[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [ 55.509309][ T26] audit: type=1800 audit(1567375204.617:25): pid=8577 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="cron" dev="sda1" ino=2414 res=0 [ 55.548326][ T26] audit: type=1800 audit(1567375204.617:26): pid=8577 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="mcstrans" dev="sda1" ino=2457 res=0 [ 55.589002][ T26] audit: type=1800 audit(1567375204.617:27): pid=8577 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 '10.128.0.102' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 66.268358][ C1] [ 66.270845][ C1] ======================================================== [ 66.278015][ C1] WARNING: possible irq lock inversion dependency detected [ 66.285189][ C1] 5.3.0-rc6-next-20190830 #75 Not tainted [ 66.290897][ C1] -------------------------------------------------------- [ 66.298263][ C1] swapper/1/0 just changed the state of lock: [ 66.304358][ C1] ffff88809105fb58 (&(&ctx->ctx_lock)->rlock){..-.}, at: free_ioctx_users+0x2d/0x490 [ 66.313928][ C1] but this lock took another, SOFTIRQ-unsafe lock in the past: [ 66.321443][ C1] (&fiq->waitq){+.+.} [ 66.321451][ C1] [ 66.321451][ C1] [ 66.321451][ C1] and interrupts could create inverse lock ordering between them. [ 66.321451][ C1] [ 66.339785][ C1] [ 66.339785][ C1] other info that might help us debug this: [ 66.347842][ C1] Possible interrupt unsafe locking scenario: [ 66.347842][ C1] [ 66.356141][ C1] CPU0 CPU1 [ 66.361483][ C1] ---- ---- [ 66.366828][ C1] lock(&fiq->waitq); [ 66.370879][ C1] local_irq_disable(); [ 66.377619][ C1] lock(&(&ctx->ctx_lock)->rlock); [ 66.385309][ C1] lock(&fiq->waitq); [ 66.391879][ C1] [ 66.395398][ C1] lock(&(&ctx->ctx_lock)->rlock); [ 66.400739][ C1] [ 66.400739][ C1] *** DEADLOCK *** [ 66.400739][ C1] [ 66.408863][ C1] 2 locks held by swapper/1/0: [ 66.413599][ C1] #0: ffffffff88fa7e40 (rcu_callback){....}, at: rcu_core+0x60e/0x1560 [ 66.421938][ C1] #1: ffffffff88fa7e80 (rcu_read_lock_sched){....}, at: percpu_ref_switch_to_atomic_rcu+0x20e/0x570 [ 66.432797][ C1] [ 66.432797][ C1] the shortest dependencies between 2nd lock and 1st lock: [ 66.442155][ C1] -> (&fiq->waitq){+.+.} { [ 66.446666][ C1] HARDIRQ-ON-W at: [ 66.450728][ C1] lock_acquire+0x190/0x410 [ 66.457050][ C1] _raw_spin_lock+0x2f/0x40 [ 66.463356][ C1] flush_bg_queue+0x1f1/0x3b0 [ 66.469840][ C1] fuse_request_queue_background+0x2f8/0x5b0 [ 66.477617][ C1] fuse_request_send_background+0x58/0x110 [ 66.485224][ C1] cuse_channel_open+0x5c3/0x839 [ 66.491982][ C1] misc_open+0x395/0x4c0 [ 66.498194][ C1] chrdev_open+0x245/0x6b0 [ 66.504424][ C1] do_dentry_open+0x4df/0x1250 [ 66.511186][ C1] vfs_open+0xa0/0xd0 [ 66.516994][ C1] path_openat+0x10e9/0x46d0 [ 66.523416][ C1] do_filp_open+0x1a1/0x280 [ 66.529748][ C1] do_sys_open+0x3fe/0x5d0 [ 66.535973][ C1] __x64_sys_openat+0x9d/0x100 [ 66.542574][ C1] do_syscall_64+0xfa/0x760 [ 66.548907][ C1] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 66.556608][ C1] SOFTIRQ-ON-W at: [ 66.560668][ C1] lock_acquire+0x190/0x410 [ 66.566993][ C1] _raw_spin_lock+0x2f/0x40 [ 66.573304][ C1] flush_bg_queue+0x1f1/0x3b0 [ 66.579789][ C1] fuse_request_queue_background+0x2f8/0x5b0 [ 66.587654][ C1] fuse_request_send_background+0x58/0x110 [ 66.595274][ C1] cuse_channel_open+0x5c3/0x839 [ 66.602107][ C1] misc_open+0x395/0x4c0 [ 66.608159][ C1] chrdev_open+0x245/0x6b0 [ 66.614507][ C1] do_dentry_open+0x4df/0x1250 [ 66.621082][ C1] vfs_open+0xa0/0xd0 [ 66.626886][ C1] path_openat+0x10e9/0x46d0 [ 66.633288][ C1] do_filp_open+0x1a1/0x280 [ 66.639596][ C1] do_sys_open+0x3fe/0x5d0 [ 66.645812][ C1] __x64_sys_openat+0x9d/0x100 [ 66.652471][ C1] do_syscall_64+0xfa/0x760 [ 66.658782][ C1] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 66.666489][ C1] INITIAL USE at: [ 66.670467][ C1] lock_acquire+0x190/0x410 [ 66.676686][ C1] _raw_spin_lock+0x2f/0x40 [ 66.682904][ C1] flush_bg_queue+0x1f1/0x3b0 [ 66.689303][ C1] fuse_request_queue_background+0x2f8/0x5b0 [ 66.696993][ C1] fuse_request_send_background+0x58/0x110 [ 66.704601][ C1] cuse_channel_open+0x5c3/0x839 [ 66.711253][ C1] misc_open+0x395/0x4c0 [ 66.717207][ C1] chrdev_open+0x245/0x6b0 [ 66.723340][ C1] do_dentry_open+0x4df/0x1250 [ 66.729818][ C1] vfs_open+0xa0/0xd0 [ 66.735703][ C1] path_openat+0x10e9/0x46d0 [ 66.742006][ C1] do_filp_open+0x1a1/0x280 [ 66.748237][ C1] do_sys_open+0x3fe/0x5d0 [ 66.754368][ C1] __x64_sys_openat+0x9d/0x100 [ 66.760859][ C1] do_syscall_64+0xfa/0x760 [ 66.767079][ C1] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 66.774683][ C1] } [ 66.777266][ C1] ... key at: [] __key.44810+0x0/0x40 [ 66.784890][ C1] ... acquired at: [ 66.788780][ C1] _raw_spin_lock+0x2f/0x40 [ 66.793449][ C1] io_submit_one+0xefa/0x2ef0 [ 66.798286][ C1] __x64_sys_io_submit+0x1bd/0x570 [ 66.803563][ C1] do_syscall_64+0xfa/0x760 [ 66.808226][ C1] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 66.814266][ C1] [ 66.816656][ C1] -> (&(&ctx->ctx_lock)->rlock){..-.} { [ 66.822283][ C1] IN-SOFTIRQ-W at: [ 66.826279][ C1] lock_acquire+0x190/0x410 [ 66.832422][ C1] _raw_spin_lock_irq+0x60/0x80 [ 66.838910][ C1] free_ioctx_users+0x2d/0x490 [ 66.845311][ C1] percpu_ref_switch_to_atomic_rcu+0x4c0/0x570 [ 66.853099][ C1] rcu_core+0x581/0x1560 [ 66.859083][ C1] rcu_core_si+0x9/0x10 [ 66.864873][ C1] __do_softirq+0x262/0x98c [ 66.871003][ C1] irq_exit+0x19b/0x1e0 [ 66.876876][ C1] smp_apic_timer_interrupt+0x1a3/0x610 [ 66.884160][ C1] apic_timer_interrupt+0xf/0x20 [ 66.890733][ C1] native_safe_halt+0xe/0x10 [ 66.897063][ C1] default_enter_idle+0x71/0xf0 [ 66.903891][ C1] cpuidle_enter_state+0xef/0xfb0 [ 66.910564][ C1] cpuidle_enter+0x4f/0xa0 [ 66.916637][ C1] do_idle+0x45f/0x6e0 [ 66.922366][ C1] cpu_startup_entry+0x1b/0x20 [ 66.928766][ C1] start_secondary+0x2f4/0x410 [ 66.935185][ C1] secondary_startup_64+0xa4/0xb0 [ 66.941833][ C1] INITIAL USE at: [ 66.945720][ C1] lock_acquire+0x190/0x410 [ 66.951880][ C1] _raw_spin_lock_irq+0x60/0x80 [ 66.958282][ C1] io_submit_one+0xeb5/0x2ef0 [ 66.964499][ C1] __x64_sys_io_submit+0x1bd/0x570 [ 66.971151][ C1] do_syscall_64+0xfa/0x760 [ 66.977216][ C1] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 66.984642][ C1] } [ 66.987135][ C1] ... key at: [] __key.54358+0x0/0x40 [ 66.994592][ C1] ... acquired at: [ 66.998391][ C1] mark_lock+0x517/0x1220 [ 67.002870][ C1] __lock_acquire+0x1e8e/0x4a00 [ 67.007975][ C1] lock_acquire+0x190/0x410 [ 67.012649][ C1] _raw_spin_lock_irq+0x60/0x80 [ 67.017649][ C1] free_ioctx_users+0x2d/0x490 [ 67.022563][ C1] percpu_ref_switch_to_atomic_rcu+0x4c0/0x570 [ 67.028889][ C1] rcu_core+0x581/0x1560 [ 67.033287][ C1] rcu_core_si+0x9/0x10 [ 67.037594][ C1] __do_softirq+0x262/0x98c [ 67.042254][ C1] irq_exit+0x19b/0x1e0 [ 67.046560][ C1] smp_apic_timer_interrupt+0x1a3/0x610 [ 67.052255][ C1] apic_timer_interrupt+0xf/0x20 [ 67.057342][ C1] native_safe_halt+0xe/0x10 [ 67.062187][ C1] default_enter_idle+0x71/0xf0 [ 67.067303][ C1] cpuidle_enter_state+0xef/0xfb0 [ 67.072506][ C1] cpuidle_enter+0x4f/0xa0 [ 67.077081][ C1] do_idle+0x45f/0x6e0 [ 67.081306][ C1] cpu_startup_entry+0x1b/0x20 [ 67.086256][ C1] start_secondary+0x2f4/0x410 [ 67.091169][ C1] secondary_startup_64+0xa4/0xb0 [ 67.096450][ C1] [ 67.098787][ C1] [ 67.098787][ C1] stack backtrace: [ 67.104666][ C1] CPU: 1 PID: 0 Comm: swapper/1 Not tainted 5.3.0-rc6-next-20190830 #75 [ 67.112965][ C1] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 67.123009][ C1] Call Trace: [ 67.130935][ C1] [ 67.134094][ C1] dump_stack+0x172/0x1f0 [ 67.142065][ C1] print_irq_inversion_bug.part.0+0x2e4/0x2f1 [ 67.156428][ C1] check_usage_forwards.cold+0x20/0x29 [ 67.171741][ C1] ? check_usage_backwards+0x330/0x330 [ 67.177188][ C1] ? save_trace+0x3e/0x8c0 [ 67.181609][ C1] mark_lock+0x517/0x1220 [ 67.185988][ C1] ? check_usage_backwards+0x330/0x330 [ 67.191562][ C1] __lock_acquire+0x1e8e/0x4a00 [ 67.196400][ C1] ? __kasan_check_read+0x11/0x20 [ 67.201426][ C1] ? mark_lock+0xc2/0x1220 [ 67.205841][ C1] ? mark_held_locks+0xf0/0xf0 [ 67.210623][ C1] lock_acquire+0x190/0x410 [ 67.215134][ C1] ? free_ioctx_users+0x2d/0x490 [ 67.220090][ C1] _raw_spin_lock_irq+0x60/0x80 [ 67.225057][ C1] ? free_ioctx_users+0x2d/0x490 [ 67.230082][ C1] free_ioctx_users+0x2d/0x490 [ 67.234946][ C1] ? rcu_dynticks_curr_cpu_in_eqs+0x54/0xb0 [ 67.240821][ C1] percpu_ref_switch_to_atomic_rcu+0x4c0/0x570 [ 67.247080][ C1] ? percpu_ref_exit+0xd0/0xd0 [ 67.251919][ C1] rcu_core+0x581/0x1560 [ 67.256155][ C1] ? __rcu_read_unlock+0x6b0/0x6b0 [ 67.261256][ C1] ? rcu_read_lock_sched_held+0x9c/0xd0 [ 67.266777][ C1] ? rcu_read_lock_any_held.part.0+0x50/0x50 [ 67.272852][ C1] ? run_rebalance_domains+0x227/0x2d0 [ 67.278291][ C1] rcu_core_si+0x9/0x10 [ 67.282618][ C1] __do_softirq+0x262/0x98c [ 67.287101][ C1] ? sched_clock_cpu+0x1b/0x1b0 [ 67.291940][ C1] irq_exit+0x19b/0x1e0 [ 67.296075][ C1] smp_apic_timer_interrupt+0x1a3/0x610 [ 67.301599][ C1] apic_timer_interrupt+0xf/0x20 [ 67.306505][ C1] [ 67.309429][ C1] RIP: 0010:native_safe_halt+0xe/0x10 [ 67.314781][ 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 [ 67.334365][ C1] RSP: 0018:ffff8880a98dfcd0 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff13 [ 67.342758][ C1] RAX: 1ffffffff11e5db7 RBX: 0000000000000000 RCX: 0000000000000000 [ 67.350732][ C1] RDX: dffffc0000000000 RSI: 0000000000000006 RDI: ffff8880a98d0bdc [ 67.358683][ C1] RBP: ffff8880a98dfd00 R08: ffff8880a98d0340 R09: 0000000000000000 [ 67.366632][ C1] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000001 [ 67.374578][ C1] R13: 0000000000000000 R14: 0000000000000060 R15: 0000000000000001 [ 67.382576][ C1] ? default_idle+0x4e/0x360 [ 67.387240][ C1] default_enter_idle+0x71/0xf0 [ 67.392067][ C1] cpuidle_enter_state+0xef/0xfb0 [ 67.397076][ C1] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 67.403317][ C1] cpuidle_enter+0x4f/0xa0 [ 67.407746][ C1] do_idle+0x45f/0x6e0 [ 67.411798][ C1] ? arch_cpu_idle_exit+0x80/0x80 [ 67.416811][ C1] ? do_idle+0x387/0x6e0 [ 67.421055][ C1] cpu_s