[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [ 54.482193][ T26] audit: type=1800 audit(1567475141.561:25): pid=8483 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="cron" dev="sda1" ino=2414 res=0 [ 54.520234][ T26] audit: type=1800 audit(1567475141.561:26): pid=8483 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="mcstrans" dev="sda1" ino=2457 res=0 [ 54.544323][ T26] audit: type=1800 audit(1567475141.561:27): pid=8483 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 '10.128.1.3' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 62.570201][ C1] [ 62.572549][ C1] ======================================================== [ 62.579711][ C1] WARNING: possible irq lock inversion dependency detected [ 62.586873][ C1] 5.3.0-rc6-next-20190830 #75 Not tainted [ 62.592559][ C1] -------------------------------------------------------- [ 62.599720][ C1] swapper/1/0 just changed the state of lock: [ 62.605753][ C1] ffff8880915adb58 (&(&ctx->ctx_lock)->rlock){..-.}, at: free_ioctx_users+0x2d/0x490 [ 62.615220][ C1] but this lock took another, SOFTIRQ-unsafe lock in the past: [ 62.622728][ C1] (&fiq->waitq){+.+.} [ 62.622734][ C1] [ 62.622734][ C1] [ 62.622734][ C1] and interrupts could create inverse lock ordering between them. [ 62.622734][ C1] [ 62.641040][ C1] [ 62.641040][ C1] other info that might help us debug this: [ 62.649069][ C1] Possible interrupt unsafe locking scenario: [ 62.649069][ C1] [ 62.657353][ C1] CPU0 CPU1 [ 62.662726][ C1] ---- ---- [ 62.668086][ C1] lock(&fiq->waitq); [ 62.672122][ C1] local_irq_disable(); [ 62.678877][ C1] lock(&(&ctx->ctx_lock)->rlock); [ 62.686561][ C1] lock(&fiq->waitq); [ 62.693125][ C1] [ 62.696548][ C1] lock(&(&ctx->ctx_lock)->rlock); [ 62.701888][ C1] [ 62.701888][ C1] *** DEADLOCK *** [ 62.701888][ C1] [ 62.710004][ C1] 2 locks held by swapper/1/0: [ 62.714733][ C1] #0: ffffffff88fa7e40 (rcu_callback){....}, at: rcu_core+0x60e/0x1560 [ 62.723035][ C1] #1: ffffffff88fa7e80 (rcu_read_lock_sched){....}, at: percpu_ref_switch_to_atomic_rcu+0x20e/0x570 [ 62.733857][ C1] [ 62.733857][ C1] the shortest dependencies between 2nd lock and 1st lock: [ 62.743192][ C1] -> (&fiq->waitq){+.+.} { [ 62.747666][ C1] HARDIRQ-ON-W at: [ 62.751709][ C1] lock_acquire+0x190/0x410 [ 62.758008][ C1] _raw_spin_lock+0x2f/0x40 [ 62.764305][ C1] flush_bg_queue+0x1f1/0x3b0 [ 62.770776][ C1] fuse_request_queue_background+0x2f8/0x5b0 [ 62.778555][ C1] fuse_request_send_background+0x58/0x110 [ 62.786164][ C1] cuse_channel_open+0x5c3/0x839 [ 62.792896][ C1] misc_open+0x395/0x4c0 [ 62.798930][ C1] chrdev_open+0x245/0x6b0 [ 62.805139][ C1] do_dentry_open+0x4df/0x1250 [ 62.811694][ C1] vfs_open+0xa0/0xd0 [ 62.817468][ C1] path_openat+0x10e9/0x46d0 [ 62.823849][ C1] do_filp_open+0x1a1/0x280 [ 62.830147][ C1] do_sys_open+0x3fe/0x5d0 [ 62.836365][ C1] __x64_sys_openat+0x9d/0x100 [ 62.842922][ C1] do_syscall_64+0xfa/0x760 [ 62.849225][ C1] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 62.856903][ C1] SOFTIRQ-ON-W at: [ 62.860947][ C1] lock_acquire+0x190/0x410 [ 62.867242][ C1] _raw_spin_lock+0x2f/0x40 [ 62.873539][ C1] flush_bg_queue+0x1f1/0x3b0 [ 62.880006][ C1] fuse_request_queue_background+0x2f8/0x5b0 [ 62.887788][ C1] fuse_request_send_background+0x58/0x110 [ 62.895389][ C1] cuse_channel_open+0x5c3/0x839 [ 62.902119][ C1] misc_open+0x395/0x4c0 [ 62.908152][ C1] chrdev_open+0x245/0x6b0 [ 62.914369][ C1] do_dentry_open+0x4df/0x1250 [ 62.920927][ C1] vfs_open+0xa0/0xd0 [ 62.926701][ C1] path_openat+0x10e9/0x46d0 [ 62.933082][ C1] do_filp_open+0x1a1/0x280 [ 62.939375][ C1] do_sys_open+0x3fe/0x5d0 [ 62.945582][ C1] __x64_sys_openat+0x9d/0x100 [ 62.952138][ C1] do_syscall_64+0xfa/0x760 [ 62.958440][ C1] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 62.966132][ C1] INITIAL USE at: [ 62.970088][ C1] lock_acquire+0x190/0x410 [ 62.976297][ C1] _raw_spin_lock+0x2f/0x40 [ 62.982514][ C1] flush_bg_queue+0x1f1/0x3b0 [ 62.988896][ C1] fuse_request_queue_background+0x2f8/0x5b0 [ 62.996583][ C1] fuse_request_send_background+0x58/0x110 [ 63.004202][ C1] cuse_channel_open+0x5c3/0x839 [ 63.010843][ C1] misc_open+0x395/0x4c0 [ 63.016789][ C1] chrdev_open+0x245/0x6b0 [ 63.022923][ C1] do_dentry_open+0x4df/0x1250 [ 63.029400][ C1] vfs_open+0xa0/0xd0 [ 63.035087][ C1] path_openat+0x10e9/0x46d0 [ 63.041382][ C1] do_filp_open+0x1a1/0x280 [ 63.047600][ C1] do_sys_open+0x3fe/0x5d0 [ 63.053722][ C1] __x64_sys_openat+0x9d/0x100 [ 63.060198][ C1] do_syscall_64+0xfa/0x760 [ 63.066412][ C1] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 63.074008][ C1] } [ 63.076573][ C1] ... key at: [] __key.44810+0x0/0x40 [ 63.084077][ C1] ... acquired at: [ 63.087945][ C1] _raw_spin_lock+0x2f/0x40 [ 63.092592][ C1] io_submit_one+0xefa/0x2ef0 [ 63.097409][ C1] __x64_sys_io_submit+0x1bd/0x570 [ 63.102753][ C1] do_syscall_64+0xfa/0x760 [ 63.107412][ C1] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 63.113453][ C1] [ 63.115750][ C1] -> (&(&ctx->ctx_lock)->rlock){..-.} { [ 63.121268][ C1] IN-SOFTIRQ-W at: [ 63.125311][ C1] lock_acquire+0x190/0x410 [ 63.131438][ C1] _raw_spin_lock_irq+0x60/0x80 [ 63.137916][ C1] free_ioctx_users+0x2d/0x490 [ 63.144303][ C1] percpu_ref_switch_to_atomic_rcu+0x4c0/0x570 [ 63.152072][ C1] rcu_core+0x581/0x1560 [ 63.157930][ C1] rcu_core_si+0x9/0x10 [ 63.163712][ C1] __do_softirq+0x262/0x98c [ 63.169836][ C1] irq_exit+0x19b/0x1e0 [ 63.175620][ C1] smp_apic_timer_interrupt+0x1a3/0x610 [ 63.182782][ C1] apic_timer_interrupt+0xf/0x20 [ 63.189350][ C1] native_safe_halt+0xe/0x10 [ 63.195578][ C1] default_enter_idle+0x71/0xf0 [ 63.202096][ C1] cpuidle_enter_state+0xef/0xfb0 [ 63.208740][ C1] cpuidle_enter+0x4f/0xa0 [ 63.214777][ C1] do_idle+0x45f/0x6e0 [ 63.220466][ C1] cpu_startup_entry+0x1b/0x20 [ 63.226852][ C1] start_secondary+0x2f4/0x410 [ 63.233237][ C1] secondary_startup_64+0xa4/0xb0 [ 63.239875][ C1] INITIAL USE at: [ 63.243744][ C1] lock_acquire+0x190/0x410 [ 63.249781][ C1] _raw_spin_lock_irq+0x60/0x80 [ 63.256166][ C1] io_submit_one+0xeb5/0x2ef0 [ 63.262376][ C1] __x64_sys_io_submit+0x1bd/0x570 [ 63.269023][ C1] do_syscall_64+0xfa/0x760 [ 63.275062][ C1] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 63.282534][ C1] } [ 63.285019][ C1] ... key at: [] __key.54358+0x0/0x40 [ 63.292442][ C1] ... acquired at: [ 63.296227][ C1] mark_lock+0x517/0x1220 [ 63.300708][ C1] __lock_acquire+0x1e8e/0x4a00 [ 63.305703][ C1] lock_acquire+0x190/0x410 [ 63.310352][ C1] _raw_spin_lock_irq+0x60/0x80 [ 63.315347][ C1] free_ioctx_users+0x2d/0x490 [ 63.320259][ C1] percpu_ref_switch_to_atomic_rcu+0x4c0/0x570 [ 63.326556][ C1] rcu_core+0x581/0x1560 [ 63.330940][ C1] rcu_core_si+0x9/0x10 [ 63.335282][ C1] __do_softirq+0x262/0x98c [ 63.339927][ C1] irq_exit+0x19b/0x1e0 [ 63.344228][ C1] smp_apic_timer_interrupt+0x1a3/0x610 [ 63.349915][ C1] apic_timer_interrupt+0xf/0x20 [ 63.354999][ C1] native_safe_halt+0xe/0x10 [ 63.359733][ C1] default_enter_idle+0x71/0xf0 [ 63.364727][ C1] cpuidle_enter_state+0xef/0xfb0 [ 63.369894][ C1] cpuidle_enter+0x4f/0xa0 [ 63.374454][ C1] do_idle+0x45f/0x6e0 [ 63.378666][ C1] cpu_startup_entry+0x1b/0x20 [ 63.383577][ C1] start_secondary+0x2f4/0x410 [ 63.388493][ C1] secondary_startup_64+0xa4/0xb0 [ 63.393658][ C1] [ 63.395963][ C1] [ 63.395963][ C1] stack backtrace: [ 63.401836][ C1] CPU: 1 PID: 0 Comm: swapper/1 Not tainted 5.3.0-rc6-next-20190830 #75 [ 63.410126][ C1] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 63.420158][ C1] Call Trace: [ 63.423426][ C1] [ 63.426256][ C1] dump_stack+0x172/0x1f0 [ 63.430560][ C1] print_irq_inversion_bug.part.0+0x2e4/0x2f1 [ 63.436596][ C1] check_usage_forwards.cold+0x20/0x29 [ 63.442027][ C1] ? check_usage_backwards+0x330/0x330 [ 63.447459][ C1] ? save_trace+0x3e/0x8c0 [ 63.451853][ C1] mark_lock+0x517/0x1220 [ 63.456155][ C1] ? check_usage_backwards+0x330/0x330 [ 63.461604][ C1] __lock_acquire+0x1e8e/0x4a00 [ 63.466429][ C1] ? __kasan_check_read+0x11/0x20 [ 63.471426][ C1] ? mark_lock+0xc2/0x1220 [ 63.475815][ C1] ? mark_held_locks+0xf0/0xf0 [ 63.480551][ C1] lock_acquire+0x190/0x410 [ 63.485029][ C1] ? free_ioctx_users+0x2d/0x490 [ 63.489938][ C1] _raw_spin_lock_irq+0x60/0x80 [ 63.494757][ C1] ? free_ioctx_users+0x2d/0x490 [ 63.499664][ C1] free_ioctx_users+0x2d/0x490 [ 63.504400][ C1] ? rcu_dynticks_curr_cpu_in_eqs+0x54/0xb0 [ 63.510282][ C1] percpu_ref_switch_to_atomic_rcu+0x4c0/0x570 [ 63.516406][ C1] ? percpu_ref_exit+0xd0/0xd0 [ 63.521145][ C1] rcu_core+0x581/0x1560 [ 63.525358][ C1] ? __rcu_read_unlock+0x6b0/0x6b0 [ 63.530441][ C1] ? rcu_read_lock_sched_held+0x9c/0xd0 [ 63.535955][ C1] ? rcu_read_lock_any_held.part.0+0x50/0x50 [ 63.541907][ C1] ? run_rebalance_domains+0x227/0x2d0 [ 63.547335][ C1] rcu_core_si+0x9/0x10 [ 63.551461][ C1] __do_softirq+0x262/0x98c [ 63.555933][ C1] ? sched_clock_cpu+0x1b/0x1b0 [ 63.560760][ C1] irq_exit+0x19b/0x1e0 [ 63.564889][ C1] smp_apic_timer_interrupt+0x1a3/0x610 [ 63.570403][ C1] apic_timer_interrupt+0xf/0x20 [ 63.575308][ C1] [ 63.578229][ C1] RIP: 0010:native_safe_halt+0xe/0x10 [ 63.583587][ 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 [ 63.604559][ C1] RSP: 0018:ffff8880a98dfcd0 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff13 [ 63.612946][ C1] RAX: 1ffffffff11e5db7 RBX: 0000000000000000 RCX: 0000000000000000 [ 63.620888][ C1] RDX: dffffc0000000000 RSI: 0000000000000006 RDI: ffff8880a98d0bdc [ 63.628839][ C1] RBP: ffff8880a98dfd00 R08: ffff8880a98d0340 R09: 0000000000000000 [ 63.636782][ C1] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000001 [ 63.644723][ C1] R13: 0000000000000000 R14: 0000000000000060 R15: 0000000000000001 [ 63.652678][ C1] ? default_idle+0x4e/0x360 [ 63.657243][ C1] default_enter_idle+0x71/0xf0 [ 63.662076][ C1] cpuidle_enter_state+0xef/0xfb0 [ 63.667073][ C1] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 63.673282][ C1