[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [ 55.906490][ T26] audit: type=1800 audit(1567300508.225:25): pid=8507 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="cron" dev="sda1" ino=2414 res=0 [ 55.928055][ T26] audit: type=1800 audit(1567300508.225:26): pid=8507 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="mcstrans" dev="sda1" ino=2457 res=0 [ 55.949143][ T26] audit: type=1800 audit(1567300508.225:27): pid=8507 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 '10.128.0.27' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 67.287096][ C0] [ 67.289445][ C0] ======================================================== [ 67.296607][ C0] WARNING: possible irq lock inversion dependency detected [ 67.303783][ C0] 5.3.0-rc6-next-20190830 #75 Not tainted [ 67.309469][ C0] -------------------------------------------------------- [ 67.316648][ C0] swapper/0/0 just changed the state of lock: [ 67.322708][ C0] ffff888095047b58 (&(&ctx->ctx_lock)->rlock){..-.}, at: free_ioctx_users+0x2d/0x490 [ 67.332161][ C0] but this lock took another, SOFTIRQ-unsafe lock in the past: [ 67.339669][ C0] (&fiq->waitq){+.+.} [ 67.339675][ C0] [ 67.339675][ C0] [ 67.339675][ C0] and interrupts could create inverse lock ordering between them. [ 67.339675][ C0] [ 67.357998][ C0] [ 67.357998][ C0] other info that might help us debug this: [ 67.366028][ C0] Possible interrupt unsafe locking scenario: [ 67.366028][ C0] [ 67.374315][ C0] CPU0 CPU1 [ 67.379655][ C0] ---- ---- [ 67.384999][ C0] lock(&fiq->waitq); [ 67.389050][ C0] local_irq_disable(); [ 67.395789][ C0] lock(&(&ctx->ctx_lock)->rlock); [ 67.403486][ C0] lock(&fiq->waitq); [ 67.410177][ C0] [ 67.413613][ C0] lock(&(&ctx->ctx_lock)->rlock); [ 67.418951][ C0] [ 67.418951][ C0] *** DEADLOCK *** [ 67.418951][ C0] [ 67.427071][ C0] 2 locks held by swapper/0/0: [ 67.431807][ C0] #0: ffffffff88fa7e40 (rcu_callback){....}, at: rcu_core+0x60e/0x1560 [ 67.440115][ C0] #1: ffffffff88fa7e80 (rcu_read_lock_sched){....}, at: percpu_ref_switch_to_atomic_rcu+0x20e/0x570 [ 67.450963][ C0] [ 67.450963][ C0] the shortest dependencies between 2nd lock and 1st lock: [ 67.460315][ C0] -> (&fiq->waitq){+.+.} { [ 67.464791][ C0] HARDIRQ-ON-W at: [ 67.468851][ C0] lock_acquire+0x190/0x410 [ 67.475150][ C0] _raw_spin_lock+0x2f/0x40 [ 67.481445][ C0] flush_bg_queue+0x1f1/0x3b0 [ 67.487914][ C0] fuse_request_queue_background+0x2f8/0x5b0 [ 67.495684][ C0] fuse_request_send_background+0x58/0x110 [ 67.503281][ C0] cuse_channel_open+0x5c3/0x839 [ 67.510014][ C0] misc_open+0x395/0x4c0 [ 67.516054][ C0] chrdev_open+0x245/0x6b0 [ 67.522266][ C0] do_dentry_open+0x4df/0x1250 [ 67.528822][ C0] vfs_open+0xa0/0xd0 [ 67.534601][ C0] path_openat+0x10e9/0x46d0 [ 67.540984][ C0] do_filp_open+0x1a1/0x280 [ 67.547289][ C0] do_sys_open+0x3fe/0x5d0 [ 67.553499][ C0] __x64_sys_openat+0x9d/0x100 [ 67.560059][ C0] do_syscall_64+0xfa/0x760 [ 67.566359][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 67.574040][ C0] SOFTIRQ-ON-W at: [ 67.578083][ C0] lock_acquire+0x190/0x410 [ 67.584383][ C0] _raw_spin_lock+0x2f/0x40 [ 67.590676][ C0] flush_bg_queue+0x1f1/0x3b0 [ 67.597160][ C0] fuse_request_queue_background+0x2f8/0x5b0 [ 67.604932][ C0] fuse_request_send_background+0x58/0x110 [ 67.612534][ C0] cuse_channel_open+0x5c3/0x839 [ 67.619262][ C0] misc_open+0x395/0x4c0 [ 67.625297][ C0] chrdev_open+0x245/0x6b0 [ 67.631505][ C0] do_dentry_open+0x4df/0x1250 [ 67.638063][ C0] vfs_open+0xa0/0xd0 [ 67.643840][ C0] path_openat+0x10e9/0x46d0 [ 67.650244][ C0] do_filp_open+0x1a1/0x280 [ 67.656556][ C0] do_sys_open+0x3fe/0x5d0 [ 67.662771][ C0] __x64_sys_openat+0x9d/0x100 [ 67.669347][ C0] do_syscall_64+0xfa/0x760 [ 67.675644][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 67.683337][ C0] INITIAL USE at: [ 67.687293][ C0] lock_acquire+0x190/0x410 [ 67.693502][ C0] _raw_spin_lock+0x2f/0x40 [ 67.699713][ C0] flush_bg_queue+0x1f1/0x3b0 [ 67.706107][ C0] fuse_request_queue_background+0x2f8/0x5b0 [ 67.713793][ C0] fuse_request_send_background+0x58/0x110 [ 67.721307][ C0] cuse_channel_open+0x5c3/0x839 [ 67.727949][ C0] misc_open+0x395/0x4c0 [ 67.733897][ C0] chrdev_open+0x245/0x6b0 [ 67.740021][ C0] do_dentry_open+0x4df/0x1250 [ 67.746516][ C0] vfs_open+0xa0/0xd0 [ 67.752220][ C0] path_openat+0x10e9/0x46d0 [ 67.758622][ C0] do_filp_open+0x1a1/0x280 [ 67.764833][ C0] do_sys_open+0x3fe/0x5d0 [ 67.771072][ C0] __x64_sys_openat+0x9d/0x100 [ 67.777545][ C0] do_syscall_64+0xfa/0x760 [ 67.783849][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 67.791444][ C0] } [ 67.794012][ C0] ... key at: [] __key.44810+0x0/0x40 [ 67.801517][ C0] ... acquired at: [ 67.805395][ C0] _raw_spin_lock+0x2f/0x40 [ 67.810044][ C0] io_submit_one+0xefa/0x2ef0 [ 67.814863][ C0] __x64_sys_io_submit+0x1bd/0x570 [ 67.820118][ C0] do_syscall_64+0xfa/0x760 [ 67.824764][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 67.830794][ C0] [ 67.833104][ C0] -> (&(&ctx->ctx_lock)->rlock){..-.} { [ 67.838620][ C0] IN-SOFTIRQ-W at: [ 67.842580][ C0] lock_acquire+0x190/0x410 [ 67.848703][ C0] _raw_spin_lock_irq+0x60/0x80 [ 67.855173][ C0] free_ioctx_users+0x2d/0x490 [ 67.861586][ C0] percpu_ref_switch_to_atomic_rcu+0x4c0/0x570 [ 67.869379][ C0] rcu_core+0x581/0x1560 [ 67.875248][ C0] rcu_core_si+0x9/0x10 [ 67.881032][ C0] __do_softirq+0x262/0x98c [ 67.887156][ C0] irq_exit+0x19b/0x1e0 [ 67.892933][ C0] smp_apic_timer_interrupt+0x1a3/0x610 [ 67.900112][ C0] apic_timer_interrupt+0xf/0x20 [ 67.906688][ C0] native_safe_halt+0xe/0x10 [ 67.912904][ C0] default_enter_idle+0x71/0xf0 [ 67.919371][ C0] cpuidle_enter_state+0xef/0xfb0 [ 67.926012][ C0] cpuidle_enter+0x4f/0xa0 [ 67.932046][ C0] do_idle+0x45f/0x6e0 [ 67.937738][ C0] cpu_startup_entry+0x1b/0x20 [ 67.944120][ C0] rest_init+0x245/0x37b [ 67.949985][ C0] arch_call_rest_init+0xe/0x1b [ 67.956477][ C0] start_kernel+0x904/0x943 [ 67.962603][ C0] x86_64_start_reservations+0x29/0x2b [ 67.969682][ C0] x86_64_start_kernel+0x77/0x7b [ 67.976239][ C0] secondary_startup_64+0xa4/0xb0 [ 67.982876][ C0] INITIAL USE at: [ 67.986744][ C0] lock_acquire+0x190/0x410 [ 67.992781][ C0] _raw_spin_lock_irq+0x60/0x80 [ 67.999164][ C0] io_submit_one+0xeb5/0x2ef0 [ 68.005388][ C0] __x64_sys_io_submit+0x1bd/0x570 [ 68.012051][ C0] do_syscall_64+0xfa/0x760 [ 68.018109][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 68.025532][ C0] } [ 68.028033][ C0] ... key at: [] __key.54358+0x0/0x40 [ 68.035458][ C0] ... acquired at: [ 68.039252][ C0] mark_lock+0x517/0x1220 [ 68.043727][ C0] __lock_acquire+0x1e8e/0x4a00 [ 68.048722][ C0] lock_acquire+0x190/0x410 [ 68.053368][ C0] _raw_spin_lock_irq+0x60/0x80 [ 68.058360][ C0] free_ioctx_users+0x2d/0x490 [ 68.063269][ C0] percpu_ref_switch_to_atomic_rcu+0x4c0/0x570 [ 68.069562][ C0] rcu_core+0x581/0x1560 [ 68.073951][ C0] rcu_core_si+0x9/0x10 [ 68.078249][ C0] __do_softirq+0x262/0x98c [ 68.082895][ C0] irq_exit+0x19b/0x1e0 [ 68.087195][ C0] smp_apic_timer_interrupt+0x1a3/0x610 [ 68.092882][ C0] apic_timer_interrupt+0xf/0x20 [ 68.097962][ C0] native_safe_halt+0xe/0x10 [ 68.103840][ C0] default_enter_idle+0x71/0xf0 [ 68.108840][ C0] cpuidle_enter_state+0xef/0xfb0 [ 68.114009][ C0] cpuidle_enter+0x4f/0xa0 [ 68.118570][ C0] do_idle+0x45f/0x6e0 [ 68.122784][ C0] cpu_startup_entry+0x1b/0x20 [ 68.127691][ C0] rest_init+0x245/0x37b [ 68.132102][ C0] arch_call_rest_init+0xe/0x1b [ 68.137104][ C0] start_kernel+0x904/0x943 [ 68.141751][ C0] x86_64_start_reservations+0x29/0x2b [ 68.147352][ C0] x86_64_start_kernel+0x77/0x7b [ 68.152434][ C0] secondary_startup_64+0xa4/0xb0 [ 68.157597][ C0] [ 68.159895][ C0] [ 68.159895][ C0] stack backtrace: [ 68.165759][ C0] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.3.0-rc6-next-20190830 #75 [ 68.174051][ C0] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 68.184075][ C0] Call Trace: [ 68.187330][ C0] [ 68.190160][ C0] dump_stack+0x172/0x1f0 [ 68.194467][ C0] print_irq_inversion_bug.part.0+0x2e4/0x2f1 [ 68.200526][ C0] check_usage_forwards.cold+0x20/0x29 [ 68.205968][ C0] ? check_usage_backwards+0x330/0x330 [ 68.211402][ C0] ? save_trace+0x3e/0x8c0 [ 68.215810][ C0] mark_lock+0x517/0x1220 [ 68.220115][ C0] ? check_usage_backwards+0x330/0x330 [ 68.225551][ C0] __lock_acquire+0x1e8e/0x4a00 [ 68.230378][ C0] ? __kasan_check_read+0x11/0x20 [ 68.235373][ C0] ? mark_lock+0xc2/0x1220 [ 68.239761][ C0] ? mark_held_locks+0xf0/0xf0 [ 68.244497][ C0] lock_acquire+0x190/0x410 [ 68.248986][ C0] ? free_ioctx_users+0x2d/0x490 [ 68.253899][ C0] _raw_spin_lock_irq+0x60/0x80 [ 68.258808][ C0] ? free_ioctx_users+0x2d/0x490 [ 68.263731][ C0] free_ioctx_users+0x2d/0x490 [ 68.268483][ C0] ? rcu_dynticks_curr_cpu_in_eqs+0x54/0xb0 [ 68.274351][ C0] percpu_ref_switch_to_atomic_rcu+0x4c0/0x570 [ 68.280476][ C0] ? percpu_ref_exit+0xd0/0xd0 [ 68.285573][ C0] rcu_core+0x581/0x1560 [ 68.289798][ C0] ? __rcu_read_unlock+0x6b0/0x6b0 [ 68.294883][ C0] ? rcu_read_lock_sched_held+0x9c/0xd0 [ 68.300402][ C0] ? rcu_read_lock_any_held.part.0+0x50/0x50 [ 68.306370][ C0] ? run_rebalance_domains+0x227/0x2d0 [ 68.311803][ C0] rcu_core_si+0x9/0x10 [ 68.315933][ C0] __do_softirq+0x262/0x98c [ 68.320405][ C0] ? sched_clock_cpu+0x1b/0x1b0 [ 68.325231][ C0] irq_exit+0x19b/0x1e0 [ 68.329361][ C0] smp_apic_timer_interrupt+0x1a3/0x610 [ 68.334876][ C0] apic_timer_interrupt+0xf/0x20 [ 68.339781][ C0] [ 68.342695][ C0] RIP: 0010:native_safe_halt+0xe/0x10 [ 68.348043][ 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 [ 68.367619][ C0] RSP: 0018:ffffffff88e07c50 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff13 [ 68.375998][ C0] RAX: 1ffffffff11e5db7 RBX: 0000000000000000 RCX: 0000000000000000 [ 68.383958][ C0] RDX: dffffc0000000000 RSI: 0000000000000006 RDI: ffffffff88e7aa1c [ 68.391901][ C0] RBP: ffffffff88e07c80 R08: ffffffff88e7a180 R09: 0000000000000000 [ 68.399843][ C0] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000001 [ 68.407785][ C0] R13: 0000000000000000 R14: 0000000000000060 R15: 0000000000000001 [ 68.415752][ C0] ? default_idle+0x4e/0x360 [ 68.420316][ C0] default_enter_idle+0x71/0xf0 [ 68.425139][ C0] cpuidle_enter_state+0xef/0xfb0 [ 68.430135][ C0] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 68.436360][ C0] cpuidle_enter+0x4f/0xa0 [ 68.440748][ C0] do_idle+0x45f/0x6e0 [ 68.444792][ C0] ? arch_cpu_idle_exit+0x80/0x80 [ 68.449789][ C0] ? trace_hardirqs_on+0x30/0x240 [ 68.454783][ C0] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 68.461009][ C0] ? debug_smp_processor_id+0x3c/0x214 [ 68.466462][ C0] cpu_startup_entry+0x1b/0x20 [ 68.471197][ C0] rest_init+0x245/0x37b [ 68.475413][ C0] arch_call_rest_init+0xe/0x1b [ 68.480234][ C0] start_kernel+0x904/0x943 [ 68.484707][ C0] ? mem_encrypt_init+0xb/0xb [ 68.489359][ C0] ? __sanitizer