[ OK ] Started Getty on tty5. [ OK ] Reached target Login Prompts. [ OK ] Reached target Multi-User System. [ OK ] Reached target Graphical Interface. Starting Update UTMP about System Runlevel Changes... Debian GNU/Linux 9 syzkaller ttyS0 Warning: Permanently added '10.128.0.113' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 61.602499][ C0] [ 61.604973][ C0] ======================================================== [ 61.612137][ C0] WARNING: possible irq lock inversion dependency detected [ 61.619311][ C0] 5.6.0-syzkaller #0 Not tainted [ 61.624229][ C0] -------------------------------------------------------- [ 61.631480][ C0] swapper/0/0 just changed the state of lock: [ 61.637540][ C0] ffff88809757bcd8 (&ctx->ctx_lock){..-.}-{2:2}, at: free_ioctx_users+0x2b/0x450 [ 61.646642][ C0] but this lock took another, SOFTIRQ-unsafe lock in the past: [ 61.654230][ C0] (&pid->wait_pidfd){+.+.}-{2:2} [ 61.654240][ C0] [ 61.654240][ C0] [ 61.654240][ C0] and interrupts could create inverse lock ordering between them. [ 61.654240][ C0] [ 61.673802][ C0] [ 61.673802][ C0] other info that might help us debug this: [ 61.681850][ C0] Possible interrupt unsafe locking scenario: [ 61.681850][ C0] [ 61.690144][ C0] CPU0 CPU1 [ 61.695682][ C0] ---- ---- [ 61.701247][ C0] lock(&pid->wait_pidfd); [ 61.706042][ C0] local_irq_disable(); [ 61.713033][ C0] lock(&ctx->ctx_lock); [ 61.719857][ C0] lock(&pid->wait_pidfd); [ 61.726876][ C0] [ 61.730325][ C0] lock(&ctx->ctx_lock); [ 61.734811][ C0] [ 61.734811][ C0] *** DEADLOCK *** [ 61.734811][ C0] [ 61.742958][ C0] 2 locks held by swapper/0/0: [ 61.747716][ C0] #0: ffffffff899bbaa0 (rcu_callback){....}-{0:0}, at: rcu_core+0x520/0x1370 [ 61.757253][ C0] #1: ffffffff899bbbc0 (rcu_read_lock){....}-{1:2}, at: percpu_ref_switch_to_atomic_rcu+0x209/0x540 [ 61.768101][ C0] [ 61.768101][ C0] the shortest dependencies between 2nd lock and 1st lock: [ 61.777472][ C0] -> (&pid->wait_pidfd){+.+.}-{2:2} { [ 61.782910][ C0] HARDIRQ-ON-W at: [ 61.786965][ C0] lock_acquire+0x1f2/0x8f0 [ 61.793946][ C0] _raw_spin_lock+0x2a/0x40 [ 61.800263][ C0] proc_pid_make_inode+0x1f9/0x3c0 [ 61.807176][ C0] proc_pid_instantiate+0x51/0x150 [ 61.814116][ C0] proc_pid_lookup+0x1da/0x340 [ 61.820690][ C0] proc_root_lookup+0x20/0x60 [ 61.827182][ C0] __lookup_slow+0x256/0x490 [ 61.833585][ C0] walk_component+0x418/0x6a0 [ 61.840183][ C0] link_path_walk.part.0+0x4f1/0xb50 [ 61.847275][ C0] path_openat+0x25a/0x27d0 [ 61.853596][ C0] do_filp_open+0x192/0x260 [ 61.859900][ C0] do_sys_openat2+0x585/0x7d0 [ 61.866373][ C0] do_sys_open+0xc3/0x140 [ 61.872514][ C0] do_syscall_64+0xf6/0x7d0 [ 61.878856][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xb3 [ 61.886565][ C0] SOFTIRQ-ON-W at: [ 61.890612][ C0] lock_acquire+0x1f2/0x8f0 [ 61.896929][ C0] _raw_spin_lock+0x2a/0x40 [ 61.903304][ C0] proc_pid_make_inode+0x1f9/0x3c0 [ 61.910242][ C0] proc_pid_instantiate+0x51/0x150 [ 61.917178][ C0] proc_pid_lookup+0x1da/0x340 [ 61.924961][ C0] proc_root_lookup+0x20/0x60 [ 61.931535][ C0] __lookup_slow+0x256/0x490 [ 61.937943][ C0] walk_component+0x418/0x6a0 [ 61.944423][ C0] link_path_walk.part.0+0x4f1/0xb50 [ 61.951557][ C0] path_openat+0x25a/0x27d0 [ 61.957859][ C0] do_filp_open+0x192/0x260 [ 61.964463][ C0] do_sys_openat2+0x585/0x7d0 [ 61.971043][ C0] do_sys_open+0xc3/0x140 [ 61.977221][ C0] do_syscall_64+0xf6/0x7d0 [ 61.984435][ C0] entry_SYSCALL_64_after_hwframe+0x49/0xb3 [ 61.992138][ C0] INITIAL USE at: [ 61.996116][ C0] lock_acquire+0x1f2/0x8f0 [ 62.002644][ C0] _raw_spin_lock_irqsave+0x8c/0xbf [ 62.009600][ C0] __wake_up_common_lock+0xb4/0x130 [ 62.017052][ C0] do_notify_parent+0x19e/0xe60 [ 62.023627][ C0] do_exit+0x238f/0x2dd0 [ 62.029588][ C0] call_usermodehelper_exec_async+0x507/0x710 [ 62.037642][ C0] ret_from_fork+0x24/0x30 [ 62.043774][ C0] } [ 62.046361][ C0] ... key at: [] __key.53827+0x0/0x40 [ 62.054110][ C0] ... acquired at: [ 62.057995][ C0] _raw_spin_lock+0x2a/0x40 [ 62.062819][ C0] io_submit_one+0xc1b/0x2ec0 [ 62.067960][ C0] __ia32_compat_sys_io_submit+0x1bf/0x530 [ 62.073935][ C0] do_fast_syscall_32+0x270/0xe90 [ 62.079230][ C0] entry_SYSENTER_compat+0x70/0x7f [ 62.084611][ C0] [ 62.087908][ C0] -> (&ctx->ctx_lock){..-.}-{2:2} { [ 62.093103][ C0] IN-SOFTIRQ-W at: [ 62.097075][ C0] lock_acquire+0x1f2/0x8f0 [ 62.103225][ C0] _raw_spin_lock_irq+0x5b/0x80 [ 62.109715][ C0] free_ioctx_users+0x2b/0x450 [ 62.116825][ C0] percpu_ref_switch_to_atomic_rcu+0x494/0x540 [ 62.125143][ C0] rcu_core+0x59f/0x1370 [ 62.131030][ C0] __do_softirq+0x26c/0x9f7 [ 62.137159][ C0] irq_exit+0x192/0x1d0 [ 62.143461][ C0] smp_apic_timer_interrupt+0x19e/0x600 [ 62.150854][ C0] apic_timer_interrupt+0xf/0x20 [ 62.158951][ C0] native_safe_halt+0xe/0x10 [ 62.165186][ C0] default_idle+0x49/0x350 [ 62.171333][ C0] do_idle+0x393/0x690 [ 62.177049][ C0] cpu_startup_entry+0x14/0x20 [ 62.183722][ C0] start_kernel+0x867/0x8a1 [ 62.190164][ C0] secondary_startup_64+0xa4/0xb0 [ 62.196983][ C0] INITIAL USE at: [ 62.200866][ C0] lock_acquire+0x1f2/0x8f0 [ 62.207011][ C0] _raw_spin_lock_irq+0x5b/0x80 [ 62.213550][ C0] io_submit_one+0xbd6/0x2ec0 [ 62.219906][ C0] __ia32_compat_sys_io_submit+0x1bf/0x530 [ 62.227260][ C0] do_fast_syscall_32+0x270/0xe90 [ 62.233844][ C0] entry_SYSENTER_compat+0x70/0x7f [ 62.242167][ C0] } [ 62.244779][ C0] ... key at: [] __key.55303+0x0/0x40 [ 62.252363][ C0] ... acquired at: [ 62.256171][ C0] mark_lock+0x624/0xf10 [ 62.260613][ C0] __lock_acquire+0x1d28/0x4e00 [ 62.266190][ C0] lock_acquire+0x1f2/0x8f0 [ 62.270849][ C0] _raw_spin_lock_irq+0x5b/0x80 [ 62.275869][ C0] free_ioctx_users+0x2b/0x450 [ 62.280796][ C0] percpu_ref_switch_to_atomic_rcu+0x494/0x540 [ 62.287098][ C0] rcu_core+0x59f/0x1370 [ 62.291502][ C0] __do_softirq+0x26c/0x9f7 [ 62.296154][ C0] irq_exit+0x192/0x1d0 [ 62.301347][ C0] smp_apic_timer_interrupt+0x19e/0x600 [ 62.307057][ C0] apic_timer_interrupt+0xf/0x20 [ 62.312157][ C0] native_safe_halt+0xe/0x10 [ 62.317970][ C0] default_idle+0x49/0x350 [ 62.322570][ C0] do_idle+0x393/0x690 [ 62.327247][ C0] cpu_startup_entry+0x14/0x20 [ 62.332190][ C0] start_kernel+0x867/0x8a1 [ 62.336849][ C0] secondary_startup_64+0xa4/0xb0 [ 62.342071][ C0] [ 62.344676][ C0] [ 62.344676][ C0] stack backtrace: [ 62.351163][ C0] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.6.0-syzkaller #0 [ 62.359395][ C0] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 62.370681][ C0] Call Trace: [ 62.374521][ C0] [ 62.378317][ C0] dump_stack+0x188/0x20d [ 62.382794][ C0] check_usage_forwards.cold+0x20/0x29 [ 62.388646][ C0] ? check_usage_backwards+0x4e0/0x4e0 [ 62.394593][ C0] ? stack_trace_consume_entry+0x160/0x160 [ 62.400507][ C0] ? __read_once_size_nocheck.constprop.0+0x10/0x10 [ 62.407073][ C0] ? save_trace+0x42/0x9f0 [ 62.411476][ C0] mark_lock+0x624/0xf10 [ 62.415887][ C0] ? check_usage_backwards+0x4e0/0x4e0 [ 62.421324][ C0] ? print_usage_bug+0x240/0x240 [ 62.426351][ C0] ? print_usage_bug+0x240/0x240 [ 62.431278][ C0] ? mark_lock+0x12b/0xf10 [ 62.435790][ C0] __lock_acquire+0x1d28/0x4e00 [ 62.441432][ C0] ? mark_held_locks+0xe0/0xe0 [ 62.446183][ C0] ? __wake_up_common_lock+0xde/0x130 [ 62.453028][ C0] lock_acquire+0x1f2/0x8f0 [ 62.457533][ C0] ? free_ioctx_users+0x2b/0x450 [ 62.462473][ C0] ? lock_release+0x800/0x800 [ 62.467308][ C0] ? lock_acquire+0x1f2/0x8f0 [ 62.472068][ C0] ? percpu_ref_switch_to_atomic_rcu+0x209/0x540 [ 62.478477][ C0] ? lock_release+0x800/0x800 [ 62.483138][ C0] ? _raw_spin_unlock_irqrestore+0x62/0xe0 [ 62.488921][ C0] _raw_spin_lock_irq+0x5b/0x80 [ 62.493888][ C0] ? free_ioctx_users+0x2b/0x450 [ 62.498831][ C0] free_ioctx_users+0x2b/0x450 [ 62.503789][ C0] percpu_ref_switch_to_atomic_rcu+0x494/0x540 [ 62.509937][ C0] rcu_core+0x59f/0x1370 [ 62.514411][ C0] ? __rcu_read_unlock+0x700/0x700 [ 62.519611][ C0] ? rcu_read_lock_sched_held+0x9c/0xd0 [ 62.525283][ C0] ? rcu_read_lock_any_held.part.0+0x50/0x50 [ 62.531454][ C0] ? run_rebalance_domains+0x202/0x2c0 [ 62.537601][ C0] __do_softirq+0x26c/0x9f7 [ 62.542286][ C0] irq_exit+0x192/0x1d0 [ 62.546532][ C0] smp_apic_timer_interrupt+0x19e/0x600 [ 62.552080][ C0] apic_timer_interrupt+0xf/0x20 [ 62.557079][ C0] [ 62.560144][ C0] RIP: 0010:native_safe_halt+0xe/0x10 [ 62.565498][ C0] Code: cc cc cc cc cc cc cc cc cc cc cc cc e9 07 00 00 00 0f 00 2d d4 f2 59 00 f4 c3 66 90 e9 07 00 00 00 0f 00 2d c4 f2 59 00 fb f4 cc 41 56 41 55 41 54 55 53 e8 33 77 92 f9 e8 3e b3 ca fb 0f 1f [ 62.585146][ C0] RSP: 0018:ffffffff89807d98 EFLAGS: 00000286 ORIG_RAX: ffffffffffffff13 [ 62.593614][ C0] RAX: 1ffffffff132925f RBX: ffffffff898864c0 RCX: 0000000000000000 [ 62.603439][ C0] RDX: dffffc0000000000 RSI: 0000000000000006 RDI: ffffffff89886d84 [ 62.611410][ C0] RBP: dffffc0000000000 R08: ffffffff898864c0 R09: 0000000000000000 [ 62.619608][ C0] R10: 0000000000000000 R11: 0000000000000000 R12: fffffbfff1310c98 [ 62.628180][ C0] R13: 0000000000000000 R14: ffffffff8a88e980 R15: 0000000000000000 [ 62.636170][ C0] default_idle+0x49/0x350 [ 62.640569][ C0] do_idle+0x393/0x690 [ 62.644631][ C0] ? arch_cpu_idle_exit+0x70/0x70 [ 62.649640][ C0] ? trace_init_perf_perm_irq_work_exit+0xe/0xe [ 62.655874][ C0]