[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [ 52.971654][ T26] audit: type=1800 audit(1568157985.403:25): pid=8461 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="cron" dev="sda1" ino=2414 res=0 [ 53.017416][ T26] audit: type=1800 audit(1568157985.403:26): pid=8461 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="mcstrans" dev="sda1" ino=2457 res=0 [ 53.043023][ T26] audit: type=1800 audit(1568157985.403:27): pid=8461 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 '10.128.0.173' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 63.538850][ C1] [ 63.541197][ C1] ======================================================== [ 63.548368][ C1] WARNING: possible irq lock inversion dependency detected [ 63.555573][ C1] 5.3.0-rc6-next-20190830 #75 Not tainted [ 63.561267][ C1] -------------------------------------------------------- [ 63.568433][ C1] swapper/1/0 just changed the state of lock: [ 63.574474][ C1] ffff888098e0fb58 (&(&ctx->ctx_lock)->rlock){..-.}, at: free_ioctx_users+0x2d/0x490 [ 63.583917][ C1] but this lock took another, SOFTIRQ-unsafe lock in the past: [ 63.591428][ C1] (&fiq->waitq){+.+.} [ 63.591433][ C1] [ 63.591433][ C1] [ 63.591433][ C1] and interrupts could create inverse lock ordering between them. [ 63.591433][ C1] [ 63.610017][ C1] [ 63.610017][ C1] other info that might help us debug this: [ 63.618055][ C1] Possible interrupt unsafe locking scenario: [ 63.618055][ C1] [ 63.626440][ C1] CPU0 CPU1 [ 63.631782][ C1] ---- ---- [ 63.637122][ C1] lock(&fiq->waitq); [ 63.641167][ C1] local_irq_disable(); [ 63.647946][ C1] lock(&(&ctx->ctx_lock)->rlock); [ 63.655632][ C1] lock(&fiq->waitq); [ 63.662195][ C1] [ 63.665627][ C1] lock(&(&ctx->ctx_lock)->rlock); [ 63.670970][ C1] [ 63.670970][ C1] *** DEADLOCK *** [ 63.670970][ C1] [ 63.679093][ C1] 2 locks held by swapper/1/0: [ 63.683827][ C1] #0: ffffffff88fa7e40 (rcu_callback){....}, at: rcu_core+0x60e/0x1560 [ 63.692135][ C1] #1: ffffffff88fa7e80 (rcu_read_lock_sched){....}, at: percpu_ref_switch_to_atomic_rcu+0x20e/0x570 [ 63.702961][ C1] [ 63.702961][ C1] the shortest dependencies between 2nd lock and 1st lock: [ 63.712313][ C1] -> (&fiq->waitq){+.+.} { [ 63.716838][ C1] HARDIRQ-ON-W at: [ 63.720890][ C1] lock_acquire+0x190/0x410 [ 63.727207][ C1] _raw_spin_lock+0x2f/0x40 [ 63.733513][ C1] flush_bg_queue+0x1f1/0x3b0 [ 63.739994][ C1] fuse_request_queue_background+0x2f8/0x5b0 [ 63.747776][ C1] fuse_request_send_background+0x58/0x110 [ 63.755420][ C1] cuse_channel_open+0x5c3/0x839 [ 63.762165][ C1] misc_open+0x395/0x4c0 [ 63.768211][ C1] chrdev_open+0x245/0x6b0 [ 63.774430][ C1] do_dentry_open+0x4df/0x1250 [ 63.780998][ C1] vfs_open+0xa0/0xd0 [ 63.786786][ C1] path_openat+0x10e9/0x46d0 [ 63.793178][ C1] do_filp_open+0x1a1/0x280 [ 63.799484][ C1] do_sys_open+0x3fe/0x5d0 [ 63.805697][ C1] __x64_sys_openat+0x9d/0x100 [ 63.812262][ C1] do_syscall_64+0xfa/0x760 [ 63.818567][ C1] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 63.826279][ C1] SOFTIRQ-ON-W at: [ 63.830355][ C1] lock_acquire+0x190/0x410 [ 63.836659][ C1] _raw_spin_lock+0x2f/0x40 [ 63.842959][ C1] flush_bg_queue+0x1f1/0x3b0 [ 63.849459][ C1] fuse_request_queue_background+0x2f8/0x5b0 [ 63.857234][ C1] fuse_request_send_background+0x58/0x110 [ 63.864876][ C1] cuse_channel_open+0x5c3/0x839 [ 63.871614][ C1] misc_open+0x395/0x4c0 [ 63.877674][ C1] chrdev_open+0x245/0x6b0 [ 63.883887][ C1] do_dentry_open+0x4df/0x1250 [ 63.890450][ C1] vfs_open+0xa0/0xd0 [ 63.896230][ C1] path_openat+0x10e9/0x46d0 [ 63.902633][ C1] do_filp_open+0x1a1/0x280 [ 63.908945][ C1] do_sys_open+0x3fe/0x5d0 [ 63.915165][ C1] __x64_sys_openat+0x9d/0x100 [ 63.921744][ C1] do_syscall_64+0xfa/0x760 [ 63.928056][ C1] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 63.935748][ C1] INITIAL USE at: [ 63.939775][ C1] lock_acquire+0x190/0x410 [ 63.945995][ C1] _raw_spin_lock+0x2f/0x40 [ 63.952216][ C1] flush_bg_queue+0x1f1/0x3b0 [ 63.958610][ C1] fuse_request_queue_background+0x2f8/0x5b0 [ 63.966347][ C1] fuse_request_send_background+0x58/0x110 [ 63.973889][ C1] cuse_channel_open+0x5c3/0x839 [ 63.980539][ C1] misc_open+0x395/0x4c0 [ 63.986495][ C1] chrdev_open+0x245/0x6b0 [ 63.992720][ C1] do_dentry_open+0x4df/0x1250 [ 63.999196][ C1] vfs_open+0xa0/0xd0 [ 64.004902][ C1] path_openat+0x10e9/0x46d0 [ 64.011206][ C1] do_filp_open+0x1a1/0x280 [ 64.017424][ C1] do_sys_open+0x3fe/0x5d0 [ 64.023552][ C1] __x64_sys_openat+0x9d/0x100 [ 64.030075][ C1] do_syscall_64+0xfa/0x760 [ 64.036289][ C1] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 64.043890][ C1] } [ 64.046510][ C1] ... key at: [] __key.44810+0x0/0x40 [ 64.054151][ C1] ... acquired at: [ 64.058026][ C1] _raw_spin_lock+0x2f/0x40 [ 64.062682][ C1] io_submit_one+0xefa/0x2ef0 [ 64.067532][ C1] __x64_sys_io_submit+0x1bd/0x570 [ 64.072792][ C1] do_syscall_64+0xfa/0x760 [ 64.077445][ C1] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 64.083480][ C1] [ 64.085804][ C1] -> (&(&ctx->ctx_lock)->rlock){..-.} { [ 64.091328][ C1] IN-SOFTIRQ-W at: [ 64.095288][ C1] lock_acquire+0x190/0x410 [ 64.101439][ C1] _raw_spin_lock_irq+0x60/0x80 [ 64.107914][ C1] free_ioctx_users+0x2d/0x490 [ 64.114311][ C1] percpu_ref_switch_to_atomic_rcu+0x4c0/0x570 [ 64.122088][ C1] rcu_core+0x581/0x1560 [ 64.127953][ C1] rcu_core_si+0x9/0x10 [ 64.133735][ C1] __do_softirq+0x262/0x98c [ 64.139875][ C1] irq_exit+0x19b/0x1e0 [ 64.145656][ C1] smp_apic_timer_interrupt+0x1a3/0x610 [ 64.152851][ C1] apic_timer_interrupt+0xf/0x20 [ 64.159533][ C1] native_safe_halt+0xe/0x10 [ 64.165760][ C1] default_enter_idle+0x71/0xf0 [ 64.172249][ C1] cpuidle_enter_state+0xef/0xfb0 [ 64.178902][ C1] cpuidle_enter+0x4f/0xa0 [ 64.184948][ C1] do_idle+0x45f/0x6e0 [ 64.190643][ C1] cpu_startup_entry+0x1b/0x20 [ 64.197034][ C1] start_secondary+0x2f4/0x410 [ 64.203483][ C1] secondary_startup_64+0xa4/0xb0 [ 64.210172][ C1] INITIAL USE at: [ 64.214050][ C1] lock_acquire+0x190/0x410 [ 64.220096][ C1] _raw_spin_lock_irq+0x60/0x80 [ 64.226486][ C1] io_submit_one+0xeb5/0x2ef0 [ 64.232702][ C1] __x64_sys_io_submit+0x1bd/0x570 [ 64.239353][ C1] do_syscall_64+0xfa/0x760 [ 64.245440][ C1] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 64.252980][ C1] } [ 64.255468][ C1] ... key at: [] __key.54358+0x0/0x40 [ 64.262895][ C1] ... acquired at: [ 64.266681][ C1] mark_lock+0x517/0x1220 [ 64.271160][ C1] __lock_acquire+0x1e8e/0x4a00 [ 64.276279][ C1] lock_acquire+0x190/0x410 [ 64.280935][ C1] _raw_spin_lock_irq+0x60/0x80 [ 64.285960][ C1] free_ioctx_users+0x2d/0x490 [ 64.290876][ C1] percpu_ref_switch_to_atomic_rcu+0x4c0/0x570 [ 64.297179][ C1] rcu_core+0x581/0x1560 [ 64.301570][ C1] rcu_core_si+0x9/0x10 [ 64.305876][ C1] __do_softirq+0x262/0x98c [ 64.310526][ C1] irq_exit+0x19b/0x1e0 [ 64.314837][ C1] smp_apic_timer_interrupt+0x1a3/0x610 [ 64.320531][ C1] apic_timer_interrupt+0xf/0x20 [ 64.325618][ C1] native_safe_halt+0xe/0x10 [ 64.330361][ C1] default_enter_idle+0x71/0xf0 [ 64.335361][ C1] cpuidle_enter_state+0xef/0xfb0 [ 64.340534][ C1] cpuidle_enter+0x4f/0xa0 [ 64.345100][ C1] do_idle+0x45f/0x6e0 [ 64.349317][ C1] cpu_startup_entry+0x1b/0x20 [ 64.354230][ C1] start_secondary+0x2f4/0x410 [ 64.359143][ C1] secondary_startup_64+0xa4/0xb0 [ 64.364312][ C1] [ 64.366615][ C1] [ 64.366615][ C1] stack backtrace: [ 64.372485][ C1] CPU: 1 PID: 0 Comm: swapper/1 Not tainted 5.3.0-rc6-next-20190830 #75 [ 64.380778][ C1] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 64.390806][ C1] Call Trace: [ 64.394067][ C1] [ 64.396903][ C1] dump_stack+0x172/0x1f0 [ 64.401243][ C1] print_irq_inversion_bug.part.0+0x2e4/0x2f1 [ 64.407319][ C1] check_usage_forwards.cold+0x20/0x29 [ 64.412778][ C1] ? check_usage_backwards+0x330/0x330 [ 64.418240][ C1] ? save_trace+0x3e/0x8c0 [ 64.422636][ C1] mark_lock+0x517/0x1220 [ 64.426943][ C1] ? check_usage_backwards+0x330/0x330 [ 64.432379][ C1] __lock_acquire+0x1e8e/0x4a00 [ 64.437210][ C1] ? __kasan_check_read+0x11/0x20 [ 64.442251][ C1] ? mark_lock+0xc2/0x1220 [ 64.446647][ C1] ? mark_held_locks+0xf0/0xf0 [ 64.451389][ C1] lock_acquire+0x190/0x410 [ 64.455897][ C1] ? free_ioctx_users+0x2d/0x490 [ 64.460815][ C1] _raw_spin_lock_irq+0x60/0x80 [ 64.465642][ C1] ? free_ioctx_users+0x2d/0x490 [ 64.470555][ C1] free_ioctx_users+0x2d/0x490 [ 64.475297][ C1] ? rcu_dynticks_curr_cpu_in_eqs+0x54/0xb0 [ 64.481168][ C1] percpu_ref_switch_to_atomic_rcu+0x4c0/0x570 [ 64.487298][ C1] ? percpu_ref_exit+0xd0/0xd0 [ 64.492035][ C1] rcu_core+0x581/0x1560 [ 64.496254][ C1] ? __rcu_read_unlock+0x6b0/0x6b0 [ 64.501353][ C1] ? rcu_read_lock_sched_held+0x9c/0xd0 [ 64.506875][ C1] ? rcu_read_lock_any_held.part.0+0x50/0x50 [ 64.512832][ C1] ? run_rebalance_domains+0x227/0x2d0 [ 64.518289][ C1] rcu_core_si+0x9/0x10 [ 64.522528][ C1] __do_softirq+0x262/0x98c [ 64.527006][ C1] ? sched_clock_cpu+0x1b/0x1b0 [ 64.531834][ C1] irq_exit+0x19b/0x1e0 [ 64.535966][ C1] smp_apic_timer_interrupt+0x1a3/0x610 [ 64.541487][ C1] apic_timer_interrupt+0xf/0x20 [ 64.546400][ C1] [ 64.549318][ C1] RIP: 0010:native_safe_halt+0xe/0x10 [ 64.554669][ 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 [ 64.574335][ C1] RSP: 0018:ffff8880a98dfcd0 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff13 [ 64.582722][ C1] RAX: 1ffffffff11e5db7 RBX: 0000000000000000 RCX: 0000000000000000 [ 64.590670][ C1] RDX: dffffc0000000000 RSI: 0000000000000006 RDI: ffff8880a98d0bdc [ 64.598620][ C1] RBP: ffff8880a98dfd00 R08: ffff8880a98d0340 R09: 0000000000000000 [ 64.606663][ C1] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000001 [ 64.614610][ C1] R13: 0000000000000000 R14: 0000000000000060 R15: 0000000000000001 [ 64.622572][ C1] ? default_idle+0x4e/0x360 [ 64.627227][ C1] default_enter_idle+0x71/0xf0 [ 64.632057][ C1] cpuidle_enter_state+0xef/0xfb0 [ 64.637059][ C1] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 6