[ OK ] Started Getty on tty3. [ OK ] Started Getty on tty2. [ OK ] Started Getty on tty1. [ OK ] Started Serial Getty on ttyS0. [ OK ] Reached target Login Prompts. [ OK ] Reached target Multi-User System. [ OK ] Reached target Graphical Interface. Starting Update UTMP about System Runlevel Changes... [ OK ] Started Update UTMP about System Runlevel Changes. Starting Load/Save RF Kill Switch Status... [ OK ] Started Load/Save RF Kill Switch Status. Debian GNU/Linux 9 syzkaller ttyS0 Warning: Permanently added '10.128.0.157' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 59.561443][ C1] [ 59.563780][ C1] ======================================================== [ 59.570938][ C1] WARNING: possible irq lock inversion dependency detected [ 59.578800][ C1] 5.6.0-syzkaller #0 Not tainted [ 59.583714][ C1] -------------------------------------------------------- [ 59.590890][ C1] swapper/1/0 just changed the state of lock: [ 59.596937][ C1] ffff88809720dcd8 (&ctx->ctx_lock){..-.}-{2:2}, at: free_ioctx_users+0x2b/0x450 [ 59.606032][ C1] but this lock took another, SOFTIRQ-unsafe lock in the past: [ 59.613543][ C1] (&pid->wait_pidfd){+.+.}-{2:2} [ 59.613552][ C1] [ 59.613552][ C1] [ 59.613552][ C1] and interrupts could create inverse lock ordering between them. [ 59.613552][ C1] [ 59.632834][ C1] [ 59.632834][ C1] other info that might help us debug this: [ 59.640907][ C1] Possible interrupt unsafe locking scenario: [ 59.640907][ C1] [ 59.649211][ C1] CPU0 CPU1 [ 59.654580][ C1] ---- ---- [ 59.659923][ C1] lock(&pid->wait_pidfd); [ 59.664404][ C1] local_irq_disable(); [ 59.671172][ C1] lock(&ctx->ctx_lock); [ 59.677994][ C1] lock(&pid->wait_pidfd); [ 59.684993][ C1] [ 59.688463][ C1] lock(&ctx->ctx_lock); [ 59.692980][ C1] [ 59.692980][ C1] *** DEADLOCK *** [ 59.692980][ C1] [ 59.701148][ C1] 2 locks held by swapper/1/0: [ 59.705880][ C1] #0: ffffffff899bbaa0 (rcu_callback){....}-{0:0}, at: rcu_core+0x520/0x1370 [ 59.714711][ C1] #1: ffffffff899bbbc0 (rcu_read_lock){....}-{1:2}, at: percpu_ref_switch_to_atomic_rcu+0x209/0x540 [ 59.725545][ C1] [ 59.725545][ C1] the shortest dependencies between 2nd lock and 1st lock: [ 59.734898][ C1] -> (&pid->wait_pidfd){+.+.}-{2:2} { [ 59.740351][ C1] HARDIRQ-ON-W at: [ 59.744402][ C1] lock_acquire+0x1f2/0x8f0 [ 59.750702][ C1] _raw_spin_lock+0x2a/0x40 [ 59.757003][ C1] proc_pid_make_inode+0x1f9/0x3c0 [ 59.763913][ C1] proc_pid_instantiate+0x51/0x150 [ 59.770834][ C1] proc_pid_lookup+0x1da/0x340 [ 59.777396][ C1] proc_root_lookup+0x20/0x60 [ 59.783873][ C1] __lookup_slow+0x256/0x490 [ 59.790277][ C1] walk_component+0x418/0x6a0 [ 59.796754][ C1] link_path_walk.part.0+0x4f1/0xb50 [ 59.803845][ C1] path_openat+0x25a/0x27d0 [ 59.810142][ C1] do_filp_open+0x192/0x260 [ 59.816456][ C1] do_sys_openat2+0x585/0x7d0 [ 59.822932][ C1] do_sys_open+0xc3/0x140 [ 59.829071][ C1] do_syscall_64+0xf6/0x7d0 [ 59.835387][ C1] entry_SYSCALL_64_after_hwframe+0x49/0xb3 [ 59.843088][ C1] SOFTIRQ-ON-W at: [ 59.847148][ C1] lock_acquire+0x1f2/0x8f0 [ 59.853455][ C1] _raw_spin_lock+0x2a/0x40 [ 59.859762][ C1] proc_pid_make_inode+0x1f9/0x3c0 [ 59.866671][ C1] proc_pid_instantiate+0x51/0x150 [ 59.873581][ C1] proc_pid_lookup+0x1da/0x340 [ 59.880142][ C1] proc_root_lookup+0x20/0x60 [ 59.886619][ C1] __lookup_slow+0x256/0x490 [ 59.893012][ C1] walk_component+0x418/0x6a0 [ 59.899495][ C1] link_path_walk.part.0+0x4f1/0xb50 [ 59.906578][ C1] path_openat+0x25a/0x27d0 [ 59.912882][ C1] do_filp_open+0x192/0x260 [ 59.919205][ C1] do_sys_openat2+0x585/0x7d0 [ 59.925681][ C1] do_sys_open+0xc3/0x140 [ 59.931921][ C1] do_syscall_64+0xf6/0x7d0 [ 59.938234][ C1] entry_SYSCALL_64_after_hwframe+0x49/0xb3 [ 59.945933][ C1] INITIAL USE at: [ 59.949898][ C1] lock_acquire+0x1f2/0x8f0 [ 59.956117][ C1] _raw_spin_lock_irqsave+0x8c/0xbf [ 59.963152][ C1] __wake_up_common_lock+0xb4/0x130 [ 59.970081][ C1] do_notify_parent+0x19e/0xe60 [ 59.976650][ C1] do_exit+0x238f/0x2dd0 [ 59.982627][ C1] call_usermodehelper_exec_async+0x507/0x710 [ 59.990432][ C1] ret_from_fork+0x24/0x30 [ 59.996575][ C1] } [ 59.999146][ C1] ... key at: [] __key.53786+0x0/0x40 [ 60.006674][ C1] ... acquired at: [ 60.010548][ C1] _raw_spin_lock+0x2a/0x40 [ 60.015199][ C1] io_submit_one+0xc1b/0x2ec0 [ 60.020024][ C1] __ia32_compat_sys_io_submit+0x1bf/0x530 [ 60.025977][ C1] do_fast_syscall_32+0x270/0xe90 [ 60.031148][ C1] entry_SYSENTER_compat+0x70/0x7f [ 60.036410][ C1] [ 60.038721][ C1] -> (&ctx->ctx_lock){..-.}-{2:2} { [ 60.043898][ C1] IN-SOFTIRQ-W at: [ 60.047860][ C1] lock_acquire+0x1f2/0x8f0 [ 60.054005][ C1] _raw_spin_lock_irq+0x5b/0x80 [ 60.060611][ C1] free_ioctx_users+0x2b/0x450 [ 60.067009][ C1] percpu_ref_switch_to_atomic_rcu+0x494/0x540 [ 60.074797][ C1] rcu_core+0x59f/0x1370 [ 60.080703][ C1] __do_softirq+0x26c/0x9f7 [ 60.086833][ C1] irq_exit+0x192/0x1d0 [ 60.092623][ C1] smp_apic_timer_interrupt+0x19e/0x600 [ 60.099798][ C1] apic_timer_interrupt+0xf/0x20 [ 60.106400][ C1] native_safe_halt+0xe/0x10 [ 60.112617][ C1] default_idle+0x49/0x350 [ 60.118655][ C1] do_idle+0x393/0x690 [ 60.124389][ C1] cpu_startup_entry+0x14/0x20 [ 60.130811][ C1] start_secondary+0x2f3/0x400 [ 60.137208][ C1] secondary_startup_64+0xa4/0xb0 [ 60.143850][ C1] INITIAL USE at: [ 60.147733][ C1] lock_acquire+0x1f2/0x8f0 [ 60.153771][ C1] _raw_spin_lock_irq+0x5b/0x80 [ 60.160159][ C1] io_submit_one+0xbd6/0x2ec0 [ 60.166371][ C1] __ia32_compat_sys_io_submit+0x1bf/0x530 [ 60.173716][ C1] do_fast_syscall_32+0x270/0xe90 [ 60.180278][ C1] entry_SYSENTER_compat+0x70/0x7f [ 60.186917][ C1] } [ 60.189396][ C1] ... key at: [] __key.55262+0x0/0x40 [ 60.196826][ C1] ... acquired at: [ 60.200610][ C1] mark_lock+0x624/0xf10 [ 60.205011][ C1] __lock_acquire+0x1d28/0x4e00 [ 60.210017][ C1] lock_acquire+0x1f2/0x8f0 [ 60.214679][ C1] _raw_spin_lock_irq+0x5b/0x80 [ 60.219725][ C1] free_ioctx_users+0x2b/0x450 [ 60.224653][ C1] percpu_ref_switch_to_atomic_rcu+0x494/0x540 [ 60.230954][ C1] rcu_core+0x59f/0x1370 [ 60.235345][ C1] __do_softirq+0x26c/0x9f7 [ 60.239995][ C1] irq_exit+0x192/0x1d0 [ 60.244296][ C1] smp_apic_timer_interrupt+0x19e/0x600 [ 60.250107][ C1] apic_timer_interrupt+0xf/0x20 [ 60.255215][ C1] native_safe_halt+0xe/0x10 [ 60.259951][ C1] default_idle+0x49/0x350 [ 60.264512][ C1] do_idle+0x393/0x690 [ 60.268739][ C1] cpu_startup_entry+0x14/0x20 [ 60.273650][ C1] start_secondary+0x2f3/0x400 [ 60.278575][ C1] secondary_startup_64+0xa4/0xb0 [ 60.283754][ C1] [ 60.286055][ C1] [ 60.286055][ C1] stack backtrace: [ 60.291933][ C1] CPU: 1 PID: 0 Comm: swapper/1 Not tainted 5.6.0-syzkaller #0 [ 60.299443][ C1] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 60.309477][ C1] Call Trace: [ 60.312736][ C1] [ 60.315589][ C1] dump_stack+0x188/0x20d [ 60.319900][ C1] check_usage_forwards.cold+0x20/0x29 [ 60.325345][ C1] ? check_usage_backwards+0x4e0/0x4e0 [ 60.330781][ C1] ? stack_trace_consume_entry+0x160/0x160 [ 60.336589][ C1] ? __read_once_size_nocheck.constprop.0+0x10/0x10 [ 60.343166][ C1] ? get_stack_info+0x32/0x13e [ 60.347915][ C1] ? save_trace+0x42/0x9f0 [ 60.352347][ C1] mark_lock+0x624/0xf10 [ 60.356565][ C1] ? check_usage_backwards+0x4e0/0x4e0 [ 60.362030][ C1] ? print_usage_bug+0x240/0x240 [ 60.366939][ C1] ? print_usage_bug+0x240/0x240 [ 60.371856][ C1] ? mark_lock+0x12b/0xf10 [ 60.376242][ C1] __lock_acquire+0x1d28/0x4e00 [ 60.381065][ C1] ? mark_held_locks+0xe0/0xe0 [ 60.385804][ C1] ? __wake_up_common_lock+0xde/0x130 [ 60.391151][ C1] lock_acquire+0x1f2/0x8f0 [ 60.395642][ C1] ? free_ioctx_users+0x2b/0x450 [ 60.400562][ C1] ? lock_release+0x800/0x800 [ 60.405231][ C1] ? lock_acquire+0x1f2/0x8f0 [ 60.409884][ C1] ? percpu_ref_switch_to_atomic_rcu+0x209/0x540 [ 60.416186][ C1] ? lock_release+0x800/0x800 [ 60.420836][ C1] ? _raw_spin_unlock_irqrestore+0x62/0xe0 [ 60.426620][ C1] _raw_spin_lock_irq+0x5b/0x80 [ 60.431462][ C1] ? free_ioctx_users+0x2b/0x450 [ 60.436372][ C1] free_ioctx_users+0x2b/0x450 [ 60.441112][ C1] percpu_ref_switch_to_atomic_rcu+0x494/0x540 [ 60.447240][ C1] rcu_core+0x59f/0x1370 [ 60.451457][ C1] ? __rcu_read_unlock+0x700/0x700 [ 60.456543][ C1] ? rcu_read_lock_sched_held+0x9c/0xd0 [ 60.462070][ C1] ? rcu_read_lock_any_held.part.0+0x50/0x50 [ 60.468021][ C1] ? run_rebalance_domains+0x202/0x2c0 [ 60.473452][ C1] __do_softirq+0x26c/0x9f7 [ 60.477941][ C1] irq_exit+0x192/0x1d0 [ 60.482070][ C1] smp_apic_timer_interrupt+0x19e/0x600 [ 60.487591][ C1] apic_timer_interrupt+0xf/0x20 [ 60.492497][ C1] [ 60.495412][ C1] RIP: 0010:native_safe_halt+0xe/0x10 [ 60.500755][ C1] Code: cc cc cc cc cc cc cc cc cc cc cc cc e9 07 00 00 00 0f 00 2d a4 4d 5a 00 f4 c3 66 90 e9 07 00 00 00 0f 00 2d 94 4d 5a 00 fb f4 cc 41 56 41 55 41 54 55 53 e8 e3 d1 92 f9 e8 2e 9f ca fb 0f 1f [ 60.520344][ C1] RSP: 0018:ffffc90000d3fdb8 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff13 [ 60.528743][ C1] RAX: 1ffffffff132925f RBX: ffff8880a95f2340 RCX: 0000000000000000 [ 60.536700][ C1] RDX: dffffc0000000000 RSI: 0000000000000006 RDI: ffff8880a95f2c04 [ 60.545001][ C1] RBP: dffffc0000000000 R08: ffff8880a95f2340 R09: 0000000000000000 [ 60.553941][ C1] R10: 0000000000000000 R11: 0000000000000000 R12: ffffed10152be468 [ 60.561889][ C1] R13: 0000000000000001 R14: ffffffff8a88df40 R15: 0000000000000000 [ 60.569857][ C1] default_idle+0x49/0x350 [ 60.574322][ C1] do_idle+0x393/0x690 [ 60.578374][ C1] ? arch_cpu_idle_exit+0x70/0x70 [ 60.583379][ C1] ? _raw_spin_unlock_irqrestore+0x62/0xe0 [ 60.589166][ C1] ? lockdep_hardirqs_on+0x463/0x620 [ 60.594429][ C1] cpu_startup_entry+0x14/0x20 [ 60.599169][ C1] start_secondary+0x2f3/0x400 [ 60.603924][ C1] ? set_cpu_sibling_map+0x1ed0/0x1ed0 [ 60.609397][ C1] secondary_startup_64+0xa4/0xb0