[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [ 53.056822][ T26] audit: type=1800 audit(1567342897.843:25): pid=8396 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="cron" dev="sda1" ino=2414 res=0 [ 53.102988][ T26] audit: type=1800 audit(1567342897.843:26): pid=8396 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="mcstrans" dev="sda1" ino=2457 res=0 [ 53.134946][ T26] audit: type=1800 audit(1567342897.853:27): pid=8396 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 '10.128.0.2' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 62.644556][ C1] [ 62.646903][ C1] ======================================================== [ 62.654082][ C1] WARNING: possible irq lock inversion dependency detected [ 62.661257][ C1] 5.3.0-rc6-next-20190830 #75 Not tainted [ 62.666981][ C1] -------------------------------------------------------- [ 62.674142][ C1] swapper/1/0 just changed the state of lock: [ 62.680183][ C1] ffff888099ef3b58 (&(&ctx->ctx_lock)->rlock){..-.}, at: free_ioctx_users+0x2d/0x490 [ 62.689615][ C1] but this lock took another, SOFTIRQ-unsafe lock in the past: [ 62.697120][ C1] (&fiq->waitq){+.+.} [ 62.697125][ C1] [ 62.697125][ C1] [ 62.697125][ C1] and interrupts could create inverse lock ordering between them. [ 62.697125][ C1] [ 62.715432][ C1] [ 62.715432][ C1] other info that might help us debug this: [ 62.723461][ C1] Possible interrupt unsafe locking scenario: [ 62.723461][ C1] [ 62.731750][ C1] CPU0 CPU1 [ 62.737088][ C1] ---- ---- [ 62.742422][ C1] lock(&fiq->waitq); [ 62.746460][ C1] local_irq_disable(); [ 62.753184][ C1] lock(&(&ctx->ctx_lock)->rlock); [ 62.760974][ C1] lock(&fiq->waitq); [ 62.767528][ C1] [ 62.770970][ C1] lock(&(&ctx->ctx_lock)->rlock); [ 62.776309][ C1] [ 62.776309][ C1] *** DEADLOCK *** [ 62.776309][ C1] [ 62.784427][ C1] 2 locks held by swapper/1/0: [ 62.789156][ C1] #0: ffffffff88fa7e40 (rcu_callback){....}, at: rcu_core+0x60e/0x1560 [ 62.797457][ C1] #1: ffffffff88fa7e80 (rcu_read_lock_sched){....}, at: percpu_ref_switch_to_atomic_rcu+0x20e/0x570 [ 62.808277][ C1] [ 62.808277][ C1] the shortest dependencies between 2nd lock and 1st lock: [ 62.817614][ C1] -> (&fiq->waitq){+.+.} { [ 62.822087][ C1] HARDIRQ-ON-W at: [ 62.826233][ C1] lock_acquire+0x190/0x410 [ 62.832532][ C1] _raw_spin_lock+0x2f/0x40 [ 62.838831][ C1] flush_bg_queue+0x1f1/0x3b0 [ 62.845303][ C1] fuse_request_queue_background+0x2f8/0x5b0 [ 62.853076][ C1] fuse_request_send_background+0x58/0x110 [ 62.860673][ C1] cuse_channel_open+0x5c3/0x839 [ 62.867407][ C1] misc_open+0x395/0x4c0 [ 62.873443][ C1] chrdev_open+0x245/0x6b0 [ 62.879652][ C1] do_dentry_open+0x4df/0x1250 [ 62.886207][ C1] vfs_open+0xa0/0xd0 [ 62.892069][ C1] path_openat+0x10e9/0x46d0 [ 62.898451][ C1] do_filp_open+0x1a1/0x280 [ 62.904748][ C1] do_sys_open+0x3fe/0x5d0 [ 62.910955][ C1] __x64_sys_openat+0x9d/0x100 [ 62.917533][ C1] do_syscall_64+0xfa/0x760 [ 62.923832][ C1] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 62.931513][ C1] SOFTIRQ-ON-W at: [ 62.935568][ C1] lock_acquire+0x190/0x410 [ 62.941864][ C1] _raw_spin_lock+0x2f/0x40 [ 62.948172][ C1] flush_bg_queue+0x1f1/0x3b0 [ 62.954646][ C1] fuse_request_queue_background+0x2f8/0x5b0 [ 62.962418][ C1] fuse_request_send_background+0x58/0x110 [ 62.970013][ C1] cuse_channel_open+0x5c3/0x839 [ 62.976749][ C1] misc_open+0x395/0x4c0 [ 62.982784][ C1] chrdev_open+0x245/0x6b0 [ 62.988993][ C1] do_dentry_open+0x4df/0x1250 [ 62.995550][ C1] vfs_open+0xa0/0xd0 [ 63.001325][ C1] path_openat+0x10e9/0x46d0 [ 63.007712][ C1] do_filp_open+0x1a1/0x280 [ 63.014005][ C1] do_sys_open+0x3fe/0x5d0 [ 63.020212][ C1] __x64_sys_openat+0x9d/0x100 [ 63.026782][ C1] do_syscall_64+0xfa/0x760 [ 63.033095][ C1] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 63.040785][ C1] INITIAL USE at: [ 63.044754][ C1] lock_acquire+0x190/0x410 [ 63.050964][ C1] _raw_spin_lock+0x2f/0x40 [ 63.057187][ C1] flush_bg_queue+0x1f1/0x3b0 [ 63.063573][ C1] fuse_request_queue_background+0x2f8/0x5b0 [ 63.071258][ C1] fuse_request_send_background+0x58/0x110 [ 63.078770][ C1] cuse_channel_open+0x5c3/0x839 [ 63.085412][ C1] misc_open+0x395/0x4c0 [ 63.091378][ C1] chrdev_open+0x245/0x6b0 [ 63.097505][ C1] do_dentry_open+0x4df/0x1250 [ 63.103971][ C1] vfs_open+0xa0/0xd0 [ 63.109661][ C1] path_openat+0x10e9/0x46d0 [ 63.115959][ C1] do_filp_open+0x1a1/0x280 [ 63.122170][ C1] do_sys_open+0x3fe/0x5d0 [ 63.128294][ C1] __x64_sys_openat+0x9d/0x100 [ 63.134764][ C1] do_syscall_64+0xfa/0x760 [ 63.140993][ C1] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 63.148592][ C1] } [ 63.151157][ C1] ... key at: [] __key.44810+0x0/0x40 [ 63.158662][ C1] ... acquired at: [ 63.162541][ C1] _raw_spin_lock+0x2f/0x40 [ 63.167195][ C1] io_submit_one+0xefa/0x2ef0 [ 63.172036][ C1] __x64_sys_io_submit+0x1bd/0x570 [ 63.177291][ C1] do_syscall_64+0xfa/0x760 [ 63.181938][ C1] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 63.187968][ C1] [ 63.190280][ C1] -> (&(&ctx->ctx_lock)->rlock){..-.} { [ 63.195799][ C1] IN-SOFTIRQ-W at: [ 63.199769][ C1] lock_acquire+0x190/0x410 [ 63.205891][ C1] _raw_spin_lock_irq+0x60/0x80 [ 63.212363][ C1] free_ioctx_users+0x2d/0x490 [ 63.218749][ C1] percpu_ref_switch_to_atomic_rcu+0x4c0/0x570 [ 63.226520][ C1] rcu_core+0x581/0x1560 [ 63.232384][ C1] rcu_core_si+0x9/0x10 [ 63.238157][ C1] __do_softirq+0x262/0x98c [ 63.244278][ C1] irq_exit+0x19b/0x1e0 [ 63.250051][ C1] smp_apic_timer_interrupt+0x1a3/0x610 [ 63.257214][ C1] apic_timer_interrupt+0xf/0x20 [ 63.263769][ C1] native_safe_halt+0xe/0x10 [ 63.269979][ C1] default_enter_idle+0x71/0xf0 [ 63.276448][ C1] cpuidle_enter_state+0xef/0xfb0 [ 63.283091][ C1] cpuidle_enter+0x4f/0xa0 [ 63.289127][ C1] do_idle+0x45f/0x6e0 [ 63.294815][ C1] cpu_startup_entry+0x1b/0x20 [ 63.301201][ C1] start_secondary+0x2f4/0x410 [ 63.307584][ C1] secondary_startup_64+0xa4/0xb0 [ 63.314221][ C1] INITIAL USE at: [ 63.318086][ C1] lock_acquire+0x190/0x410 [ 63.324120][ C1] _raw_spin_lock_irq+0x60/0x80 [ 63.330586][ C1] io_submit_one+0xeb5/0x2ef0 [ 63.336796][ C1] __x64_sys_io_submit+0x1bd/0x570 [ 63.343458][ C1] do_syscall_64+0xfa/0x760 [ 63.349511][ C1] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 63.356933][ C1] } [ 63.359411][ C1] ... key at: [] __key.54358+0x0/0x40 [ 63.366830][ C1] ... acquired at: [ 63.370612][ C1] mark_lock+0x517/0x1220 [ 63.375084][ C1] __lock_acquire+0x1e8e/0x4a00 [ 63.380076][ C1] lock_acquire+0x190/0x410 [ 63.384721][ C1] _raw_spin_lock_irq+0x60/0x80 [ 63.389712][ C1] free_ioctx_users+0x2d/0x490 [ 63.394619][ C1] percpu_ref_switch_to_atomic_rcu+0x4c0/0x570 [ 63.400912][ C1] rcu_core+0x581/0x1560 [ 63.405315][ C1] rcu_core_si+0x9/0x10 [ 63.409616][ C1] __do_softirq+0x262/0x98c [ 63.414259][ C1] irq_exit+0x19b/0x1e0 [ 63.418558][ C1] smp_apic_timer_interrupt+0x1a3/0x610 [ 63.424246][ C1] apic_timer_interrupt+0xf/0x20 [ 63.429340][ C1] native_safe_halt+0xe/0x10 [ 63.434080][ C1] default_enter_idle+0x71/0xf0 [ 63.439073][ C1] cpuidle_enter_state+0xef/0xfb0 [ 63.444240][ C1] cpuidle_enter+0x4f/0xa0 [ 63.448799][ C1] do_idle+0x45f/0x6e0 [ 63.453011][ C1] cpu_startup_entry+0x1b/0x20 [ 63.457918][ C1] start_secondary+0x2f4/0x410 [ 63.462825][ C1] secondary_startup_64+0xa4/0xb0 [ 63.467989][ C1] [ 63.470292][ C1] [ 63.470292][ C1] stack backtrace: [ 63.476182][ C1] CPU: 1 PID: 0 Comm: swapper/1 Not tainted 5.3.0-rc6-next-20190830 #75 [ 63.484474][ C1] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 63.494500][ C1] Call Trace: [ 63.497753][ C1] [ 63.500578][ C1] dump_stack+0x172/0x1f0 [ 63.504878][ C1] print_irq_inversion_bug.part.0+0x2e4/0x2f1 [ 63.510932][ C1] check_usage_forwards.cold+0x20/0x29 [ 63.516370][ C1] ? check_usage_backwards+0x330/0x330 [ 63.521800][ C1] ? save_trace+0x3e/0x8c0 [ 63.526554][ C1] mark_lock+0x517/0x1220 [ 63.530853][ C1] ? check_usage_backwards+0x330/0x330 [ 63.536282][ C1] __lock_acquire+0x1e8e/0x4a00 [ 63.541101][ C1] ? __kasan_check_read+0x11/0x20 [ 63.546094][ C1] ? mark_lock+0xc2/0x1220 [ 63.550480][ C1] ? mark_held_locks+0xf0/0xf0 [ 63.555215][ C1] lock_acquire+0x190/0x410 [ 63.559688][ C1] ? free_ioctx_users+0x2d/0x490 [ 63.564599][ C1] _raw_spin_lock_irq+0x60/0x80 [ 63.569418][ C1] ? free_ioctx_users+0x2d/0x490 [ 63.574339][ C1] free_ioctx_users+0x2d/0x490 [ 63.579081][ C1] ? rcu_dynticks_curr_cpu_in_eqs+0x54/0xb0 [ 63.584969][ C1] percpu_ref_switch_to_atomic_rcu+0x4c0/0x570 [ 63.591094][ C1] ? percpu_ref_exit+0xd0/0xd0 [ 63.595829][ C1] rcu_core+0x581/0x1560 [ 63.600041][ C1] ? __rcu_read_unlock+0x6b0/0x6b0 [ 63.605145][ C1] ? rcu_read_lock_sched_held+0x9c/0xd0 [ 63.610659][ C1] ? rcu_read_lock_any_held.part.0+0x50/0x50 [ 63.616629][ C1] ? run_rebalance_domains+0x227/0x2d0 [ 63.622067][ C1] rcu_core_si+0x9/0x10 [ 63.626195][ C1] __do_softirq+0x262/0x98c [ 63.630680][ C1] ? sched_clock_cpu+0x1b/0x1b0 [ 63.635506][ C1] irq_exit+0x19b/0x1e0 [ 63.639891][ C1] smp_apic_timer_interrupt+0x1a3/0x610 [ 63.645426][ C1] apic_timer_interrupt+0xf/0x20 [ 63.650344][ C1] [ 63.653256][ C1] RIP: 0010:native_safe_halt+0xe/0x10 [ 63.658614][ 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 [ 63.678614][ C1] RSP: 0018:ffff8880a98dfcd0 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff13 [ 63.686994][ C1] RAX: 1ffffffff11e5db7 RBX: 0000000000000000 RCX: 0000000000000000 [ 63.694937][ C1] RDX: dffffc0000000000 RSI: 0000000000000006 RDI: ffff8880a98d0bdc [ 63.702877][ C1] RBP: ffff8880a98dfd00 R08: ffff8880a98d0340 R09: 0000000000000000 [ 63.710823][ C1] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000001 [ 63.718765][ C1] R13: 0000000000000000 R14: 0000000000000060 R15: 0000000000000001 [ 63.726721][ C1] ? default_idle+0x4e/0x360 [ 63.731281][ C1] default_enter_idle+0x71/0xf0 [ 63.736119][ C1] cpuidle_enter_state+0xef/0xfb0 [ 63.741119][ C1] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 63.747350][ C1]