[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [ 54.554428][ T26] audit: type=1800 audit(1568200401.285:25): pid=8544 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="cron" dev="sda1" ino=2414 res=0 [ 54.591986][ T26] audit: type=1800 audit(1568200401.285:26): pid=8544 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="mcstrans" dev="sda1" ino=2457 res=0 [ 54.623745][ T26] audit: type=1800 audit(1568200401.295:27): pid=8544 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 '10.128.1.19' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 66.021875][ C1] [ 66.024340][ C1] ======================================================== [ 66.031519][ C1] WARNING: possible irq lock inversion dependency detected [ 66.038689][ C1] 5.3.0-rc6-next-20190830 #75 Not tainted [ 66.044419][ C1] -------------------------------------------------------- [ 66.051583][ C1] swapper/1/0 just changed the state of lock: [ 66.057619][ C1] ffff888098755b58 (&(&ctx->ctx_lock)->rlock){..-.}, at: free_ioctx_users+0x2d/0x490 [ 66.067073][ C1] but this lock took another, SOFTIRQ-unsafe lock in the past: [ 66.074677][ C1] (&fiq->waitq){+.+.} [ 66.074683][ C1] [ 66.074683][ C1] [ 66.074683][ C1] and interrupts could create inverse lock ordering between them. [ 66.074683][ C1] [ 66.093020][ C1] [ 66.093020][ C1] other info that might help us debug this: [ 66.101054][ C1] Possible interrupt unsafe locking scenario: [ 66.101054][ C1] [ 66.109344][ C1] CPU0 CPU1 [ 66.114683][ C1] ---- ---- [ 66.120026][ C1] lock(&fiq->waitq); [ 66.124075][ C1] local_irq_disable(); [ 66.130812][ C1] lock(&(&ctx->ctx_lock)->rlock); [ 66.138510][ C1] lock(&fiq->waitq); [ 66.145076][ C1] [ 66.148510][ C1] lock(&(&ctx->ctx_lock)->rlock); [ 66.153854][ C1] [ 66.153854][ C1] *** DEADLOCK *** [ 66.153854][ C1] [ 66.161991][ C1] 2 locks held by swapper/1/0: [ 66.166733][ C1] #0: ffffffff88fa7e40 (rcu_callback){....}, at: rcu_core+0x60e/0x1560 [ 66.175042][ C1] #1: ffffffff88fa7e80 (rcu_read_lock_sched){....}, at: percpu_ref_switch_to_atomic_rcu+0x20e/0x570 [ 66.185879][ C1] [ 66.185879][ C1] the shortest dependencies between 2nd lock and 1st lock: [ 66.195222][ C1] -> (&fiq->waitq){+.+.} { [ 66.199700][ C1] HARDIRQ-ON-W at: [ 66.203750][ C1] lock_acquire+0x190/0x410 [ 66.210069][ C1] _raw_spin_lock+0x2f/0x40 [ 66.216373][ C1] flush_bg_queue+0x1f1/0x3b0 [ 66.222848][ C1] fuse_request_queue_background+0x2f8/0x5b0 [ 66.231259][ C1] fuse_request_send_background+0x58/0x110 [ 66.238889][ C1] cuse_channel_open+0x5c3/0x839 [ 66.245625][ C1] misc_open+0x395/0x4c0 [ 66.251681][ C1] chrdev_open+0x245/0x6b0 [ 66.257898][ C1] do_dentry_open+0x4df/0x1250 [ 66.264460][ C1] vfs_open+0xa0/0xd0 [ 66.270251][ C1] path_openat+0x10e9/0x46d0 [ 66.276640][ C1] do_filp_open+0x1a1/0x280 [ 66.282940][ C1] do_sys_open+0x3fe/0x5d0 [ 66.289153][ C1] __x64_sys_openat+0x9d/0x100 [ 66.295724][ C1] do_syscall_64+0xfa/0x760 [ 66.302038][ C1] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 66.309725][ C1] SOFTIRQ-ON-W at: [ 66.313775][ C1] lock_acquire+0x190/0x410 [ 66.320347][ C1] _raw_spin_lock+0x2f/0x40 [ 66.326667][ C1] flush_bg_queue+0x1f1/0x3b0 [ 66.333143][ C1] fuse_request_queue_background+0x2f8/0x5b0 [ 66.340920][ C1] fuse_request_send_background+0x58/0x110 [ 66.348524][ C1] cuse_channel_open+0x5c3/0x839 [ 66.355272][ C1] misc_open+0x395/0x4c0 [ 66.361325][ C1] chrdev_open+0x245/0x6b0 [ 66.367542][ C1] do_dentry_open+0x4df/0x1250 [ 66.374103][ C1] vfs_open+0xa0/0xd0 [ 66.380928][ C1] path_openat+0x10e9/0x46d0 [ 66.387329][ C1] do_filp_open+0x1a1/0x280 [ 66.393634][ C1] do_sys_open+0x3fe/0x5d0 [ 66.399859][ C1] __x64_sys_openat+0x9d/0x100 [ 66.406507][ C1] do_syscall_64+0xfa/0x760 [ 66.412897][ C1] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 66.420596][ C1] INITIAL USE at: [ 66.424575][ C1] lock_acquire+0x190/0x410 [ 66.430797][ C1] _raw_spin_lock+0x2f/0x40 [ 66.437031][ C1] flush_bg_queue+0x1f1/0x3b0 [ 66.443607][ C1] fuse_request_queue_background+0x2f8/0x5b0 [ 66.451320][ C1] fuse_request_send_background+0x58/0x110 [ 66.458845][ C1] cuse_channel_open+0x5c3/0x839 [ 66.465671][ C1] misc_open+0x395/0x4c0 [ 66.471736][ C1] chrdev_open+0x245/0x6b0 [ 66.477876][ C1] do_dentry_open+0x4df/0x1250 [ 66.484358][ C1] vfs_open+0xa0/0xd0 [ 66.490057][ C1] path_openat+0x10e9/0x46d0 [ 66.496361][ C1] do_filp_open+0x1a1/0x280 [ 66.502590][ C1] do_sys_open+0x3fe/0x5d0 [ 66.508717][ C1] __x64_sys_openat+0x9d/0x100 [ 66.515194][ C1] do_syscall_64+0xfa/0x760 [ 66.521690][ C1] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 66.529305][ C1] } [ 66.531905][ C1] ... key at: [] __key.44810+0x0/0x40 [ 66.539417][ C1] ... acquired at: [ 66.543302][ C1] _raw_spin_lock+0x2f/0x40 [ 66.547970][ C1] io_submit_one+0xefa/0x2ef0 [ 66.552819][ C1] __x64_sys_io_submit+0x1bd/0x570 [ 66.558131][ C1] do_syscall_64+0xfa/0x760 [ 66.562788][ C1] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 66.568823][ C1] [ 66.571135][ C1] -> (&(&ctx->ctx_lock)->rlock){..-.} { [ 66.576660][ C1] IN-SOFTIRQ-W at: [ 66.580624][ C1] lock_acquire+0x190/0x410 [ 66.586753][ C1] _raw_spin_lock_irq+0x60/0x80 [ 66.593229][ C1] free_ioctx_users+0x2d/0x490 [ 66.599617][ C1] percpu_ref_switch_to_atomic_rcu+0x4c0/0x570 [ 66.607413][ C1] rcu_core+0x581/0x1560 [ 66.613279][ C1] rcu_core_si+0x9/0x10 [ 66.619056][ C1] __do_softirq+0x262/0x98c [ 66.625199][ C1] irq_exit+0x19b/0x1e0 [ 66.630982][ C1] smp_apic_timer_interrupt+0x1a3/0x610 [ 66.638155][ C1] apic_timer_interrupt+0xf/0x20 [ 66.644719][ C1] native_safe_halt+0xe/0x10 [ 66.650936][ C1] default_enter_idle+0x71/0xf0 [ 66.657432][ C1] cpuidle_enter_state+0xef/0xfb0 [ 66.664093][ C1] cpuidle_enter+0x4f/0xa0 [ 66.670270][ C1] do_idle+0x45f/0x6e0 [ 66.676057][ C1] cpu_startup_entry+0x1b/0x20 [ 66.682495][ C1] start_secondary+0x2f4/0x410 [ 66.688893][ C1] secondary_startup_64+0xa4/0xb0 [ 66.695542][ C1] INITIAL USE at: [ 66.699419][ C1] lock_acquire+0x190/0x410 [ 66.705464][ C1] _raw_spin_lock_irq+0x60/0x80 [ 66.711855][ C1] io_submit_one+0xeb5/0x2ef0 [ 66.718072][ C1] __x64_sys_io_submit+0x1bd/0x570 [ 66.724839][ C1] do_syscall_64+0xfa/0x760 [ 66.730951][ C1] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 66.738385][ C1] } [ 66.740873][ C1] ... key at: [] __key.54358+0x0/0x40 [ 66.748299][ C1] ... acquired at: [ 66.752315][ C1] mark_lock+0x517/0x1220 [ 66.756797][ C1] __lock_acquire+0x1e8e/0x4a00 [ 66.761803][ C1] lock_acquire+0x190/0x410 [ 66.766470][ C1] _raw_spin_lock_irq+0x60/0x80 [ 66.771472][ C1] free_ioctx_users+0x2d/0x490 [ 66.776387][ C1] percpu_ref_switch_to_atomic_rcu+0x4c0/0x570 [ 66.782699][ C1] rcu_core+0x581/0x1560 [ 66.787191][ C1] rcu_core_si+0x9/0x10 [ 66.791501][ C1] __do_softirq+0x262/0x98c [ 66.796163][ C1] irq_exit+0x19b/0x1e0 [ 66.802037][ C1] smp_apic_timer_interrupt+0x1a3/0x610 [ 66.807729][ C1] apic_timer_interrupt+0xf/0x20 [ 66.812815][ C1] native_safe_halt+0xe/0x10 [ 66.817558][ C1] default_enter_idle+0x71/0xf0 [ 66.822556][ C1] cpuidle_enter_state+0xef/0xfb0 [ 66.827733][ C1] cpuidle_enter+0x4f/0xa0 [ 66.832343][ C1] do_idle+0x45f/0x6e0 [ 66.836559][ C1] cpu_startup_entry+0x1b/0x20 [ 66.841474][ C1] start_secondary+0x2f4/0x410 [ 66.846407][ C1] secondary_startup_64+0xa4/0xb0 [ 66.851574][ C1] [ 66.853878][ C1] [ 66.853878][ C1] stack backtrace: [ 66.859790][ C1] CPU: 1 PID: 0 Comm: swapper/1 Not tainted 5.3.0-rc6-next-20190830 #75 [ 66.868084][ C1] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 66.878123][ C1] Call Trace: [ 66.881382][ C1] [ 66.884216][ C1] dump_stack+0x172/0x1f0 [ 66.888521][ C1] print_irq_inversion_bug.part.0+0x2e4/0x2f1 [ 66.894563][ C1] check_usage_forwards.cold+0x20/0x29 [ 66.899995][ C1] ? check_usage_backwards+0x330/0x330 [ 66.905429][ C1] ? save_trace+0x3e/0x8c0 [ 66.909821][ C1] mark_lock+0x517/0x1220 [ 66.914129][ C1] ? check_usage_backwards+0x330/0x330 [ 66.919562][ C1] __lock_acquire+0x1e8e/0x4a00 [ 66.924451][ C1] ? __kasan_check_read+0x11/0x20 [ 66.929477][ C1] ? mark_lock+0xc2/0x1220 [ 66.933883][ C1] ? mark_held_locks+0xf0/0xf0 [ 66.938631][ C1] lock_acquire+0x190/0x410 [ 66.943126][ C1] ? free_ioctx_users+0x2d/0x490 [ 66.948041][ C1] _raw_spin_lock_irq+0x60/0x80 [ 66.952869][ C1] ? free_ioctx_users+0x2d/0x490 [ 66.957783][ C1] free_ioctx_users+0x2d/0x490 [ 66.962523][ C1] ? rcu_dynticks_curr_cpu_in_eqs+0x54/0xb0 [ 66.968566][ C1] percpu_ref_switch_to_atomic_rcu+0x4c0/0x570 [ 66.974718][ C1] ? percpu_ref_exit+0xd0/0xd0 [ 66.979464][ C1] rcu_core+0x581/0x1560 [ 66.983687][ C1] ? __rcu_read_unlock+0x6b0/0x6b0 [ 66.988775][ C1] ? rcu_read_lock_sched_held+0x9c/0xd0 [ 66.994300][ C1] ? rcu_read_lock_any_held.part.0+0x50/0x50 [ 67.000254][ C1] ? run_rebalance_domains+0x227/0x2d0 [ 67.005701][ C1] rcu_core_si+0x9/0x10 [ 67.009846][ C1] __do_softirq+0x262/0x98c [ 67.014324][ C1] ? sched_clock_cpu+0x1b/0x1b0 [ 67.019168][ C1] irq_exit+0x19b/0x1e0 [ 67.023300][ C1] smp_apic_timer_interrupt+0x1a3/0x610 [ 67.028819][ C1] apic_timer_interrupt+0xf/0x20 [ 67.033726][ C1] [ 67.036651][ C1] RIP: 0010:native_safe_halt+0xe/0x10 [ 67.042013][ 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 [ 67.061681][ C1] RSP: 0018:ffff8880a98dfcd0 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff13 [ 67.070068][ C1] RAX: 1ffffffff11e5db7 RBX: 0000000000000000 RCX: 0000000000000000 [ 67.078019][ C1] RDX: dffffc0000000000 RSI: 0000000000000006 RDI: ffff8880a98d0bdc [ 67.085965][ C1] RBP: ffff8880a98dfd00 R08: ffff8880a98d0340 R09: 0000000000000000 [ 67.093933][ C1] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000001 [ 67.101899][ C1] R13: 0000000000000000 R14: 0000000000000060 R15: 0000000000000001 [ 67.109862][ C1] ? default_idle+0x4e/0x360 [ 67.114433][ C1] default_enter_idle+0x71/0xf0 [ 67.119271][ C1] cpuidle_enter_state+0xef/0xfb0 [ 67.124285][ C1] ? __