[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [ 53.734775][ T27] audit: type=1800 audit(1568169227.536:25): pid=8502 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="cron" dev="sda1" ino=2414 res=0 [ 53.756318][ T27] audit: type=1800 audit(1568169227.536:26): pid=8502 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="mcstrans" dev="sda1" ino=2457 res=0 [ 53.795503][ T27] audit: type=1800 audit(1568169227.546:27): pid=8502 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 '10.128.0.176' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 63.240821][ C0] [ 63.243309][ C0] ======================================================== [ 63.250648][ C0] WARNING: possible irq lock inversion dependency detected [ 63.257951][ C0] 5.3.0-rc6-next-20190830 #75 Not tainted [ 63.263652][ C0] -------------------------------------------------------- [ 63.270971][ C0] swapper/0/0 just changed the state of lock: [ 63.277022][ C0] ffff88809c365b58 (&(&ctx->ctx_lock)->rlock){..-.}, at: free_ioctx_users+0x2d/0x490 [ 63.287058][ C0] but this lock took another, SOFTIRQ-unsafe lock in the past: [ 63.294672][ C0] (&fiq->waitq){+.+.} [ 63.294680][ C0] [ 63.294680][ C0] [ 63.294680][ C0] and interrupts could create inverse lock ordering between them. [ 63.294680][ C0] [ 63.313139][ C0] [ 63.313139][ C0] other info that might help us debug this: [ 63.321355][ C0] Possible interrupt unsafe locking scenario: [ 63.321355][ C0] [ 63.329780][ C0] CPU0 CPU1 [ 63.335136][ C0] ---- ---- [ 63.340612][ C0] lock(&fiq->waitq); [ 63.344846][ C0] local_irq_disable(); [ 63.351758][ C0] lock(&(&ctx->ctx_lock)->rlock); [ 63.359587][ C0] lock(&fiq->waitq); [ 63.366486][ C0] [ 63.370093][ C0] lock(&(&ctx->ctx_lock)->rlock); [ 63.376018][ C0] [ 63.376018][ C0] *** DEADLOCK *** [ 63.376018][ C0] [ 63.384538][ C0] 2 locks held by swapper/0/0: [ 63.389469][ C0] #0: ffffffff88fa7e40 (rcu_callback){....}, at: rcu_core+0x60e/0x1560 [ 63.398286][ C0] #1: ffffffff88fa7e80 (rcu_read_lock_sched){....}, at: percpu_ref_switch_to_atomic_rcu+0x20e/0x570 [ 63.410319][ C0] [ 63.410319][ C0] the shortest dependencies between 2nd lock and 1st lock: [ 63.419911][ C0] -> (&fiq->waitq){+.+.} { [ 63.424997][ C0] HARDIRQ-ON-W at: [ 63.429259][ C0] lock_acquire+0x190/0x410 [ 63.436010][ C0] _raw_spin_lock+0x2f/0x40 [ 63.442457][ C0] flush_bg_queue+0x1f1/0x3b0 [ 63.449420][ C0] fuse_request_queue_background+0x2f8/0x5b0 [ 63.457927][ C0] fuse_request_send_background+0x58/0x110 [ 63.465840][ C0] cuse_channel_open+0x5c3/0x839 [ 63.473909][ C0] misc_open+0x395/0x4c0 [ 63.480721][ C0] chrdev_open+0x245/0x6b0 [ 63.488126][ C0] do_dentry_open+0x4df/0x1250 [ 63.495435][ C0] vfs_open+0xa0/0xd0 [ 63.501539][ C0] path_openat+0x10e9/0x46d0 [ 63.507942][ C0] do_filp_open+0x1a1/0x280 [ 63.514494][ C0] do_sys_open+0x3fe/0x5d0 [ 63.521018][ C0] __x64_sys_openat+0x9d/0x100 [ 63.527770][ C0] do_syscall_64+0xfa/0x760 [ 63.534558][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 63.542570][ C0] SOFTIRQ-ON-W at: [ 63.546738][ C0] lock_acquire+0x190/0x410 [ 63.553109][ C0] _raw_spin_lock+0x2f/0x40 [ 63.559772][ C0] flush_bg_queue+0x1f1/0x3b0 [ 63.566932][ C0] fuse_request_queue_background+0x2f8/0x5b0 [ 63.574815][ C0] fuse_request_send_background+0x58/0x110 [ 63.582674][ C0] cuse_channel_open+0x5c3/0x839 [ 63.589825][ C0] misc_open+0x395/0x4c0 [ 63.596721][ C0] chrdev_open+0x245/0x6b0 [ 63.604734][ C0] do_dentry_open+0x4df/0x1250 [ 63.611867][ C0] vfs_open+0xa0/0xd0 [ 63.617976][ C0] path_openat+0x10e9/0x46d0 [ 63.624611][ C0] do_filp_open+0x1a1/0x280 [ 63.631075][ C0] do_sys_open+0x3fe/0x5d0 [ 63.637389][ C0] __x64_sys_openat+0x9d/0x100 [ 63.644143][ C0] do_syscall_64+0xfa/0x760 [ 63.650493][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 63.658243][ C0] INITIAL USE at: [ 63.662686][ C0] lock_acquire+0x190/0x410 [ 63.669231][ C0] _raw_spin_lock+0x2f/0x40 [ 63.675576][ C0] flush_bg_queue+0x1f1/0x3b0 [ 63.681977][ C0] fuse_request_queue_background+0x2f8/0x5b0 [ 63.689859][ C0] fuse_request_send_background+0x58/0x110 [ 63.702126][ C0] cuse_channel_open+0x5c3/0x839 [ 63.709748][ C0] misc_open+0x395/0x4c0 [ 63.716234][ C0] chrdev_open+0x245/0x6b0 [ 63.724012][ C0] do_dentry_open+0x4df/0x1250 [ 63.731211][ C0] vfs_open+0xa0/0xd0 [ 63.737444][ C0] path_openat+0x10e9/0x46d0 [ 63.744143][ C0] do_filp_open+0x1a1/0x280 [ 63.750601][ C0] do_sys_open+0x3fe/0x5d0 [ 63.757565][ C0] __x64_sys_openat+0x9d/0x100 [ 63.764382][ C0] do_syscall_64+0xfa/0x760 [ 63.771578][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 63.780606][ C0] } [ 63.783460][ C0] ... key at: [] __key.44810+0x0/0x40 [ 63.791807][ C0] ... acquired at: [ 63.796037][ C0] _raw_spin_lock+0x2f/0x40 [ 63.801603][ C0] io_submit_one+0xefa/0x2ef0 [ 63.806913][ C0] __x64_sys_io_submit+0x1bd/0x570 [ 63.812475][ C0] do_syscall_64+0xfa/0x760 [ 63.817360][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 63.823662][ C0] [ 63.826173][ C0] -> (&(&ctx->ctx_lock)->rlock){..-.} { [ 63.832384][ C0] IN-SOFTIRQ-W at: [ 63.836977][ C0] lock_acquire+0x190/0x410 [ 63.843793][ C0] _raw_spin_lock_irq+0x60/0x80 [ 63.850448][ C0] free_ioctx_users+0x2d/0x490 [ 63.857514][ C0] percpu_ref_switch_to_atomic_rcu+0x4c0/0x570 [ 63.865783][ C0] rcu_core+0x581/0x1560 [ 63.871847][ C0] rcu_core_si+0x9/0x10 [ 63.878231][ C0] __do_softirq+0x262/0x98c [ 63.884911][ C0] irq_exit+0x19b/0x1e0 [ 63.891017][ C0] smp_apic_timer_interrupt+0x1a3/0x610 [ 63.898857][ C0] apic_timer_interrupt+0xf/0x20 [ 63.906245][ C0] native_safe_halt+0xe/0x10 [ 63.912775][ C0] default_enter_idle+0x71/0xf0 [ 63.919964][ C0] cpuidle_enter_state+0xef/0xfb0 [ 63.927067][ C0] cpuidle_enter+0x4f/0xa0 [ 63.933389][ C0] do_idle+0x45f/0x6e0 [ 63.939980][ C0] cpu_startup_entry+0x1b/0x20 [ 63.946652][ C0] rest_init+0x245/0x37b [ 63.952729][ C0] arch_call_rest_init+0xe/0x1b [ 63.959526][ C0] start_kernel+0x904/0x943 [ 63.966454][ C0] x86_64_start_reservations+0x29/0x2b [ 63.973739][ C0] x86_64_start_kernel+0x77/0x7b [ 63.980825][ C0] secondary_startup_64+0xa4/0xb0 [ 63.988225][ C0] INITIAL USE at: [ 63.992169][ C0] lock_acquire+0x190/0x410 [ 63.999090][ C0] _raw_spin_lock_irq+0x60/0x80 [ 64.008308][ C0] io_submit_one+0xeb5/0x2ef0 [ 64.015500][ C0] __x64_sys_io_submit+0x1bd/0x570 [ 64.024296][ C0] do_syscall_64+0xfa/0x760 [ 64.030624][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 64.038618][ C0] } [ 64.041466][ C0] ... key at: [] __key.54358+0x0/0x40 [ 64.049349][ C0] ... acquired at: [ 64.053628][ C0] mark_lock+0x517/0x1220 [ 64.059193][ C0] __lock_acquire+0x1e8e/0x4a00 [ 64.064498][ C0] lock_acquire+0x190/0x410 [ 64.069942][ C0] _raw_spin_lock_irq+0x60/0x80 [ 64.076277][ C0] free_ioctx_users+0x2d/0x490 [ 64.081433][ C0] percpu_ref_switch_to_atomic_rcu+0x4c0/0x570 [ 64.088414][ C0] rcu_core+0x581/0x1560 [ 64.093519][ C0] rcu_core_si+0x9/0x10 [ 64.098561][ C0] __do_softirq+0x262/0x98c [ 64.117587][ C0] irq_exit+0x19b/0x1e0 [ 64.125810][ C0] smp_apic_timer_interrupt+0x1a3/0x610 [ 64.132703][ C0] apic_timer_interrupt+0xf/0x20 [ 64.137804][ C0] native_safe_halt+0xe/0x10 [ 64.142911][ C0] default_enter_idle+0x71/0xf0 [ 64.149058][ C0] cpuidle_enter_state+0xef/0xfb0 [ 64.155985][ C0] cpuidle_enter+0x4f/0xa0 [ 64.160939][ C0] do_idle+0x45f/0x6e0 [ 64.165217][ C0] cpu_startup_entry+0x1b/0x20 [ 64.170189][ C0] rest_init+0x245/0x37b [ 64.174978][ C0] arch_call_rest_init+0xe/0x1b [ 64.180422][ C0] start_kernel+0x904/0x943 [ 64.185359][ C0] x86_64_start_reservations+0x29/0x2b [ 64.191574][ C0] x86_64_start_kernel+0x77/0x7b [ 64.197490][ C0] secondary_startup_64+0xa4/0xb0 [ 64.204164][ C0] [ 64.206769][ C0] [ 64.206769][ C0] stack backtrace: [ 64.212873][ C0] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.3.0-rc6-next-20190830 #75 [ 64.221783][ C0] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 64.232589][ C0] Call Trace: [ 64.235859][ C0] [ 64.238884][ C0] dump_stack+0x172/0x1f0 [ 64.243323][ C0] print_irq_inversion_bug.part.0+0x2e4/0x2f1 [ 64.249863][ C0] check_usage_forwards.cold+0x20/0x29 [ 64.255613][ C0] ? check_usage_backwards+0x330/0x330 [ 64.261188][ C0] ? save_trace+0x3e/0x8c0 [ 64.265854][ C0] mark_lock+0x517/0x1220 [ 64.270292][ C0] ? check_usage_backwards+0x330/0x330 [ 64.276548][ C0] __lock_acquire+0x1e8e/0x4a00 [ 64.281579][ C0] ? __kasan_check_read+0x11/0x20 [ 64.287253][ C0] ? mark_lock+0xc2/0x1220 [ 64.292384][ C0] ? mark_held_locks+0xf0/0xf0 [ 64.297632][ C0] lock_acquire+0x190/0x410 [ 64.302212][ C0] ? free_ioctx_users+0x2d/0x490 [ 64.308770][ C0] _raw_spin_lock_irq+0x60/0x80 [ 64.314006][ C0] ? free_ioctx_users+0x2d/0x490 [ 64.320071][ C0] free_ioctx_users+0x2d/0x490 [ 64.325031][ C0] ? rcu_dynticks_curr_cpu_in_eqs+0x54/0xb0 [ 64.331611][ C0] percpu_ref_switch_to_atomic_rcu+0x4c0/0x570 [ 64.338482][ C0] ? percpu_ref_exit+0xd0/0xd0 [ 64.344572][ C0] rcu_core+0x581/0x1560 [ 64.349069][ C0] ? __rcu_read_unlock+0x6b0/0x6b0 [ 64.354482][ C0] ? rcu_read_lock_sched_held+0x9c/0xd0 [ 64.360683][ C0] ? rcu_read_lock_any_held.part.0+0x50/0x50 [ 64.366899][ C0] ? run_rebalance_domains+0x227/0x2d0 [ 64.372474][ C0] rcu_core_si+0x9/0x10 [ 64.376651][ C0] __do_softirq+0x262/0x98c [ 64.381957][ C0] ? sched_clock_cpu+0x1b/0x1b0 [ 64.387352][ C0] irq_exit+0x19b/0x1e0 [ 64.391498][ C0] smp_apic_timer_interrupt+0x1a3/0x610 [ 64.397134][ C0] apic_timer_interrupt+0xf/0x20 [ 64.402612][ C0] [ 64.406843][ C0] RIP: 0010:native_safe_halt+0xe/0x10 [ 64.413386][ 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 [ 64.435842][ C0] RSP: 0018:ffffffff88e07c50 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff13 [ 64.444804][ C0] RAX: 1ffffffff11e5db7 RBX: 0000000000000000 RCX: 0000000000000000 [ 64.453375][ C0] RDX: dffffc0000000000 RSI: 0000000000000006 RDI: ffffffff88e7aa1c [ 64.461923][ C0] RBP: ffffffff88e07c80 R08: ffffffff88e7a180 R09: 0000000000000000 [ 64.470497][ C0] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000001 [ 64.479892][ C0] R13: 0000000000000000 R14: 0000000000000060 R15: 0000000000000001 [ 64.489240][ C0] ? default_idle+0x4e/0x360 [ 64.494485][ C0] default_enter_idle+0x71/0xf0 [ 64.499877][ C0] cpuidle_enter_state+0xef/0xfb0 [ 64.505039][ C0] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 64.511450][ C0] cpuidle_enter+0x4f/0xa0 [ 64.515863][ C0] do_idle+0x45f/0x6e0 [ 64.519913][ C0] ? arch_cpu_idle_exit+0x80/0x80 [ 64.525040][ C0] ? trace_hardirqs_on+0x30/0x240 [ 64.530496][ C0] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 64.538003][ C0] ? debug_smp_processor_id+0x3c/0x214 [ 64.544415][ C0] cpu_startup_entry+0x1b/0x20 [ 64.549437][ C0] rest_init+0x245/0x37b [ 64.554092][ C0] arch_call_rest_init+0xe/0x1b [ 64.559058][ C0] start_kernel+0x904/0x943 [ 64.563868][ C0] ? mem_encrypt_init+0xb/0xb [ 64.568754][ C0] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 64.575549][ C0] ? x86_family+0x41/0x50 [ 64.580503][ C0] ? __sanitizer_cov_trace_const_cmp1+0x1a/0x20 [ 64.586876][ C0] x86_64_start_reservations+0x29/0x2b [ 64.592390][ C0] x86_64_start_kernel+0x77/0x7b [ 64.597349][ C0] secondary_startup_64+0xa4/0xb0