[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [ 55.889605][ T26] audit: type=1800 audit(1567345407.717:25): pid=8459 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="cron" dev="sda1" ino=2414 res=0 [ 55.911181][ T26] audit: type=1800 audit(1567345407.717:26): pid=8459 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="mcstrans" dev="sda1" ino=2457 res=0 [ 55.959605][ T26] audit: type=1800 audit(1567345407.717:27): pid=8459 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 '10.128.0.89' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 63.513015][ C1] [ 63.515389][ C1] ======================================================== [ 63.522552][ C1] WARNING: possible irq lock inversion dependency detected [ 63.529719][ C1] 5.3.0-rc6-next-20190830 #75 Not tainted [ 63.535419][ C1] -------------------------------------------------------- [ 63.542582][ C1] swapper/1/0 just changed the state of lock: [ 63.548620][ C1] ffff8880a79d1b58 (&(&ctx->ctx_lock)->rlock){..-.}, at: free_ioctx_users+0x2d/0x490 [ 63.558091][ C1] but this lock took another, SOFTIRQ-unsafe lock in the past: [ 63.565601][ C1] (&fiq->waitq){+.+.} [ 63.565607][ C1] [ 63.565607][ C1] [ 63.565607][ C1] and interrupts could create inverse lock ordering between them. [ 63.565607][ C1] [ 63.584193][ C1] [ 63.584193][ C1] other info that might help us debug this: [ 63.592235][ C1] Possible interrupt unsafe locking scenario: [ 63.592235][ C1] [ 63.600526][ C1] CPU0 CPU1 [ 63.605877][ C1] ---- ---- [ 63.611222][ C1] lock(&fiq->waitq); [ 63.615274][ C1] local_irq_disable(); [ 63.622273][ C1] lock(&(&ctx->ctx_lock)->rlock); [ 63.629973][ C1] lock(&fiq->waitq); [ 63.636534][ C1] [ 63.639961][ C1] lock(&(&ctx->ctx_lock)->rlock); [ 63.645331][ C1] [ 63.645331][ C1] *** DEADLOCK *** [ 63.645331][ C1] [ 63.653452][ C1] 2 locks held by swapper/1/0: [ 63.658181][ C1] #0: ffffffff88fa7e40 (rcu_callback){....}, at: rcu_core+0x60e/0x1560 [ 63.666491][ C1] #1: ffffffff88fa7e80 (rcu_read_lock_sched){....}, at: percpu_ref_switch_to_atomic_rcu+0x20e/0x570 [ 63.677330][ C1] [ 63.677330][ C1] the shortest dependencies between 2nd lock and 1st lock: [ 63.686673][ C1] -> (&fiq->waitq){+.+.} { [ 63.691149][ C1] HARDIRQ-ON-W at: [ 63.695297][ C1] lock_acquire+0x190/0x410 [ 63.701598][ C1] _raw_spin_lock+0x2f/0x40 [ 63.707915][ C1] flush_bg_queue+0x1f1/0x3b0 [ 63.714391][ C1] fuse_request_queue_background+0x2f8/0x5b0 [ 63.722166][ C1] fuse_request_send_background+0x58/0x110 [ 63.729781][ C1] cuse_channel_open+0x5c3/0x839 [ 63.736514][ C1] misc_open+0x395/0x4c0 [ 63.742562][ C1] chrdev_open+0x245/0x6b0 [ 63.748778][ C1] do_dentry_open+0x4df/0x1250 [ 63.755335][ C1] vfs_open+0xa0/0xd0 [ 63.761124][ C1] path_openat+0x10e9/0x46d0 [ 63.767511][ C1] do_filp_open+0x1a1/0x280 [ 63.773809][ C1] do_sys_open+0x3fe/0x5d0 [ 63.780018][ C1] __x64_sys_openat+0x9d/0x100 [ 63.786582][ C1] do_syscall_64+0xfa/0x760 [ 63.792882][ C1] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 63.800564][ C1] SOFTIRQ-ON-W at: [ 63.804714][ C1] lock_acquire+0x190/0x410 [ 63.811014][ C1] _raw_spin_lock+0x2f/0x40 [ 63.817315][ C1] flush_bg_queue+0x1f1/0x3b0 [ 63.823787][ C1] fuse_request_queue_background+0x2f8/0x5b0 [ 63.831559][ C1] fuse_request_send_background+0x58/0x110 [ 63.839173][ C1] cuse_channel_open+0x5c3/0x839 [ 63.845903][ C1] misc_open+0x395/0x4c0 [ 63.851943][ C1] chrdev_open+0x245/0x6b0 [ 63.858342][ C1] do_dentry_open+0x4df/0x1250 [ 63.864907][ C1] vfs_open+0xa0/0xd0 [ 63.870687][ C1] path_openat+0x10e9/0x46d0 [ 63.877071][ C1] do_filp_open+0x1a1/0x280 [ 63.883369][ C1] do_sys_open+0x3fe/0x5d0 [ 63.889586][ C1] __x64_sys_openat+0x9d/0x100 [ 63.896159][ C1] do_syscall_64+0xfa/0x760 [ 63.902465][ C1] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 63.910169][ C1] INITIAL USE at: [ 63.914133][ C1] lock_acquire+0x190/0x410 [ 63.920348][ C1] _raw_spin_lock+0x2f/0x40 [ 63.926558][ C1] flush_bg_queue+0x1f1/0x3b0 [ 63.932960][ C1] fuse_request_queue_background+0x2f8/0x5b0 [ 63.940648][ C1] fuse_request_send_background+0x58/0x110 [ 63.948167][ C1] cuse_channel_open+0x5c3/0x839 [ 63.954814][ C1] misc_open+0x395/0x4c0 [ 63.960783][ C1] chrdev_open+0x245/0x6b0 [ 63.966905][ C1] do_dentry_open+0x4df/0x1250 [ 63.973378][ C1] vfs_open+0xa0/0xd0 [ 63.979068][ C1] path_openat+0x10e9/0x46d0 [ 63.985378][ C1] do_filp_open+0x1a1/0x280 [ 63.991604][ C1] do_sys_open+0x3fe/0x5d0 [ 63.997727][ C1] __x64_sys_openat+0x9d/0x100 [ 64.004202][ C1] do_syscall_64+0xfa/0x760 [ 64.010427][ C1] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 64.018023][ C1] } [ 64.020606][ C1] ... key at: [] __key.44810+0x0/0x40 [ 64.028113][ C1] ... acquired at: [ 64.031983][ C1] _raw_spin_lock+0x2f/0x40 [ 64.036634][ C1] io_submit_one+0xefa/0x2ef0 [ 64.041455][ C1] __x64_sys_io_submit+0x1bd/0x570 [ 64.046722][ C1] do_syscall_64+0xfa/0x760 [ 64.051371][ C1] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 64.057400][ C1] [ 64.059698][ C1] -> (&(&ctx->ctx_lock)->rlock){..-.} { [ 64.065216][ C1] IN-SOFTIRQ-W at: [ 64.069176][ C1] lock_acquire+0x190/0x410 [ 64.075303][ C1] _raw_spin_lock_irq+0x60/0x80 [ 64.081796][ C1] free_ioctx_users+0x2d/0x490 [ 64.088196][ C1] percpu_ref_switch_to_atomic_rcu+0x4c0/0x570 [ 64.095981][ C1] rcu_core+0x581/0x1560 [ 64.101862][ C1] rcu_core_si+0x9/0x10 [ 64.107642][ C1] __do_softirq+0x262/0x98c [ 64.113768][ C1] irq_exit+0x19b/0x1e0 [ 64.119543][ C1] smp_apic_timer_interrupt+0x1a3/0x610 [ 64.126709][ C1] apic_timer_interrupt+0xf/0x20 [ 64.133289][ C1] native_safe_halt+0xe/0x10 [ 64.139507][ C1] default_enter_idle+0x71/0xf0 [ 64.145981][ C1] cpuidle_enter_state+0xef/0xfb0 [ 64.152623][ C1] cpuidle_enter+0x4f/0xa0 [ 64.158673][ C1] do_idle+0x45f/0x6e0 [ 64.164362][ C1] cpu_startup_entry+0x1b/0x20 [ 64.170781][ C1] start_secondary+0x2f4/0x410 [ 64.177169][ C1] secondary_startup_64+0xa4/0xb0 [ 64.183809][ C1] INITIAL USE at: [ 64.187685][ C1] lock_acquire+0x190/0x410 [ 64.193776][ C1] _raw_spin_lock_irq+0x60/0x80 [ 64.200159][ C1] io_submit_one+0xeb5/0x2ef0 [ 64.206387][ C1] __x64_sys_io_submit+0x1bd/0x570 [ 64.213036][ C1] do_syscall_64+0xfa/0x760 [ 64.219073][ C1] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 64.226507][ C1] } [ 64.228994][ C1] ... key at: [] __key.54358+0x0/0x40 [ 64.236419][ C1] ... acquired at: [ 64.240202][ C1] mark_lock+0x517/0x1220 [ 64.244690][ C1] __lock_acquire+0x1e8e/0x4a00 [ 64.249685][ C1] lock_acquire+0x190/0x410 [ 64.254334][ C1] _raw_spin_lock_irq+0x60/0x80 [ 64.259329][ C1] free_ioctx_users+0x2d/0x490 [ 64.264245][ C1] percpu_ref_switch_to_atomic_rcu+0x4c0/0x570 [ 64.270569][ C1] rcu_core+0x581/0x1560 [ 64.275051][ C1] rcu_core_si+0x9/0x10 [ 64.279362][ C1] __do_softirq+0x262/0x98c [ 64.284008][ C1] irq_exit+0x19b/0x1e0 [ 64.288329][ C1] smp_apic_timer_interrupt+0x1a3/0x610 [ 64.294022][ C1] apic_timer_interrupt+0xf/0x20 [ 64.299115][ C1] native_safe_halt+0xe/0x10 [ 64.303849][ C1] default_enter_idle+0x71/0xf0 [ 64.308844][ C1] cpuidle_enter_state+0xef/0xfb0 [ 64.314034][ C1] cpuidle_enter+0x4f/0xa0 [ 64.318599][ C1] do_idle+0x45f/0x6e0 [ 64.322813][ C1] cpu_startup_entry+0x1b/0x20 [ 64.327722][ C1] start_secondary+0x2f4/0x410 [ 64.332630][ C1] secondary_startup_64+0xa4/0xb0 [ 64.337797][ C1] [ 64.340119][ C1] [ 64.340119][ C1] stack backtrace: [ 64.345995][ C1] CPU: 1 PID: 0 Comm: swapper/1 Not tainted 5.3.0-rc6-next-20190830 #75 [ 64.354295][ C1] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 64.364322][ C1] Call Trace: [ 64.367576][ C1] [ 64.370411][ C1] dump_stack+0x172/0x1f0 [ 64.374719][ C1] print_irq_inversion_bug.part.0+0x2e4/0x2f1 [ 64.380763][ C1] check_usage_forwards.cold+0x20/0x29 [ 64.386211][ C1] ? check_usage_backwards+0x330/0x330 [ 64.391642][ C1] ? save_trace+0x3e/0x8c0 [ 64.396032][ C1] mark_lock+0x517/0x1220 [ 64.400434][ C1] ? check_usage_backwards+0x330/0x330 [ 64.405864][ C1] __lock_acquire+0x1e8e/0x4a00 [ 64.410686][ C1] ? __kasan_check_read+0x11/0x20 [ 64.415682][ C1] ? mark_lock+0xc2/0x1220 [ 64.420071][ C1] ? mark_held_locks+0xf0/0xf0 [ 64.424807][ C1] lock_acquire+0x190/0x410 [ 64.429281][ C1] ? free_ioctx_users+0x2d/0x490 [ 64.434194][ C1] _raw_spin_lock_irq+0x60/0x80 [ 64.439018][ C1] ? free_ioctx_users+0x2d/0x490 [ 64.443932][ C1] free_ioctx_users+0x2d/0x490 [ 64.448670][ C1] ? rcu_dynticks_curr_cpu_in_eqs+0x54/0xb0 [ 64.454537][ C1] percpu_ref_switch_to_atomic_rcu+0x4c0/0x570 [ 64.460661][ C1] ? percpu_ref_exit+0xd0/0xd0 [ 64.465394][ C1] rcu_core+0x581/0x1560 [ 64.469613][ C1] ? __rcu_read_unlock+0x6b0/0x6b0 [ 64.474703][ C1] ? rcu_read_lock_sched_held+0x9c/0xd0 [ 64.480220][ C1] ? rcu_read_lock_any_held.part.0+0x50/0x50 [ 64.486171][ C1] ? run_rebalance_domains+0x227/0x2d0 [ 64.491621][ C1] rcu_core_si+0x9/0x10 [ 64.495759][ C1] __do_softirq+0x262/0x98c [ 64.500235][ C1] ? sched_clock_cpu+0x1b/0x1b0 [ 64.505058][ C1] irq_exit+0x19b/0x1e0 [ 64.509198][ C1] smp_apic_timer_interrupt+0x1a3/0x610 [ 64.514714][ C1] apic_timer_interrupt+0xf/0x20 [ 64.519616][ C1] [ 64.522533][ C1] RIP: 0010:native_safe_halt+0xe/0x10 [ 64.527878][ 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 [ 64.547625][ C1] RSP: 0018:ffff8880a98dfcd0 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff13 [ 64.556009][ C1] RAX: 1ffffffff11e5db7 RBX: 0000000000000000 RCX: 0000000000000000 [ 64.563954][ C1] RDX: dffffc0000000000 RSI: 0000000000000006 RDI: ffff8880a98d0bdc [ 64.571896][ C1] RBP: ffff8880a98dfd00 R08: ffff8880a98d0340 R09: 0000000000000000 [ 64.579852][ C1] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000001 [ 64.587811][ C1] R13: 0000000000000000 R14: 0000000000000060 R15: 0000000000000001 [ 64.595765][ C1] ? default_idle+0x4e/0x360 [ 64.600331][ C1] default_enter_idle+0x71/0xf0 [ 64.605153][ C1] cpuidle_enter_state+0xef/0xfb0 [ 64.610150][ C1] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 64.616362][