[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [ 54.809573][ T26] audit: type=1800 audit(1567350855.889:25): pid=8413 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="cron" dev="sda1" ino=2414 res=0 [ 54.854568][ T26] audit: type=1800 audit(1567350855.889:26): pid=8413 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="mcstrans" dev="sda1" ino=2457 res=0 [ 54.880144][ T26] audit: type=1800 audit(1567350855.889:27): pid=8413 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 '10.128.10.62' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 63.217182][ C0] [ 63.219542][ C0] ======================================================== [ 63.226718][ C0] WARNING: possible irq lock inversion dependency detected [ 63.233883][ C0] 5.3.0-rc6-next-20190830 #75 Not tainted [ 63.239570][ C0] -------------------------------------------------------- [ 63.246736][ C0] swapper/0/0 just changed the state of lock: [ 63.252771][ C0] ffff88809592fb58 (&(&ctx->ctx_lock)->rlock){..-.}, at: free_ioctx_users+0x2d/0x490 [ 63.262211][ C0] but this lock took another, SOFTIRQ-unsafe lock in the past: [ 63.269717][ C0] (&fiq->waitq){+.+.} [ 63.269723][ C0] [ 63.269723][ C0] [ 63.269723][ C0] and interrupts could create inverse lock ordering between them. [ 63.269723][ C0] [ 63.288056][ C0] [ 63.288056][ C0] other info that might help us debug this: [ 63.296104][ C0] Possible interrupt unsafe locking scenario: [ 63.296104][ C0] [ 63.304394][ C0] CPU0 CPU1 [ 63.309731][ C0] ---- ---- [ 63.315066][ C0] lock(&fiq->waitq); [ 63.319100][ C0] local_irq_disable(); [ 63.325822][ C0] lock(&(&ctx->ctx_lock)->rlock); [ 63.333507][ C0] lock(&fiq->waitq); [ 63.340076][ C0] [ 63.343503][ C0] lock(&(&ctx->ctx_lock)->rlock); [ 63.348949][ C0] [ 63.348949][ C0] *** DEADLOCK *** [ 63.348949][ C0] [ 63.357070][ C0] 2 locks held by swapper/0/0: [ 63.361800][ C0] #0: ffffffff88fa7e40 (rcu_callback){....}, at: rcu_core+0x60e/0x1560 [ 63.370124][ C0] #1: ffffffff88fa7e80 (rcu_read_lock_sched){....}, at: percpu_ref_switch_to_atomic_rcu+0x20e/0x570 [ 63.380956][ C0] [ 63.380956][ C0] the shortest dependencies between 2nd lock and 1st lock: [ 63.390298][ C0] -> (&fiq->waitq){+.+.} { [ 63.394805][ C0] HARDIRQ-ON-W at: [ 63.398873][ C0] lock_acquire+0x190/0x410 [ 63.405175][ C0] _raw_spin_lock+0x2f/0x40 [ 63.411472][ C0] flush_bg_queue+0x1f1/0x3b0 [ 63.417944][ C0] fuse_request_queue_background+0x2f8/0x5b0 [ 63.425716][ C0] fuse_request_send_background+0x58/0x110 [ 63.433334][ C0] cuse_channel_open+0x5c3/0x839 [ 63.440067][ C0] misc_open+0x395/0x4c0 [ 63.446108][ C0] chrdev_open+0x245/0x6b0 [ 63.452323][ C0] do_dentry_open+0x4df/0x1250 [ 63.458879][ C0] vfs_open+0xa0/0xd0 [ 63.464657][ C0] path_openat+0x10e9/0x46d0 [ 63.471041][ C0] do_filp_open+0x1a1/0x280 [ 63.477339][ C0] do_sys_open+0x3fe/0x5d0 [ 63.483547][ C0] __x64_sys_openat+0x9d/0x100 [ 63.490104][ C0] do_syscall_64+0xfa/0x760 [ 63.496404][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 63.504086][ C0] SOFTIRQ-ON-W at: [ 63.508146][ C0] lock_acquire+0x190/0x410 [ 63.514447][ C0] _raw_spin_lock+0x2f/0x40 [ 63.520752][ C0] flush_bg_queue+0x1f1/0x3b0 [ 63.527224][ C0] fuse_request_queue_background+0x2f8/0x5b0 [ 63.534997][ C0] fuse_request_send_background+0x58/0x110 [ 63.542594][ C0] cuse_channel_open+0x5c3/0x839 [ 63.549324][ C0] misc_open+0x395/0x4c0 [ 63.555369][ C0] chrdev_open+0x245/0x6b0 [ 63.561581][ C0] do_dentry_open+0x4df/0x1250 [ 63.568142][ C0] vfs_open+0xa0/0xd0 [ 63.573918][ C0] path_openat+0x10e9/0x46d0 [ 63.580302][ C0] do_filp_open+0x1a1/0x280 [ 63.586616][ C0] do_sys_open+0x3fe/0x5d0 [ 63.592832][ C0] __x64_sys_openat+0x9d/0x100 [ 63.599389][ C0] do_syscall_64+0xfa/0x760 [ 63.605688][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 63.613370][ C0] INITIAL USE at: [ 63.617324][ C0] lock_acquire+0x190/0x410 [ 63.623532][ C0] _raw_spin_lock+0x2f/0x40 [ 63.629741][ C0] flush_bg_queue+0x1f1/0x3b0 [ 63.636130][ C0] fuse_request_queue_background+0x2f8/0x5b0 [ 63.643817][ C0] fuse_request_send_background+0x58/0x110 [ 63.651329][ C0] cuse_channel_open+0x5c3/0x839 [ 63.657977][ C0] misc_open+0x395/0x4c0 [ 63.663928][ C0] chrdev_open+0x245/0x6b0 [ 63.670055][ C0] do_dentry_open+0x4df/0x1250 [ 63.676528][ C0] vfs_open+0xa0/0xd0 [ 63.682234][ C0] path_openat+0x10e9/0x46d0 [ 63.688532][ C0] do_filp_open+0x1a1/0x280 [ 63.694746][ C0] do_sys_open+0x3fe/0x5d0 [ 63.700868][ C0] __x64_sys_openat+0x9d/0x100 [ 63.707338][ C0] do_syscall_64+0xfa/0x760 [ 63.713566][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 63.721159][ C0] } [ 63.723726][ C0] ... key at: [] __key.44810+0x0/0x40 [ 63.731233][ C0] ... acquired at: [ 63.735113][ C0] _raw_spin_lock+0x2f/0x40 [ 63.739767][ C0] io_submit_one+0xefa/0x2ef0 [ 63.744587][ C0] __x64_sys_io_submit+0x1bd/0x570 [ 63.749856][ C0] do_syscall_64+0xfa/0x760 [ 63.754505][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 63.760533][ C0] [ 63.762831][ C0] -> (&(&ctx->ctx_lock)->rlock){..-.} { [ 63.768346][ C0] IN-SOFTIRQ-W at: [ 63.772301][ C0] lock_acquire+0x190/0x410 [ 63.778511][ C0] _raw_spin_lock_irq+0x60/0x80 [ 63.784981][ C0] free_ioctx_users+0x2d/0x490 [ 63.791366][ C0] percpu_ref_switch_to_atomic_rcu+0x4c0/0x570 [ 63.799139][ C0] rcu_core+0x581/0x1560 [ 63.805000][ C0] rcu_core_si+0x9/0x10 [ 63.810777][ C0] __do_softirq+0x262/0x98c [ 63.816899][ C0] irq_exit+0x19b/0x1e0 [ 63.822673][ C0] smp_apic_timer_interrupt+0x1a3/0x610 [ 63.829839][ C0] apic_timer_interrupt+0xf/0x20 [ 63.836396][ C0] native_safe_halt+0xe/0x10 [ 63.842607][ C0] default_enter_idle+0x71/0xf0 [ 63.849078][ C0] cpuidle_enter_state+0xef/0xfb0 [ 63.855722][ C0] cpuidle_enter+0x4f/0xa0 [ 63.861779][ C0] do_idle+0x45f/0x6e0 [ 63.867492][ C0] cpu_startup_entry+0x1b/0x20 [ 63.873877][ C0] rest_init+0x245/0x37b [ 63.879744][ C0] arch_call_rest_init+0xe/0x1b [ 63.886231][ C0] start_kernel+0x904/0x943 [ 63.892370][ C0] x86_64_start_reservations+0x29/0x2b [ 63.899448][ C0] x86_64_start_kernel+0x77/0x7b [ 63.906007][ C0] secondary_startup_64+0xa4/0xb0 [ 63.912648][ C0] INITIAL USE at: [ 63.916520][ C0] lock_acquire+0x190/0x410 [ 63.922557][ C0] _raw_spin_lock_irq+0x60/0x80 [ 63.928941][ C0] io_submit_one+0xeb5/0x2ef0 [ 63.935150][ C0] __x64_sys_io_submit+0x1bd/0x570 [ 63.941794][ C0] do_syscall_64+0xfa/0x760 [ 63.947832][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 63.955266][ C0] } [ 63.957762][ C0] ... key at: [] __key.54358+0x0/0x40 [ 63.965182][ C0] ... acquired at: [ 63.968962][ C0] mark_lock+0x517/0x1220 [ 63.973450][ C0] __lock_acquire+0x1e8e/0x4a00 [ 63.978462][ C0] lock_acquire+0x190/0x410 [ 63.983111][ C0] _raw_spin_lock_irq+0x60/0x80 [ 63.988104][ C0] free_ioctx_users+0x2d/0x490 [ 63.993013][ C0] percpu_ref_switch_to_atomic_rcu+0x4c0/0x570 [ 63.999312][ C0] rcu_core+0x581/0x1560 [ 64.003694][ C0] rcu_core_si+0x9/0x10 [ 64.008008][ C0] __do_softirq+0x262/0x98c [ 64.012654][ C0] irq_exit+0x19b/0x1e0 [ 64.016959][ C0] smp_apic_timer_interrupt+0x1a3/0x610 [ 64.022647][ C0] apic_timer_interrupt+0xf/0x20 [ 64.027736][ C0] native_safe_halt+0xe/0x10 [ 64.032480][ C0] default_enter_idle+0x71/0xf0 [ 64.037474][ C0] cpuidle_enter_state+0xef/0xfb0 [ 64.042640][ C0] cpuidle_enter+0x4f/0xa0 [ 64.047200][ C0] do_idle+0x45f/0x6e0 [ 64.051414][ C0] cpu_startup_entry+0x1b/0x20 [ 64.056324][ C0] rest_init+0x245/0x37b [ 64.060715][ C0] arch_call_rest_init+0xe/0x1b [ 64.065714][ C0] start_kernel+0x904/0x943 [ 64.070364][ C0] x86_64_start_reservations+0x29/0x2b [ 64.075965][ C0] x86_64_start_kernel+0x77/0x7b [ 64.081136][ C0] secondary_startup_64+0xa4/0xb0 [ 64.086307][ C0] [ 64.088606][ C0] [ 64.088606][ C0] stack backtrace: [ 64.094476][ C0] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.3.0-rc6-next-20190830 #75 [ 64.102769][ C0] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 64.112809][ C0] Call Trace: [ 64.116064][ C0] [ 64.118891][ C0] dump_stack+0x172/0x1f0 [ 64.123192][ C0] print_irq_inversion_bug.part.0+0x2e4/0x2f1 [ 64.129230][ C0] check_usage_forwards.cold+0x20/0x29 [ 64.134657][ C0] ? check_usage_backwards+0x330/0x330 [ 64.140088][ C0] ? save_trace+0x3e/0x8c0 [ 64.144477][ C0] mark_lock+0x517/0x1220 [ 64.148777][ C0] ? check_usage_backwards+0x330/0x330 [ 64.154216][ C0] __lock_acquire+0x1e8e/0x4a00 [ 64.159039][ C0] ? __kasan_check_read+0x11/0x20 [ 64.164034][ C0] ? mark_lock+0xc2/0x1220 [ 64.168422][ C0] ? mark_held_locks+0xf0/0xf0 [ 64.173158][ C0] lock_acquire+0x190/0x410 [ 64.177633][ C0] ? free_ioctx_users+0x2d/0x490 [ 64.182541][ C0] _raw_spin_lock_irq+0x60/0x80 [ 64.187364][ C0] ? free_ioctx_users+0x2d/0x490 [ 64.192273][ C0] free_ioctx_users+0x2d/0x490 [ 64.197014][ C0] ? rcu_dynticks_curr_cpu_in_eqs+0x54/0xb0 [ 64.202880][ C0] percpu_ref_switch_to_atomic_rcu+0x4c0/0x570 [ 64.209005][ C0] ? percpu_ref_exit+0xd0/0xd0 [ 64.213740][ C0] rcu_core+0x581/0x1560 [ 64.217971][ C0] ? __rcu_read_unlock+0x6b0/0x6b0 [ 64.223052][ C0] ? rcu_read_lock_sched_held+0x9c/0xd0 [ 64.228577][ C0] ? rcu_read_lock_any_held.part.0+0x50/0x50 [ 64.234526][ C0] ? run_rebalance_domains+0x227/0x2d0 [ 64.239965][ C0] rcu_core_si+0x9/0x10 [ 64.244091][ C0] __do_softirq+0x262/0x98c [ 64.248565][ C0] ? sched_clock_cpu+0x1b/0x1b0 [ 64.253390][ C0] irq_exit+0x19b/0x1e0 [ 64.257518][ C0] smp_apic_timer_interrupt+0x1a3/0x610 [ 64.263051][ C0] apic_timer_interrupt+0xf/0x20 [ 64.267964][ C0] [ 64.270891][ C0] RIP: 0010:native_safe_halt+0xe/0x10 [ 64.276239][ 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 [ 64.295815][ C0] RSP: 0018:ffffffff88e07c50 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff13 [ 64.304197][ C0] RAX: 1ffffffff11e5db7 RBX: 0000000000000000 RCX: 0000000000000000 [ 64.312144][ C0] RDX: dffffc0000000000 RSI: 0000000000000006 RDI: ffffffff88e7aa1c [ 64.320089][ C0] RBP: ffffffff88e07c80 R08: ffffffff88e7a180 R09: 0000000000000000 [ 64.328033][ C0] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000001 [ 64.335977][ C0] R13: 0000000000000000 R14: 0000000000000060 R15: 0000000000000001 [ 64.343933][ C0] ? default_idle+0x4e/0x360 [ 64.348537][ C0] default_enter_idle+0x71/0xf0 [ 64.353362][ C0] cpuidle_enter_state+0xef/0xfb0 [ 64.358362][ C0] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 64.364575][ C0] cpuidle_enter+0x4f/0xa0 [ 64.368967][ C0] do_idle+0x45f/0x6e0 [ 64.373007][ C0] ? arch_cpu_idle_exit+0x80/0x80 [ 64.379146][ C0] ? trace_hardirqs_on+0x30/0x240 [ 64.384146][ C0] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 64.390373][ C0] ? debug_smp_processor_id+0x3c/0x214 [ 64.395811][ C0] cpu_startup_entry+0x1b/0x20 [ 64.400566][ C0] rest_init+0x245/0x37b [ 64.404782][ C0] arch_call_rest_init+0xe/0x1b [ 64.409605][ C0] start_kernel+0x904/0x943 [ 64.414085][ C0] ? mem_encrypt_init+0xb/0xb [ 64.418738][ C0] ? __sanitizer_cov_tr