[ OK ] Reached target Multi-User System. [ OK ] Reached target Graphical Interface. Starting Update UTMP about System Runlevel Changes... [ OK ] Started Load/Save RF Kill Switch Status. [ OK ] Started Update UTMP about System Runlevel Changes. Debian GNU/Linux 9 syzkaller ttyS0 Warning: Permanently added '10.128.0.79' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 61.623058][ C1] [ 61.625528][ C1] ======================================================== [ 61.632700][ C1] WARNING: possible irq lock inversion dependency detected [ 61.640468][ C1] 5.6.0-syzkaller #0 Not tainted [ 61.645393][ C1] -------------------------------------------------------- [ 61.652563][ C1] swapper/1/0 just changed the state of lock: [ 61.658609][ C1] ffff888093f95cd8 (&ctx->ctx_lock){..-.}-{2:2}, at: free_ioctx_users+0x2b/0x450 [ 61.670315][ C1] but this lock took another, SOFTIRQ-unsafe lock in the past: [ 61.677857][ C1] (&pid->wait_pidfd){+.+.}-{2:2} [ 61.677864][ C1] [ 61.677864][ C1] [ 61.677864][ C1] and interrupts could create inverse lock ordering between them. [ 61.677864][ C1] [ 61.697237][ C1] [ 61.697237][ C1] other info that might help us debug this: [ 61.705401][ C1] Possible interrupt unsafe locking scenario: [ 61.705401][ C1] [ 61.713735][ C1] CPU0 CPU1 [ 61.719079][ C1] ---- ---- [ 61.724420][ C1] lock(&pid->wait_pidfd); [ 61.728903][ C1] local_irq_disable(); [ 61.735724][ C1] lock(&ctx->ctx_lock); [ 61.742551][ C1] lock(&pid->wait_pidfd); [ 61.749546][ C1] [ 61.752975][ C1] lock(&ctx->ctx_lock); [ 61.757570][ C1] [ 61.757570][ C1] *** DEADLOCK *** [ 61.757570][ C1] [ 61.765699][ C1] 2 locks held by swapper/1/0: [ 61.770438][ C1] #0: ffffffff899bc060 (rcu_callback){....}-{0:0}, at: rcu_core+0x520/0x1370 [ 61.779281][ C1] #1: ffffffff899bc180 (rcu_read_lock){....}-{1:2}, at: percpu_ref_switch_to_atomic_rcu+0x209/0x540 [ 61.790118][ C1] [ 61.790118][ C1] the shortest dependencies between 2nd lock and 1st lock: [ 61.800444][ C1] -> (&pid->wait_pidfd){+.+.}-{2:2} { [ 61.805887][ C1] HARDIRQ-ON-W at: [ 61.809943][ C1] lock_acquire+0x1f2/0x8f0 [ 61.816245][ C1] _raw_spin_lock+0x2a/0x40 [ 61.822546][ C1] proc_pid_make_inode+0x1f9/0x3c0 [ 61.829640][ C1] proc_pid_instantiate+0x51/0x150 [ 61.836751][ C1] proc_pid_lookup+0x1da/0x340 [ 61.843508][ C1] proc_root_lookup+0x20/0x60 [ 61.849988][ C1] __lookup_slow+0x256/0x490 [ 61.856396][ C1] walk_component+0x418/0x6a0 [ 61.862875][ C1] link_path_walk.part.0+0x4f1/0xb50 [ 61.869958][ C1] path_openat+0x25a/0x27d0 [ 61.876450][ C1] do_filp_open+0x192/0x260 [ 61.882762][ C1] do_sys_openat2+0x585/0x7d0 [ 61.889234][ C1] do_sys_open+0xc3/0x140 [ 61.895362][ C1] do_syscall_64+0xf6/0x7d0 [ 61.901663][ C1] entry_SYSCALL_64_after_hwframe+0x49/0xb3 [ 61.909349][ C1] SOFTIRQ-ON-W at: [ 61.913394][ C1] lock_acquire+0x1f2/0x8f0 [ 61.919701][ C1] _raw_spin_lock+0x2a/0x40 [ 61.926040][ C1] proc_pid_make_inode+0x1f9/0x3c0 [ 61.932994][ C1] proc_pid_instantiate+0x51/0x150 [ 61.939933][ C1] proc_pid_lookup+0x1da/0x340 [ 61.946512][ C1] proc_root_lookup+0x20/0x60 [ 61.953608][ C1] __lookup_slow+0x256/0x490 [ 61.960027][ C1] walk_component+0x418/0x6a0 [ 61.966603][ C1] link_path_walk.part.0+0x4f1/0xb50 [ 61.973878][ C1] path_openat+0x25a/0x27d0 [ 61.980182][ C1] do_filp_open+0x192/0x260 [ 61.986483][ C1] do_sys_openat2+0x585/0x7d0 [ 61.992958][ C1] do_sys_open+0xc3/0x140 [ 61.999085][ C1] do_syscall_64+0xf6/0x7d0 [ 62.005482][ C1] entry_SYSCALL_64_after_hwframe+0x49/0xb3 [ 62.013177][ C1] INITIAL USE at: [ 62.017137][ C1] lock_acquire+0x1f2/0x8f0 [ 62.023533][ C1] _raw_spin_lock_irqsave+0x8c/0xbf [ 62.030449][ C1] __wake_up_common_lock+0xb4/0x130 [ 62.037355][ C1] do_notify_parent+0x19e/0xe60 [ 62.043932][ C1] do_exit+0x238f/0x2dd0 [ 62.050411][ C1] call_usermodehelper_exec_async+0x507/0x710 [ 62.059120][ C1] ret_from_fork+0x24/0x30 [ 62.065247][ C1] } [ 62.067838][ C1] ... key at: [] __key.53831+0x0/0x40 [ 62.075531][ C1] ... acquired at: [ 62.079446][ C1] _raw_spin_lock+0x2a/0x40 [ 62.084123][ C1] io_submit_one+0xc1b/0x2ec0 [ 62.088964][ C1] __ia32_compat_sys_io_submit+0x1bf/0x530 [ 62.094918][ C1] do_fast_syscall_32+0x270/0xe90 [ 62.100090][ C1] entry_SYSENTER_compat+0x70/0x7f [ 62.105343][ C1] [ 62.107782][ C1] -> (&ctx->ctx_lock){..-.}-{2:2} { [ 62.112969][ C1] IN-SOFTIRQ-W at: [ 62.117030][ C1] lock_acquire+0x1f2/0x8f0 [ 62.123171][ C1] _raw_spin_lock_irq+0x5b/0x80 [ 62.129830][ C1] free_ioctx_users+0x2b/0x450 [ 62.136249][ C1] percpu_ref_switch_to_atomic_rcu+0x494/0x540 [ 62.144051][ C1] rcu_core+0x59f/0x1370 [ 62.149962][ C1] __do_softirq+0x26c/0x9f7 [ 62.156261][ C1] irq_exit+0x192/0x1d0 [ 62.162589][ C1] smp_apic_timer_interrupt+0x19e/0x600 [ 62.170054][ C1] apic_timer_interrupt+0xf/0x20 [ 62.176636][ C1] native_safe_halt+0xe/0x10 [ 62.182880][ C1] default_idle+0x49/0x350 [ 62.189080][ C1] do_idle+0x393/0x690 [ 62.194915][ C1] cpu_startup_entry+0x14/0x20 [ 62.202015][ C1] start_secondary+0x2f3/0x400 [ 62.208414][ C1] secondary_startup_64+0xa4/0xb0 [ 62.215074][ C1] INITIAL USE at: [ 62.218967][ C1] lock_acquire+0x1f2/0x8f0 [ 62.225016][ C1] _raw_spin_lock_irq+0x5b/0x80 [ 62.231503][ C1] io_submit_one+0xbd6/0x2ec0 [ 62.237719][ C1] __ia32_compat_sys_io_submit+0x1bf/0x530 [ 62.247277][ C1] do_fast_syscall_32+0x270/0xe90 [ 62.253853][ C1] entry_SYSENTER_compat+0x70/0x7f [ 62.260506][ C1] } [ 62.263009][ C1] ... key at: [] __key.55314+0x0/0x40 [ 62.270434][ C1] ... acquired at: [ 62.274226][ C1] mark_lock+0x624/0xf10 [ 62.278708][ C1] __lock_acquire+0x1d28/0x4e00 [ 62.283826][ C1] lock_acquire+0x1f2/0x8f0 [ 62.288506][ C1] _raw_spin_lock_irq+0x5b/0x80 [ 62.293511][ C1] free_ioctx_users+0x2b/0x450 [ 62.298452][ C1] percpu_ref_switch_to_atomic_rcu+0x494/0x540 [ 62.304771][ C1] rcu_core+0x59f/0x1370 [ 62.309259][ C1] __do_softirq+0x26c/0x9f7 [ 62.313922][ C1] irq_exit+0x192/0x1d0 [ 62.318229][ C1] smp_apic_timer_interrupt+0x19e/0x600 [ 62.323962][ C1] apic_timer_interrupt+0xf/0x20 [ 62.329051][ C1] native_safe_halt+0xe/0x10 [ 62.333805][ C1] default_idle+0x49/0x350 [ 62.339020][ C1] do_idle+0x393/0x690 [ 62.343252][ C1] cpu_startup_entry+0x14/0x20 [ 62.348229][ C1] start_secondary+0x2f3/0x400 [ 62.353147][ C1] secondary_startup_64+0xa4/0xb0 [ 62.359878][ C1] [ 62.362196][ C1] [ 62.362196][ C1] stack backtrace: [ 62.368215][ C1] CPU: 1 PID: 0 Comm: swapper/1 Not tainted 5.6.0-syzkaller #0 [ 62.375755][ C1] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 62.385922][ C1] Call Trace: [ 62.389190][ C1] [ 62.392025][ C1] dump_stack+0x188/0x20d [ 62.396452][ C1] check_usage_forwards.cold+0x20/0x29 [ 62.402024][ C1] ? check_usage_backwards+0x4e0/0x4e0 [ 62.407478][ C1] ? stack_trace_consume_entry+0x160/0x160 [ 62.413276][ C1] ? __read_once_size_nocheck.constprop.0+0x10/0x10 [ 62.419869][ C1] ? get_stack_info+0x32/0x13e [ 62.424624][ C1] ? save_trace+0x42/0x9f0 [ 62.429045][ C1] mark_lock+0x624/0xf10 [ 62.433288][ C1] ? check_usage_backwards+0x4e0/0x4e0 [ 62.438746][ C1] ? print_usage_bug+0x240/0x240 [ 62.443676][ C1] ? print_usage_bug+0x240/0x240 [ 62.448593][ C1] ? mark_lock+0x12b/0xf10 [ 62.452994][ C1] __lock_acquire+0x1d28/0x4e00 [ 62.457862][ C1] ? mark_held_locks+0xe0/0xe0 [ 62.462715][ C1] ? __wake_up_common_lock+0xde/0x130 [ 62.468073][ C1] lock_acquire+0x1f2/0x8f0 [ 62.472601][ C1] ? free_ioctx_users+0x2b/0x450 [ 62.477532][ C1] ? lock_release+0x800/0x800 [ 62.482204][ C1] ? lock_acquire+0x1f2/0x8f0 [ 62.486977][ C1] ? percpu_ref_switch_to_atomic_rcu+0x209/0x540 [ 62.493316][ C1] ? lock_release+0x800/0x800 [ 62.498005][ C1] ? _raw_spin_unlock_irqrestore+0x62/0xe0 [ 62.503884][ C1] _raw_spin_lock_irq+0x5b/0x80 [ 62.508725][ C1] ? free_ioctx_users+0x2b/0x450 [ 62.513654][ C1] free_ioctx_users+0x2b/0x450 [ 62.518431][ C1] percpu_ref_switch_to_atomic_rcu+0x494/0x540 [ 62.524578][ C1] rcu_core+0x59f/0x1370 [ 62.528831][ C1] ? __rcu_read_unlock+0x700/0x700 [ 62.533962][ C1] ? rcu_read_lock_sched_held+0x9c/0xd0 [ 62.539505][ C1] ? rcu_read_lock_any_held.part.0+0x50/0x50 [ 62.545467][ C1] ? run_rebalance_domains+0x202/0x2c0 [ 62.551037][ C1] __do_softirq+0x26c/0x9f7 [ 62.555588][ C1] irq_exit+0x192/0x1d0 [ 62.559725][ C1] smp_apic_timer_interrupt+0x19e/0x600 [ 62.565263][ C1] apic_timer_interrupt+0xf/0x20 [ 62.570205][ C1] [ 62.573148][ C1] RIP: 0010:native_safe_halt+0xe/0x10 [ 62.579305][ C1] Code: cc cc cc cc cc cc cc cc cc cc cc cc e9 07 00 00 00 0f 00 2d 84 1e 59 00 f4 c3 66 90 e9 07 00 00 00 0f 00 2d 74 1e 59 00 fb f4 cc 41 56 41 55 41 54 55 53 e8 83 91 91 f9 e8 ce 2c ca fb 0f 1f [ 62.598904][ C1] RSP: 0018:ffffc90000d3fdb8 EFLAGS: 00000286 ORIG_RAX: ffffffffffffff13 [ 62.607315][ C1] RAX: 1ffffffff132930f RBX: ffff8880a95f2340 RCX: 0000000000000000 [ 62.615275][ C1] RDX: dffffc0000000000 RSI: 0000000000000006 RDI: ffff8880a95f2c04 [ 62.623235][ C1] RBP: dffffc0000000000 R08: ffff8880a95f2340 R09: 0000000000000000 [ 62.631200][ C1] R10: 0000000000000000 R11: 0000000000000000 R12: ffffed10152be468 [ 62.639307][ C1] R13: 0000000000000001 R14: ffffffff8a890cc0 R15: 0000000000000000 [ 62.647315][ C1] default_idle+0x49/0x350 [ 62.651900][ C1] do_idle+0x393/0x690 [ 62.656207][ C1] ? arch_cpu_idle_exit+0x70/0x70 [ 62.661245][ C1] ? _raw_spin_unlock_irqrestore+0x62/0xe0 [ 62.667048][ C1] ? lockdep_hardirqs_on+0x463/0x620 [ 62.672383][ C1] cpu_startup_entry+0x14/0x20 [ 62.677422][ C1] start_secondary+0x2f3/0x400 [ 62.682226][ C1] ? set_cpu_sibling_map+0x1ed0/0x1ed0 [ 62.688019][ C1] secondary_startup_64+0xa4/0xb0