x943