[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [ 55.758881][ T26] audit: type=1800 audit(1567481467.949:25): pid=8665 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="cron" dev="sda1" ino=2414 res=0 [ 55.802489][ T26] audit: type=1800 audit(1567481467.959:26): pid=8665 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="mcstrans" dev="sda1" ino=2457 res=0 [ 55.842280][ T26] audit: type=1800 audit(1567481467.959:27): pid=8665 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 '10.128.15.211' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 67.542394][ C1] [ 67.544766][ C1] ======================================================== [ 67.551946][ C1] WARNING: possible irq lock inversion dependency detected [ 67.559115][ C1] 5.3.0-rc6-next-20190830 #75 Not tainted [ 67.564804][ C1] -------------------------------------------------------- [ 67.571968][ C1] swapper/1/0 just changed the state of lock: [ 67.578015][ C1] ffff8880911ebb58 (&(&ctx->ctx_lock)->rlock){..-.}, at: free_ioctx_users+0x2d/0x490 [ 67.587454][ C1] but this lock took another, SOFTIRQ-unsafe lock in the past: [ 67.594964][ C1] (&fiq->waitq){+.+.} [ 67.594971][ C1] [ 67.594971][ C1] [ 67.594971][ C1] and interrupts could create inverse lock ordering between them. [ 67.594971][ C1] [ 67.613314][ C1] [ 67.613314][ C1] other info that might help us debug this: [ 67.621347][ C1] Possible interrupt unsafe locking scenario: [ 67.621347][ C1] [ 67.629652][ C1] CPU0 CPU1 [ 67.635005][ C1] ---- ---- [ 67.640345][ C1] lock(&fiq->waitq); [ 67.644384][ C1] local_irq_disable(); [ 67.651123][ C1] lock(&(&ctx->ctx_lock)->rlock); [ 67.658899][ C1] lock(&fiq->waitq); [ 67.665461][ C1] [ 67.668891][ C1] lock(&(&ctx->ctx_lock)->rlock); [ 67.674234][ C1] [ 67.674234][ C1] *** DEADLOCK *** [ 67.674234][ C1] [ 67.682358][ C1] 2 locks held by swapper/1/0: [ 67.687183][ C1] #0: ffffffff88fa7e40 (rcu_callback){....}, at: rcu_core+0x60e/0x1560 [ 67.695532][ C1] #1: ffffffff88fa7e80 (rcu_read_lock_sched){....}, at: percpu_ref_switch_to_atomic_rcu+0x20e/0x570 [ 67.706383][ C1] [ 67.706383][ C1] the shortest dependencies between 2nd lock and 1st lock: [ 67.715731][ C1] -> (&fiq->waitq){+.+.} { [ 67.720209][ C1] HARDIRQ-ON-W at: [ 67.724262][ C1] lock_acquire+0x190/0x410 [ 67.730577][ C1] _raw_spin_lock+0x2f/0x40 [ 67.736877][ C1] flush_bg_queue+0x1f1/0x3b0 [ 67.743368][ C1] fuse_request_queue_background+0x2f8/0x5b0 [ 67.751165][ C1] fuse_request_send_background+0x58/0x110 [ 67.758780][ C1] cuse_channel_open+0x5c3/0x839 [ 67.765531][ C1] misc_open+0x395/0x4c0 [ 67.771575][ C1] chrdev_open+0x245/0x6b0 [ 67.777790][ C1] do_dentry_open+0x4df/0x1250 [ 67.784367][ C1] vfs_open+0xa0/0xd0 [ 67.790159][ C1] path_openat+0x10e9/0x46d0 [ 67.796556][ C1] do_filp_open+0x1a1/0x280 [ 67.802872][ C1] do_sys_open+0x3fe/0x5d0 [ 67.809082][ C1] __x64_sys_openat+0x9d/0x100 [ 67.815645][ C1] do_syscall_64+0xfa/0x760 [ 67.821960][ C1] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 67.829776][ C1] SOFTIRQ-ON-W at: [ 67.833875][ C1] lock_acquire+0x190/0x410 [ 67.840182][ C1] _raw_spin_lock+0x2f/0x40 [ 67.846487][ C1] flush_bg_queue+0x1f1/0x3b0 [ 67.852965][ C1] fuse_request_queue_background+0x2f8/0x5b0 [ 67.860740][ C1] fuse_request_send_background+0x58/0x110 [ 67.868341][ C1] cuse_channel_open+0x5c3/0x839 [ 67.875078][ C1] misc_open+0x395/0x4c0 [ 67.881119][ C1] chrdev_open+0x245/0x6b0 [ 67.887348][ C1] do_dentry_open+0x4df/0x1250 [ 67.893915][ C1] vfs_open+0xa0/0xd0 [ 67.899694][ C1] path_openat+0x10e9/0x46d0 [ 67.906078][ C1] do_filp_open+0x1a1/0x280 [ 67.912507][ C1] do_sys_open+0x3fe/0x5d0 [ 67.918728][ C1] __x64_sys_openat+0x9d/0x100 [ 67.925302][ C1] do_syscall_64+0xfa/0x760 [ 67.931612][ C1] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 67.939297][ C1] INITIAL USE at: [ 67.943258][ C1] lock_acquire+0x190/0x410 [ 67.949481][ C1] _raw_spin_lock+0x2f/0x40 [ 67.955704][ C1] flush_bg_queue+0x1f1/0x3b0 [ 67.962127][ C1] fuse_request_queue_background+0x2f8/0x5b0 [ 67.969847][ C1] fuse_request_send_background+0x58/0x110 [ 67.977374][ C1] cuse_channel_open+0x5c3/0x839 [ 67.984025][ C1] misc_open+0x395/0x4c0 [ 67.989980][ C1] chrdev_open+0x245/0x6b0 [ 67.996137][ C1] do_dentry_open+0x4df/0x1250 [ 68.002626][ C1] vfs_open+0xa0/0xd0 [ 68.008321][ C1] path_openat+0x10e9/0x46d0 [ 68.014621][ C1] do_filp_open+0x1a1/0x280 [ 68.020841][ C1] do_sys_open+0x3fe/0x5d0 [ 68.026963][ C1] __x64_sys_openat+0x9d/0x100 [ 68.033439][ C1] do_syscall_64+0xfa/0x760 [ 68.039752][ C1] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 68.047366][ C1] } [ 68.049937][ C1] ... key at: [] __key.44810+0x0/0x40 [ 68.057463][ C1] ... acquired at: [ 68.061332][ C1] _raw_spin_lock+0x2f/0x40 [ 68.065985][ C1] io_submit_one+0xefa/0x2ef0 [ 68.070807][ C1] __x64_sys_io_submit+0x1bd/0x570 [ 68.076070][ C1] do_syscall_64+0xfa/0x760 [ 68.080719][ C1] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 68.086751][ C1] [ 68.089049][ C1] -> (&(&ctx->ctx_lock)->rlock){..-.} { [ 68.094567][ C1] IN-SOFTIRQ-W at: [ 68.098525][ C1] lock_acquire+0x190/0x410 [ 68.104651][ C1] _raw_spin_lock_irq+0x60/0x80 [ 68.111123][ C1] free_ioctx_users+0x2d/0x490 [ 68.117520][ C1] percpu_ref_switch_to_atomic_rcu+0x4c0/0x570 [ 68.125490][ C1] rcu_core+0x581/0x1560 [ 68.131381][ C1] rcu_core_si+0x9/0x10 [ 68.137179][ C1] __do_softirq+0x262/0x98c [ 68.143312][ C1] irq_exit+0x19b/0x1e0 [ 68.149092][ C1] smp_apic_timer_interrupt+0x1a3/0x610 [ 68.156272][ C1] apic_timer_interrupt+0xf/0x20 [ 68.162869][ C1] native_safe_halt+0xe/0x10 [ 68.169083][ C1] default_enter_idle+0x71/0xf0 [ 68.175575][ C1] cpuidle_enter_state+0xef/0xfb0 [ 68.182224][ C1] cpuidle_enter+0x4f/0xa0 [ 68.188277][ C1] do_idle+0x45f/0x6e0 [ 68.193972][ C1] cpu_startup_entry+0x1b/0x20 [ 68.200361][ C1] start_secondary+0x2f4/0x410 [ 68.206749][ C1] secondary_startup_64+0xa4/0xb0 [ 68.213393][ C1] INITIAL USE at: [ 68.217278][ C1] lock_acquire+0x190/0x410 [ 68.223318][ C1] _raw_spin_lock_irq+0x60/0x80 [ 68.229719][ C1] io_submit_one+0xeb5/0x2ef0 [ 68.235948][ C1] __x64_sys_io_submit+0x1bd/0x570 [ 68.242654][ C1] do_syscall_64+0xfa/0x760 [ 68.248710][ C1] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 68.256251][ C1] } [ 68.258757][ C1] ... key at: [] __key.54358+0x0/0x40 [ 68.266185][ C1] ... acquired at: [ 68.269972][ C1] mark_lock+0x517/0x1220 [ 68.274473][ C1] __lock_acquire+0x1e8e/0x4a00 [ 68.279468][ C1] lock_acquire+0x190/0x410 [ 68.284122][ C1] _raw_spin_lock_irq+0x60/0x80 [ 68.289119][ C1] free_ioctx_users+0x2d/0x490 [ 68.294032][ C1] percpu_ref_switch_to_atomic_rcu+0x4c0/0x570 [ 68.300330][ C1] rcu_core+0x581/0x1560 [ 68.304728][ C1] rcu_core_si+0x9/0x10 [ 68.309123][ C1] __do_softirq+0x262/0x98c [ 68.313777][ C1] irq_exit+0x19b/0x1e0 [ 68.318082][ C1] smp_apic_timer_interrupt+0x1a3/0x610 [ 68.323781][ C1] apic_timer_interrupt+0xf/0x20 [ 68.328873][ C1] native_safe_halt+0xe/0x10 [ 68.333612][ C1] default_enter_idle+0x71/0xf0 [ 68.338610][ C1] cpuidle_enter_state+0xef/0xfb0 [ 68.344242][ C1] cpuidle_enter+0x4f/0xa0 [ 68.348807][ C1] do_idle+0x45f/0x6e0 [ 68.353107][ C1] cpu_startup_entry+0x1b/0x20 [ 68.358018][ C1] start_secondary+0x2f4/0x410 [ 68.362928][ C1] secondary_startup_64+0xa4/0xb0 [ 68.368093][ C1] [ 68.370395][ C1] [ 68.370395][ C1] stack backtrace: [ 68.376348][ C1] CPU: 1 PID: 0 Comm: swapper/1 Not tainted 5.3.0-rc6-next-20190830 #75 [ 68.384651][ C1] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 68.394689][ C1] Call Trace: [ 68.397948][ C1] [ 68.400783][ C1] dump_stack+0x172/0x1f0 [ 68.405094][ C1] print_irq_inversion_bug.part.0+0x2e4/0x2f1 [ 68.411144][ C1] check_usage_forwards.cold+0x20/0x29 [ 68.416578][ C1] ? check_usage_backwards+0x330/0x330 [ 68.422012][ C1] ? save_trace+0x3e/0x8c0 [ 68.426419][ C1] mark_lock+0x517/0x1220 [ 68.430762][ C1] ? check_usage_backwards+0x330/0x330 [ 68.436211][ C1] __lock_acquire+0x1e8e/0x4a00 [ 68.441051][ C1] ? __kasan_check_read+0x11/0x20 [ 68.446062][ C1] ? mark_lock+0xc2/0x1220 [ 68.450481][ C1] ? mark_held_locks+0xf0/0xf0 [ 68.455235][ C1] lock_acquire+0x190/0x410 [ 68.459726][ C1] ? free_ioctx_users+0x2d/0x490 [ 68.464654][ C1] _raw_spin_lock_irq+0x60/0x80 [ 68.469564][ C1] ? free_ioctx_users+0x2d/0x490 [ 68.474479][ C1] free_ioctx_users+0x2d/0x490 [ 68.479220][ C1] ? rcu_dynticks_curr_cpu_in_eqs+0x54/0xb0 [ 68.485274][ C1] percpu_ref_switch_to_atomic_rcu+0x4c0/0x570 [ 68.491401][ C1] ? percpu_ref_exit+0xd0/0xd0 [ 68.496152][ C1] rcu_core+0x581/0x1560 [ 68.500457][ C1] ? __rcu_read_unlock+0x6b0/0x6b0 [ 68.505545][ C1] ? rcu_read_lock_sched_held+0x9c/0xd0 [ 68.511076][ C1] ? rcu_read_lock_any_held.part.0+0x50/0x50 [ 68.517049][ C1] ? run_rebalance_domains+0x227/0x2d0 [ 68.522482][ C1] rcu_core_si+0x9/0x10 [ 68.526622][ C1] __do_softirq+0x262/0x98c [ 68.531101][ C1] ? sched_clock_cpu+0x1b/0x1b0 [ 68.535939][ C1] irq_exit+0x19b/0x1e0 [ 68.540072][ C1] smp_apic_timer_interrupt+0x1a3/0x610 [ 68.545603][ C1] apic_timer_interrupt+0xf/0x20 [ 68.550524][ C1] [ 68.553453][ C1] RIP: 0010:native_safe_halt+0xe/0x10 [ 68.558803][ 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 [ 68.578400][ C1] RSP: 0018:ffff8880a98dfcd0 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff13 [ 68.586788][ C1] RAX: 1ffffffff11e5db7 RBX: 0000000000000000 RCX: 0000000000000000 [ 68.594738][ C1] RDX: dffffc0000000000 RSI: 0000000000000006 RDI: ffff8880a98d0bdc [ 68.602689][ C1] RBP: ffff8880a98dfd00 R08: ffff8880a98d0340 R09: 0000000000000000 [ 68.610635][ C1] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000001 [ 68.618597][ C1] R13: 0000000000000000 R14: 0000000000000060 R15: 0000000000000001 [ 68.626560][ C1] ? default_idle+0x4e/0x360 [ 68.631126][ C1] default_enter_idle+0x71/0xf0 [ 68.635953][ C1] cpuidle_enter_state+0xef/0xfb0 [ 68.640956][ C1] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [