[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [ 56.012941][ T26] audit: type=1800 audit(1568257066.471:25): pid=8554 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="cron" dev="sda1" ino=2414 res=0 [ 56.053442][ T26] audit: type=1800 audit(1568257066.471:26): pid=8554 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="mcstrans" dev="sda1" ino=2457 res=0 [ 56.103151][ T26] audit: type=1800 audit(1568257066.471:27): pid=8554 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 '10.128.0.231' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 73.123267][ C1] [ 73.125730][ C1] ======================================================== [ 73.132894][ C1] WARNING: possible irq lock inversion dependency detected [ 73.140074][ C1] 5.3.0-rc6-next-20190830 #75 Not tainted [ 73.145763][ C1] -------------------------------------------------------- [ 73.152934][ C1] swapper/1/0 just changed the state of lock: [ 73.158987][ C1] ffff888096d31b58 (&(&ctx->ctx_lock)->rlock){..-.}, at: free_ioctx_users+0x2d/0x490 [ 73.168450][ C1] but this lock took another, SOFTIRQ-unsafe lock in the past: [ 73.179864][ C1] (&fiq->waitq){+.+.} [ 73.179870][ C1] [ 73.179870][ C1] [ 73.179870][ C1] and interrupts could create inverse lock ordering between them. [ 73.179870][ C1] [ 73.198186][ C1] [ 73.198186][ C1] other info that might help us debug this: [ 73.206215][ C1] Possible interrupt unsafe locking scenario: [ 73.206215][ C1] [ 73.214521][ C1] CPU0 CPU1 [ 73.219862][ C1] ---- ---- [ 73.225199][ C1] lock(&fiq->waitq); [ 73.229239][ C1] local_irq_disable(); [ 73.236948][ C1] lock(&(&ctx->ctx_lock)->rlock); [ 73.244632][ C1] lock(&fiq->waitq); [ 73.251188][ C1] [ 73.254617][ C1] lock(&(&ctx->ctx_lock)->rlock); [ 73.259959][ C1] [ 73.259959][ C1] *** DEADLOCK *** [ 73.259959][ C1] [ 73.268251][ C1] 2 locks held by swapper/1/0: [ 73.272980][ C1] #0: ffffffff88fa7e40 (rcu_callback){....}, at: rcu_core+0x60e/0x1560 [ 73.281308][ C1] #1: ffffffff88fa7e80 (rcu_read_lock_sched){....}, at: percpu_ref_switch_to_atomic_rcu+0x20e/0x570 [ 73.292156][ C1] [ 73.292156][ C1] the shortest dependencies between 2nd lock and 1st lock: [ 73.301553][ C1] -> (&fiq->waitq){+.+.} { [ 73.306037][ C1] HARDIRQ-ON-W at: [ 73.310092][ C1] lock_acquire+0x190/0x410 [ 73.316416][ C1] _raw_spin_lock+0x2f/0x40 [ 73.322753][ C1] flush_bg_queue+0x1f1/0x3b0 [ 73.329247][ C1] fuse_request_queue_background+0x2f8/0x5b0 [ 73.337024][ C1] fuse_request_send_background+0x58/0x110 [ 73.344626][ C1] cuse_channel_open+0x5c3/0x839 [ 73.351370][ C1] misc_open+0x395/0x4c0 [ 73.357410][ C1] chrdev_open+0x245/0x6b0 [ 73.363901][ C1] do_dentry_open+0x4df/0x1250 [ 73.370459][ C1] vfs_open+0xa0/0xd0 [ 73.376244][ C1] path_openat+0x10e9/0x46d0 [ 73.382630][ C1] do_filp_open+0x1a1/0x280 [ 73.388928][ C1] do_sys_open+0x3fe/0x5d0 [ 73.395153][ C1] __x64_sys_openat+0x9d/0x100 [ 73.401726][ C1] do_syscall_64+0xfa/0x760 [ 73.408027][ C1] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 73.415722][ C1] SOFTIRQ-ON-W at: [ 73.419769][ C1] lock_acquire+0x190/0x410 [ 73.426082][ C1] _raw_spin_lock+0x2f/0x40 [ 73.432395][ C1] flush_bg_queue+0x1f1/0x3b0 [ 73.438883][ C1] fuse_request_queue_background+0x2f8/0x5b0 [ 73.446662][ C1] fuse_request_send_background+0x58/0x110 [ 73.454275][ C1] cuse_channel_open+0x5c3/0x839 [ 73.461019][ C1] misc_open+0x395/0x4c0 [ 73.467072][ C1] chrdev_open+0x245/0x6b0 [ 73.473289][ C1] do_dentry_open+0x4df/0x1250 [ 73.479851][ C1] vfs_open+0xa0/0xd0 [ 73.485630][ C1] path_openat+0x10e9/0x46d0 [ 73.492015][ C1] do_filp_open+0x1a1/0x280 [ 73.498316][ C1] do_sys_open+0x3fe/0x5d0 [ 73.504534][ C1] __x64_sys_openat+0x9d/0x100 [ 73.511096][ C1] do_syscall_64+0xfa/0x760 [ 73.517421][ C1] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 73.525108][ C1] INITIAL USE at: [ 73.529076][ C1] lock_acquire+0x190/0x410 [ 73.535293][ C1] _raw_spin_lock+0x2f/0x40 [ 73.541506][ C1] flush_bg_queue+0x1f1/0x3b0 [ 73.547889][ C1] fuse_request_queue_background+0x2f8/0x5b0 [ 73.555577][ C1] fuse_request_send_background+0x58/0x110 [ 73.563438][ C1] cuse_channel_open+0x5c3/0x839 [ 73.570083][ C1] misc_open+0x395/0x4c0 [ 73.576040][ C1] chrdev_open+0x245/0x6b0 [ 73.582168][ C1] do_dentry_open+0x4df/0x1250 [ 73.588643][ C1] vfs_open+0xa0/0xd0 [ 73.594341][ C1] path_openat+0x10e9/0x46d0 [ 73.600642][ C1] do_filp_open+0x1a1/0x280 [ 73.606866][ C1] do_sys_open+0x3fe/0x5d0 [ 73.613015][ C1] __x64_sys_openat+0x9d/0x100 [ 73.619496][ C1] do_syscall_64+0xfa/0x760 [ 73.625711][ C1] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 73.633306][ C1] } [ 73.635874][ C1] ... key at: [] __key.44810+0x0/0x40 [ 73.643384][ C1] ... acquired at: [ 73.647254][ C1] _raw_spin_lock+0x2f/0x40 [ 73.651915][ C1] io_submit_one+0xefa/0x2ef0 [ 73.656761][ C1] __x64_sys_io_submit+0x1bd/0x570 [ 73.662016][ C1] do_syscall_64+0xfa/0x760 [ 73.666665][ C1] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 73.672705][ C1] [ 73.675009][ C1] -> (&(&ctx->ctx_lock)->rlock){..-.} { [ 73.680661][ C1] IN-SOFTIRQ-W at: [ 73.684653][ C1] lock_acquire+0x190/0x410 [ 73.690787][ C1] _raw_spin_lock_irq+0x60/0x80 [ 73.697267][ C1] free_ioctx_users+0x2d/0x490 [ 73.703658][ C1] percpu_ref_switch_to_atomic_rcu+0x4c0/0x570 [ 73.711435][ C1] rcu_core+0x581/0x1560 [ 73.717302][ C1] rcu_core_si+0x9/0x10 [ 73.723098][ C1] __do_softirq+0x262/0x98c [ 73.729237][ C1] irq_exit+0x19b/0x1e0 [ 73.735018][ C1] smp_apic_timer_interrupt+0x1a3/0x610 [ 73.742184][ C1] apic_timer_interrupt+0xf/0x20 [ 73.748746][ C1] native_safe_halt+0xe/0x10 [ 73.754981][ C1] default_enter_idle+0x71/0xf0 [ 73.761466][ C1] cpuidle_enter_state+0xef/0xfb0 [ 73.768118][ C1] cpuidle_enter+0x4f/0xa0 [ 73.774156][ C1] do_idle+0x45f/0x6e0 [ 73.779849][ C1] cpu_startup_entry+0x1b/0x20 [ 73.786248][ C1] start_secondary+0x2f4/0x410 [ 73.792637][ C1] secondary_startup_64+0xa4/0xb0 [ 73.799278][ C1] INITIAL USE at: [ 73.803152][ C1] lock_acquire+0x190/0x410 [ 73.809205][ C1] _raw_spin_lock_irq+0x60/0x80 [ 73.815594][ C1] io_submit_one+0xeb5/0x2ef0 [ 73.821807][ C1] __x64_sys_io_submit+0x1bd/0x570 [ 73.828453][ C1] do_syscall_64+0xfa/0x760 [ 73.834502][ C1] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 73.841942][ C1] } [ 73.844435][ C1] ... key at: [] __key.54358+0x0/0x40 [ 73.851872][ C1] ... acquired at: [ 73.855679][ C1] mark_lock+0x517/0x1220 [ 73.860162][ C1] __lock_acquire+0x1e8e/0x4a00 [ 73.865159][ C1] lock_acquire+0x190/0x410 [ 73.869813][ C1] _raw_spin_lock_irq+0x60/0x80 [ 73.874813][ C1] free_ioctx_users+0x2d/0x490 [ 73.879739][ C1] percpu_ref_switch_to_atomic_rcu+0x4c0/0x570 [ 73.886035][ C1] rcu_core+0x581/0x1560 [ 73.890421][ C1] rcu_core_si+0x9/0x10 [ 73.894733][ C1] __do_softirq+0x262/0x98c [ 73.899382][ C1] irq_exit+0x19b/0x1e0 [ 73.903686][ C1] smp_apic_timer_interrupt+0x1a3/0x610 [ 73.909378][ C1] apic_timer_interrupt+0xf/0x20 [ 73.914466][ C1] native_safe_halt+0xe/0x10 [ 73.919202][ C1] default_enter_idle+0x71/0xf0 [ 73.924201][ C1] cpuidle_enter_state+0xef/0xfb0 [ 73.929462][ C1] cpuidle_enter+0x4f/0xa0 [ 73.934032][ C1] do_idle+0x45f/0x6e0 [ 73.938252][ C1] cpu_startup_entry+0x1b/0x20 [ 73.943173][ C1] start_secondary+0x2f4/0x410 [ 73.948099][ C1] secondary_startup_64+0xa4/0xb0 [ 73.953280][ C1] [ 73.955598][ C1] [ 73.955598][ C1] stack backtrace: [ 73.961478][ C1] CPU: 1 PID: 0 Comm: swapper/1 Not tainted 5.3.0-rc6-next-20190830 #75 [ 73.969777][ C1] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 73.979808][ C1] Call Trace: [ 73.983068][ C1] [ 73.985912][ C1] dump_stack+0x172/0x1f0 [ 73.990224][ C1] print_irq_inversion_bug.part.0+0x2e4/0x2f1 [ 73.996270][ C1] check_usage_forwards.cold+0x20/0x29 [ 74.001712][ C1] ? check_usage_backwards+0x330/0x330 [ 74.007146][ C1] ? save_trace+0x3e/0x8c0 [ 74.011552][ C1] mark_lock+0x517/0x1220 [ 74.015863][ C1] ? check_usage_backwards+0x330/0x330 [ 74.021313][ C1] __lock_acquire+0x1e8e/0x4a00 [ 74.026143][ C1] ? __kasan_check_read+0x11/0x20 [ 74.031150][ C1] ? mark_lock+0xc2/0x1220 [ 74.035546][ C1] ? mark_held_locks+0xf0/0xf0 [ 74.040288][ C1] lock_acquire+0x190/0x410 [ 74.044784][ C1] ? free_ioctx_users+0x2d/0x490 [ 74.049698][ C1] _raw_spin_lock_irq+0x60/0x80 [ 74.054557][ C1] ? free_ioctx_users+0x2d/0x490 [ 74.059486][ C1] free_ioctx_users+0x2d/0x490 [ 74.064229][ C1] ? rcu_dynticks_curr_cpu_in_eqs+0x54/0xb0 [ 74.070102][ C1] percpu_ref_switch_to_atomic_rcu+0x4c0/0x570 [ 74.076235][ C1] ? percpu_ref_exit+0xd0/0xd0 [ 74.080974][ C1] rcu_core+0x581/0x1560 [ 74.085192][ C1] ? __rcu_read_unlock+0x6b0/0x6b0 [ 74.090290][ C1] ? rcu_read_lock_sched_held+0x9c/0xd0 [ 74.095825][ C1] ? rcu_read_lock_any_held.part.0+0x50/0x50 [ 74.104909][ C1] ? run_rebalance_domains+0x227/0x2d0 [ 74.110426][ C1] rcu_core_si+0x9/0x10 [ 74.114573][ C1] __do_softirq+0x262/0x98c [ 74.119049][ C1] ? sched_clock_cpu+0x1b/0x1b0 [ 74.123872][ C1] irq_exit+0x19b/0x1e0 [ 74.127999][ C1] smp_apic_timer_interrupt+0x1a3/0x610 [ 74.133515][ C1] apic_timer_interrupt+0xf/0x20 [ 74.138421][ C1] [ 74.141697][ C1] RIP: 0010:native_safe_halt+0xe/0x10 [ 74.147073][ 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 [ 74.167178][ C1] RSP: 0018:ffff8880a98dfcd0 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff13 [ 74.175566][ C1] RAX: 1ffffffff11e5db7 RBX: 0000000000000000 RCX: 0000000000000000 [ 74.183622][ C1] RDX: dffffc0000000000 RSI: 0000000000000006 RDI: ffff8880a98d0bdc [ 74.191606][ C1] RBP: ffff8880a98dfd00 R08: ffff8880a98d0340 R09: 0000000000000000 [ 74.199558][ C1] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000001 [ 74.207523][ C1] R13: 0000000000000000 R14: 0000000000000060 R15: 0000000000000001 [ 74.215505][ C1] ? default_idle+0x4e/0x360 [ 74.220082][ C1] default_enter_idle+0x71/0xf0 [ 74.224920][ C1] cpuidle_enter_state+0xef/0xfb0 [ 74.229924][ C1] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 74.236145][ C1] cpuidle_enter+0x4f/0xa0 [ 74.240541][ C1] do_idle+0x45f/0x6e0 [ 74.244588][ C1] ? arch_cpu_idle_exit+0x80/0x80 [ 74.249602][ C1] ? _raw_spin_unlock_irqrestore+0x40/0xe0 [ 74.255383][ C1] ? complete+0x61/0x80 [ 74.259522][ C1] cpu_startup_entry+0x1b/0x20 [ 74.264262][ C1] start_secondary+0x2f4/0x410 [ 74.268998][ C1] ? set_cpu_sibling_map+0x2180/0x2180 [ 74.274434][ C1] secondary_startup_64+0xa4/0xb0