[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [ 53.127655][ T26] audit: type=1800 audit(1567237813.048:25): pid=8448 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="cron" dev="sda1" ino=2414 res=0 [ 53.164908][ T26] audit: type=1800 audit(1567237813.048:26): pid=8448 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="mcstrans" dev="sda1" ino=2457 res=0 [ 53.199457][ T26] audit: type=1800 audit(1567237813.048:27): pid=8448 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 '10.128.0.180' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 65.636877][ C0] [ 65.639231][ C0] ======================================================== [ 65.646391][ C0] WARNING: possible irq lock inversion dependency detected [ 65.653562][ C0] 5.3.0-rc6-next-20190827 #74 Not tainted [ 65.659244][ C0] -------------------------------------------------------- [ 65.666412][ C0] swapper/0/0 just changed the state of lock: [ 65.672493][ C0] ffff8880a4531b58 (&(&ctx->ctx_lock)->rlock){..-.}, at: free_ioctx_users+0x2d/0x490 [ 65.682070][ C0] but this lock took another, SOFTIRQ-unsafe lock in the past: [ 65.689573][ C0] (&fiq->waitq){+.+.} [ 65.689578][ C0] [ 65.689578][ C0] [ 65.689578][ C0] and interrupts could create inverse lock ordering between them. [ 65.689578][ C0] [ 65.707877][ C0] [ 65.707877][ C0] other info that might help us debug this: [ 65.716070][ C0] Possible interrupt unsafe locking scenario: [ 65.716070][ C0] [ 65.724368][ C0] CPU0 CPU1 [ 65.729721][ C0] ---- ---- [ 65.735055][ C0] lock(&fiq->waitq); [ 65.739091][ C0] local_irq_disable(); [ 65.745863][ C0] lock(&(&ctx->ctx_lock)->rlock); [ 65.753567][ C0] lock(&fiq->waitq); [ 65.760122][ C0] [ 65.763550][ C0] lock(&(&ctx->ctx_lock)->rlock); [ 65.768889][ C0] [ 65.768889][ C0] *** DEADLOCK *** [ 65.768889][ C0] [ 65.777024][ C0] 2 locks held by swapper/0/0: [ 65.781751][ C0] #0: ffffffff88fa7e40 (rcu_callback){....}, at: rcu_core+0x60e/0x1560 [ 65.790055][ C0] #1: ffffffff88fa7e80 (rcu_read_lock_sched){....}, at: percpu_ref_switch_to_atomic_rcu+0x20e/0x570 [ 65.800874][ C0] [ 65.800874][ C0] the shortest dependencies between 2nd lock and 1st lock: [ 65.810214][ C0] -> (&fiq->waitq){+.+.} { [ 65.814683][ C0] HARDIRQ-ON-W at: [ 65.818719][ C0] lock_acquire+0x190/0x410 [ 65.825012][ C0] _raw_spin_lock+0x2f/0x40 [ 65.831426][ C0] flush_bg_queue+0x1f3/0x3c0 [ 65.837913][ C0] fuse_request_queue_background+0x2f8/0x5b0 [ 65.845697][ C0] fuse_request_send_background+0x58/0x110 [ 65.853300][ C0] cuse_channel_open+0x5ba/0x830 [ 65.860116][ C0] misc_open+0x395/0x4c0 [ 65.866207][ C0] chrdev_open+0x245/0x6b0 [ 65.872430][ C0] do_dentry_open+0x4df/0x1250 [ 65.878987][ C0] vfs_open+0xa0/0xd0 [ 65.884935][ C0] path_openat+0x10e9/0x46d0 [ 65.891319][ C0] do_filp_open+0x1a1/0x280 [ 65.897614][ C0] do_sys_open+0x3fe/0x5d0 [ 65.903827][ C0] __x64_sys_openat+0x9d/0x100 [ 65.910398][ C0] do_syscall_64+0xfa/0x760 [ 65.916730][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 65.924412][ C0] SOFTIRQ-ON-W at: [ 65.928457][ C0] lock_acquire+0x190/0x410 [ 65.934770][ C0] _raw_spin_lock+0x2f/0x40 [ 65.941075][ C0] flush_bg_queue+0x1f3/0x3c0 [ 65.947689][ C0] fuse_request_queue_background+0x2f8/0x5b0 [ 65.955632][ C0] fuse_request_send_background+0x58/0x110 [ 65.963380][ C0] cuse_channel_open+0x5ba/0x830 [ 65.970110][ C0] misc_open+0x395/0x4c0 [ 65.976144][ C0] chrdev_open+0x245/0x6b0 [ 65.982370][ C0] do_dentry_open+0x4df/0x1250 [ 65.988924][ C0] vfs_open+0xa0/0xd0 [ 65.994696][ C0] path_openat+0x10e9/0x46d0 [ 66.001078][ C0] do_filp_open+0x1a1/0x280 [ 66.007379][ C0] do_sys_open+0x3fe/0x5d0 [ 66.013596][ C0] __x64_sys_openat+0x9d/0x100 [ 66.020151][ C0] do_syscall_64+0xfa/0x760 [ 66.026444][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 66.034124][ C0] INITIAL USE at: [ 66.038244][ C0] lock_acquire+0x190/0x410 [ 66.044487][ C0] _raw_spin_lock+0x2f/0x40 [ 66.050700][ C0] flush_bg_queue+0x1f3/0x3c0 [ 66.057083][ C0] fuse_request_queue_background+0x2f8/0x5b0 [ 66.064785][ C0] fuse_request_send_background+0x58/0x110 [ 66.072416][ C0] cuse_channel_open+0x5ba/0x830 [ 66.079069][ C0] misc_open+0x395/0x4c0 [ 66.085021][ C0] chrdev_open+0x245/0x6b0 [ 66.091147][ C0] do_dentry_open+0x4df/0x1250 [ 66.097614][ C0] vfs_open+0xa0/0xd0 [ 66.103301][ C0] path_openat+0x10e9/0x46d0 [ 66.109598][ C0] do_filp_open+0x1a1/0x280 [ 66.115811][ C0] do_sys_open+0x3fe/0x5d0 [ 66.121933][ C0] __x64_sys_openat+0x9d/0x100 [ 66.128414][ C0] do_syscall_64+0xfa/0x760 [ 66.134624][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 66.142224][ C0] } [ 66.144795][ C0] ... key at: [] __key.45870+0x0/0x40 [ 66.152306][ C0] ... acquired at: [ 66.156189][ C0] _raw_spin_lock+0x2f/0x40 [ 66.160835][ C0] io_submit_one+0xefa/0x2ef0 [ 66.165651][ C0] __x64_sys_io_submit+0x1bd/0x570 [ 66.170923][ C0] do_syscall_64+0xfa/0x760 [ 66.175637][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 66.181693][ C0] [ 66.183993][ C0] -> (&(&ctx->ctx_lock)->rlock){..-.} { [ 66.189509][ C0] IN-SOFTIRQ-W at: [ 66.193481][ C0] lock_acquire+0x190/0x410 [ 66.199605][ C0] _raw_spin_lock_irq+0x60/0x80 [ 66.206076][ C0] free_ioctx_users+0x2d/0x490 [ 66.212458][ C0] percpu_ref_switch_to_atomic_rcu+0x4c0/0x570 [ 66.220397][ C0] rcu_core+0x581/0x1560 [ 66.226277][ C0] rcu_core_si+0x9/0x10 [ 66.232062][ C0] __do_softirq+0x262/0x98c [ 66.238185][ C0] irq_exit+0x19b/0x1e0 [ 66.243966][ C0] smp_apic_timer_interrupt+0x1a3/0x610 [ 66.251135][ C0] apic_timer_interrupt+0xf/0x20 [ 66.257689][ C0] native_safe_halt+0xe/0x10 [ 66.263917][ C0] default_enter_idle+0x71/0xf0 [ 66.270401][ C0] cpuidle_enter_state+0xef/0xfb0 [ 66.277044][ C0] cpuidle_enter+0x4f/0xa0 [ 66.283212][ C0] do_idle+0x45f/0x6e0 [ 66.288908][ C0] cpu_startup_entry+0x1b/0x20 [ 66.295292][ C0] rest_init+0x245/0x37b [ 66.301152][ C0] arch_call_rest_init+0xe/0x1b [ 66.307618][ C0] start_kernel+0x904/0x943 [ 66.313738][ C0] x86_64_start_reservations+0x29/0x2b [ 66.320958][ C0] x86_64_start_kernel+0x77/0x7b [ 66.327522][ C0] secondary_startup_64+0xa4/0xb0 [ 66.334165][ C0] INITIAL USE at: [ 66.338035][ C0] lock_acquire+0x190/0x410 [ 66.344068][ C0] _raw_spin_lock_irq+0x60/0x80 [ 66.350450][ C0] io_submit_one+0xeb5/0x2ef0 [ 66.356848][ C0] __x64_sys_io_submit+0x1bd/0x570 [ 66.363494][ C0] do_syscall_64+0xfa/0x760 [ 66.369552][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 66.377418][ C0] } [ 66.379896][ C0] ... key at: [] __key.54388+0x0/0x40 [ 66.387316][ C0] ... acquired at: [ 66.391237][ C0] mark_lock+0x517/0x1220 [ 66.395728][ C0] __lock_acquire+0x1e8e/0x4a00 [ 66.400726][ C0] lock_acquire+0x190/0x410 [ 66.405372][ C0] _raw_spin_lock_irq+0x60/0x80 [ 66.410372][ C0] free_ioctx_users+0x2d/0x490 [ 66.415284][ C0] percpu_ref_switch_to_atomic_rcu+0x4c0/0x570 [ 66.421578][ C0] rcu_core+0x581/0x1560 [ 66.425963][ C0] rcu_core_si+0x9/0x10 [ 66.430264][ C0] __do_softirq+0x262/0x98c [ 66.434919][ C0] irq_exit+0x19b/0x1e0 [ 66.439214][ C0] smp_apic_timer_interrupt+0x1a3/0x610 [ 66.444989][ C0] apic_timer_interrupt+0xf/0x20 [ 66.450068][ C0] native_safe_halt+0xe/0x10 [ 66.455239][ C0] default_enter_idle+0x71/0xf0 [ 66.460230][ C0] cpuidle_enter_state+0xef/0xfb0 [ 66.465505][ C0] cpuidle_enter+0x4f/0xa0 [ 66.470076][ C0] do_idle+0x45f/0x6e0 [ 66.474286][ C0] cpu_startup_entry+0x1b/0x20 [ 66.479197][ C0] rest_init+0x245/0x37b [ 66.483599][ C0] arch_call_rest_init+0xe/0x1b [ 66.488591][ C0] start_kernel+0x904/0x943 [ 66.493235][ C0] x86_64_start_reservations+0x29/0x2b [ 66.498832][ C0] x86_64_start_kernel+0x77/0x7b [ 66.503909][ C0] secondary_startup_64+0xa4/0xb0 [ 66.509071][ C0] [ 66.511377][ C0] [ 66.511377][ C0] stack backtrace: [ 66.517238][ C0] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.3.0-rc6-next-20190827 #74 [ 66.525580][ C0] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 66.535742][ C0] Call Trace: [ 66.538997][ C0] [ 66.541822][ C0] dump_stack+0x172/0x1f0 [ 66.546254][ C0] print_irq_inversion_bug.part.0+0x2e4/0x2f1 [ 66.552297][ C0] check_usage_forwards.cold+0x20/0x29 [ 66.557732][ C0] ? check_usage_backwards+0x330/0x330 [ 66.563300][ C0] ? save_trace+0x3e/0x8c0 [ 66.567696][ C0] mark_lock+0x517/0x1220 [ 66.571994][ C0] ? check_usage_backwards+0x330/0x330 [ 66.577425][ C0] __lock_acquire+0x1e8e/0x4a00 [ 66.582248][ C0] ? __kasan_check_read+0x11/0x20 [ 66.587243][ C0] ? mark_lock+0xc2/0x1220 [ 66.591645][ C0] ? mark_held_locks+0xf0/0xf0 [ 66.596385][ C0] lock_acquire+0x190/0x410 [ 66.600861][ C0] ? free_ioctx_users+0x2d/0x490 [ 66.605777][ C0] _raw_spin_lock_irq+0x60/0x80 [ 66.610615][ C0] ? free_ioctx_users+0x2d/0x490 [ 66.615521][ C0] free_ioctx_users+0x2d/0x490 [ 66.620255][ C0] ? rcu_dynticks_curr_cpu_in_eqs+0x54/0xb0 [ 66.626118][ C0] percpu_ref_switch_to_atomic_rcu+0x4c0/0x570 [ 66.632264][ C0] ? percpu_ref_exit+0xd0/0xd0 [ 66.637010][ C0] rcu_core+0x581/0x1560 [ 66.641221][ C0] ? __rcu_read_unlock+0x6b0/0x6b0 [ 66.646301][ C0] ? rcu_read_lock_sched_held+0x9c/0xd0 [ 66.651815][ C0] ? rcu_read_lock_any_held.part.0+0x50/0x50 [ 66.657761][ C0] rcu_core_si+0x9/0x10 [ 66.661888][ C0] __do_softirq+0x262/0x98c [ 66.666366][ C0] ? sched_clock_cpu+0x1b/0x1b0 [ 66.671188][ C0] irq_exit+0x19b/0x1e0 [ 66.675313][ C0] smp_apic_timer_interrupt+0x1a3/0x610 [ 66.680828][ C0] apic_timer_interrupt+0xf/0x20 [ 66.685729][ C0] [ 66.688636][ C0] RIP: 0010:native_safe_halt+0xe/0x10 [ 66.693992][ C0] Code: 78 26 6a fa eb 8a 90 90 90 90 90 90 e9 07 00 00 00 0f 00 2d 04 3e 65 00 f4 c3 66 90 e9 07 00 00 00 0f 00 2d f4 3d 65 00 fb f4 90 55 48 89 e5 41 57 41 56 41 55 41 54 53 e8 2e 07 1d fa e8 29 [ 66.713561][ C0] RSP: 0018:ffffffff88e07c50 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff13 [ 66.721937][ C0] RAX: 1ffffffff11e5daf RBX: 0000000000000000 RCX: 0000000000000000 [ 66.729880][ C0] RDX: dffffc0000000000 RSI: 0000000000000006 RDI: ffffffff88e7aa1c [ 66.737820][ C0] RBP: ffffffff88e07c80 R08: ffffffff88e7a180 R09: 0000000000000000 [ 66.745757][ C0] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000001 [ 66.753693][ C0] R13: 0000000000000000 R14: 0000000000000060 R15: 0000000000000001 [ 66.761642][ C0] ? default_idle+0x4e/0x360 [ 66.766200][ C0] default_enter_idle+0x71/0xf0 [ 66.771017][ C0] cpuidle_enter_state+0xef/0xfb0 [ 66.776011][ C0] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 66.782249][ C0] cpuidle_enter+0x4f/0xa0 [ 66.786664][ C0] do_idle+0x45f/0x6e0 [ 66.790721][ C0] ? arch_cpu_idle_exit+0x80/0x80 [ 66.795717][ C0] ? trace_hardirqs_off+0x1b0/0x240 [ 66.801020][ C0] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 66.807238][ C0] ? debug_smp_processor_id+0x3c/0x214 [ 66.812671][ C0] cpu_startup_entry+0x1b/0x20 [ 66.817409][ C0] rest_init+0x245/0x37b [ 66.821626][ C0] arch_call_rest_init+0xe/0x1b [ 66.826447][ C0] start_kernel+0x904/0x943 [ 66.830924][ C0] ? mem_encrypt_init+0xb/0xb [ 66.835577][ C0] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 66