Warning: Permanently added '10.128.0.229' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 61.875409][ T7040] nf_conntrack: default automatic helper assignment has been turned off for security reasons and CT-based firewall rule not found. Use the iptables CT target to attach helpers instead. [ 61.962602][ C1] [ 61.964999][ C1] ======================================================== [ 61.972167][ C1] WARNING: possible irq lock inversion dependency detected [ 61.979348][ C1] 5.6.0-syzkaller #0 Not tainted [ 61.984274][ C1] -------------------------------------------------------- [ 61.991454][ C1] swapper/1/0 just changed the state of lock: [ 61.997501][ C1] ffffffff898090d8 (tasklist_lock){.+.?}-{2:2}, at: send_sigurg+0x9f/0x320 [ 62.007025][ C1] but this lock took another, SOFTIRQ-unsafe lock in the past: [ 62.014544][ C1] (&pid->wait_pidfd){+.+.}-{2:2} [ 62.014551][ C1] [ 62.014551][ C1] [ 62.014551][ C1] and interrupts could create inverse lock ordering between them. [ 62.014551][ C1] [ 62.034013][ C1] [ 62.034013][ C1] other info that might help us debug this: [ 62.042047][ C1] Possible interrupt unsafe locking scenario: [ 62.042047][ C1] [ 62.050350][ C1] CPU0 CPU1 [ 62.055695][ C1] ---- ---- [ 62.061043][ C1] lock(&pid->wait_pidfd); [ 62.065528][ C1] local_irq_disable(); [ 62.072279][ C1] lock(tasklist_lock); [ 62.079019][ C1] lock(&pid->wait_pidfd); [ 62.086023][ C1] [ 62.089452][ C1] lock(tasklist_lock); [ 62.093843][ C1] [ 62.093843][ C1] *** DEADLOCK *** [ 62.093843][ C1] [ 62.102077][ C1] 4 locks held by swapper/1/0: [ 62.106858][ C1] #0: ffffffff899bacc0 (rcu_read_lock){....}-{1:2}, at: process_backlog+0x1ad/0x7a0 [ 62.116321][ C1] #1: ffffffff899bacc0 (rcu_read_lock){....}-{1:2}, at: ip_local_deliver_finish+0x124/0x360 [ 62.126467][ C1] #2: ffff888093e42de0 (slock-AF_INET/1){+.-.}-{2:2}, at: tcp_v4_rcv+0x2d09/0x39c0 [ 62.135829][ C1] #3: ffff8880950c23b8 (&f->f_owner.lock){.+.?}-{2:2}, at: send_sigurg+0x1a/0x320 [ 62.145097][ C1] [ 62.145097][ C1] the shortest dependencies between 2nd lock and 1st lock: [ 62.154451][ C1] -> (&pid->wait_pidfd){+.+.}-{2:2} { [ 62.159885][ C1] HARDIRQ-ON-W at: [ 62.163940][ C1] lock_acquire+0x1f2/0x8f0 [ 62.170240][ C1] _raw_spin_lock+0x2a/0x40 [ 62.176540][ C1] proc_pid_make_inode+0x1f9/0x3c0 [ 62.183468][ C1] proc_pid_instantiate+0x51/0x150 [ 62.190395][ C1] proc_pid_lookup+0x1da/0x340 [ 62.196977][ C1] proc_root_lookup+0x20/0x60 [ 62.203459][ C1] __lookup_slow+0x256/0x490 [ 62.209858][ C1] walk_component+0x418/0x6a0 [ 62.216368][ C1] link_path_walk.part.0+0x4f1/0xb50 [ 62.223496][ C1] path_openat+0x25a/0x27b0 [ 62.229809][ C1] do_filp_open+0x203/0x260 [ 62.236184][ C1] do_sys_openat2+0x585/0x770 [ 62.242714][ C1] do_sys_open+0xc3/0x140 [ 62.248844][ C1] do_syscall_64+0xf6/0x7d0 [ 62.255149][ C1] entry_SYSCALL_64_after_hwframe+0x49/0xb3 [ 62.262837][ C1] SOFTIRQ-ON-W at: [ 62.266883][ C1] lock_acquire+0x1f2/0x8f0 [ 62.273191][ C1] _raw_spin_lock+0x2a/0x40 [ 62.279491][ C1] proc_pid_make_inode+0x1f9/0x3c0 [ 62.286416][ C1] proc_pid_instantiate+0x51/0x150 [ 62.293333][ C1] proc_pid_lookup+0x1da/0x340 [ 62.299928][ C1] proc_root_lookup+0x20/0x60 [ 62.306422][ C1] __lookup_slow+0x256/0x490 [ 62.312827][ C1] walk_component+0x418/0x6a0 [ 62.319314][ C1] link_path_walk.part.0+0x4f1/0xb50 [ 62.326411][ C1] path_openat+0x25a/0x27b0 [ 62.332712][ C1] do_filp_open+0x203/0x260 [ 62.339010][ C1] do_sys_openat2+0x585/0x770 [ 62.345484][ C1] do_sys_open+0xc3/0x140 [ 62.351611][ C1] do_syscall_64+0xf6/0x7d0 [ 62.357922][ C1] entry_SYSCALL_64_after_hwframe+0x49/0xb3 [ 62.365604][ C1] INITIAL USE at: [ 62.369560][ C1] lock_acquire+0x1f2/0x8f0 [ 62.375783][ C1] _raw_spin_lock_irqsave+0x8c/0xbf [ 62.382690][ C1] __wake_up_common_lock+0xb4/0x130 [ 62.389599][ C1] do_notify_parent+0x19e/0xe60 [ 62.396163][ C1] do_exit+0x238f/0x2dd0 [ 62.402130][ C1] call_usermodehelper_exec_async+0x507/0x710 [ 62.410128][ C1] ret_from_fork+0x24/0x30 [ 62.417404][ C1] } [ 62.420162][ C1] ... key at: [] __key.53714+0x0/0x40 [ 62.427693][ C1] ... acquired at: [ 62.432181][ C1] _raw_spin_lock_irqsave+0x8c/0xbf [ 62.441202][ C1] __wake_up_common_lock+0xb4/0x130 [ 62.446581][ C1] do_notify_parent+0x19e/0xe60 [ 62.451589][ C1] do_exit+0x238f/0x2dd0 [ 62.455986][ C1] call_usermodehelper_exec_async+0x507/0x710 [ 62.462209][ C1] ret_from_fork+0x24/0x30 [ 62.467488][ C1] [ 62.470226][ C1] -> (tasklist_lock){.+.?}-{2:2} { [ 62.475940][ C1] HARDIRQ-ON-R at: [ 62.479901][ C1] lock_acquire+0x1f2/0x8f0 [ 62.486388][ C1] _raw_read_lock+0x2d/0x40 [ 62.493242][ C1] do_wait+0x3b9/0xa00 [ 62.499126][ C1] kernel_wait4+0x14c/0x260 [ 62.506221][ C1] call_usermodehelper_exec_work+0x172/0x260 [ 62.515996][ C1] process_one_work+0x965/0x16a0 [ 62.523779][ C1] worker_thread+0x96/0xe20 [ 62.530366][ C1] kthread+0x388/0x470 [ 62.536151][ C1] ret_from_fork+0x24/0x30 [ 62.542189][ C1] IN-SOFTIRQ-R at: [ 62.546154][ C1] lock_acquire+0x1f2/0x8f0 [ 62.552296][ C1] _raw_read_lock+0x2d/0x40 [ 62.558438][ C1] send_sigurg+0x9f/0x320 [ 62.564406][ C1] sk_send_sigurg+0x76/0x300 [ 62.570628][ C1] tcp_urg+0x38c/0xb80 [ 62.576327][ C1] tcp_rcv_established+0x8f3/0x1d90 [ 62.583163][ C1] tcp_v4_do_rcv+0x605/0x8b0 [ 62.589394][ C1] tcp_v4_rcv+0x2f60/0x39c0 [ 62.595543][ C1] ip_protocol_deliver_rcu+0x57/0x880 [ 62.602541][ C1] ip_local_deliver_finish+0x220/0x360 [ 62.609631][ C1] ip_local_deliver+0x1c8/0x4e0 [ 62.616287][ C1] ip_rcv_finish+0x1da/0x2f0 [ 62.622501][ C1] ip_rcv+0xd0/0x3c0 [ 62.628039][ C1] __netif_receive_skb_one_core+0xf5/0x160 [ 62.635465][ C1] __netif_receive_skb+0x27/0x1c0 [ 62.642112][ C1] process_backlog+0x21e/0x7a0 [ 62.648555][ C1] net_rx_action+0x4c2/0x1070 [ 62.655262][ C1] __do_softirq+0x26c/0x9f7 [ 62.661407][ C1] irq_exit+0x192/0x1d0 [ 62.667201][ C1] smp_apic_timer_interrupt+0x19e/0x600 [ 62.674377][ C1] apic_timer_interrupt+0xf/0x20 [ 62.680968][ C1] native_safe_halt+0xe/0x10 [ 62.687189][ C1] default_idle+0x49/0x350 [ 62.693232][ C1] do_idle+0x393/0x690 [ 62.698936][ C1] cpu_startup_entry+0x14/0x20 [ 62.705326][ C1] start_secondary+0x2f3/0x400 [ 62.711715][ C1] secondary_startup_64+0xa4/0xb0 [ 62.718369][ C1] SOFTIRQ-ON-R at: [ 62.722326][ C1] lock_acquire+0x1f2/0x8f0 [ 62.728619][ C1] _raw_read_lock+0x2d/0x40 [ 62.734753][ C1] do_wait+0x3b9/0xa00 [ 62.740497][ C1] kernel_wait4+0x14c/0x260 [ 62.746738][ C1] call_usermodehelper_exec_work+0x172/0x260 [ 62.754347][ C1] process_one_work+0x965/0x16a0 [ 62.760912][ C1] worker_thread+0x96/0xe20 [ 62.767042][ C1] kthread+0x388/0x470 [ 62.772735][ C1] ret_from_fork+0x24/0x30 [ 62.778770][ C1] INITIAL USE at: [ 62.782642][ C1] lock_acquire+0x1f2/0x8f0 [ 62.788686][ C1] _raw_write_lock_irq+0x5b/0x80 [ 62.795170][ C1] copy_process+0x3430/0x72c0 [ 62.801388][ C1] _do_fork+0x12d/0x1010 [ 62.807169][ C1] kernel_thread+0xb1/0xf0 [ 62.813136][ C1] rest_init+0x23/0x365 [ 62.818844][ C1] start_kernel+0x867/0x8a1 [ 62.824890][ C1] secondary_startup_64+0xa4/0xb0 [ 62.831468][ C1] } [ 62.833966][ C1] ... key at: [] tasklist_lock+0x18/0x40 [ 62.841648][ C1] ... acquired at: [ 62.845433][ C1] mark_lock+0x624/0xf10 [ 62.849822][ C1] __lock_acquire+0x1ed9/0x4e00 [ 62.854837][ C1] lock_acquire+0x1f2/0x8f0 [ 62.859512][ C1] _raw_read_lock+0x2d/0x40 [ 62.864217][ C1] send_sigurg+0x9f/0x320 [ 62.868725][ C1] sk_send_sigurg+0x76/0x300 [ 62.873626][ C1] tcp_urg+0x38c/0xb80 [ 62.877905][ C1] tcp_rcv_established+0x8f3/0x1d90 [ 62.883312][ C1] tcp_v4_do_rcv+0x605/0x8b0 [ 62.888051][ C1] tcp_v4_rcv+0x2f60/0x39c0 [ 62.892739][ C1] ip_protocol_deliver_rcu+0x57/0x880 [ 62.898275][ C1] ip_local_deliver_finish+0x220/0x360 [ 62.904147][ C1] ip_local_deliver+0x1c8/0x4e0 [ 62.909148][ C1] ip_rcv_finish+0x1da/0x2f0 [ 62.913886][ C1] ip_rcv+0xd0/0x3c0 [ 62.917940][ C1] __netif_receive_skb_one_core+0xf5/0x160 [ 62.923888][ C1] __netif_receive_skb+0x27/0x1c0 [ 62.929057][ C1] process_backlog+0x21e/0x7a0 [ 62.933968][ C1] net_rx_action+0x4c2/0x1070 [ 62.938803][ C1] __do_softirq+0x26c/0x9f7 [ 62.943451][ C1] irq_exit+0x192/0x1d0 [ 62.947760][ C1] smp_apic_timer_interrupt+0x19e/0x600 [ 62.953466][ C1] apic_timer_interrupt+0xf/0x20 [ 62.958558][ C1] native_safe_halt+0xe/0x10 [ 62.963296][ C1] default_idle+0x49/0x350 [ 62.967867][ C1] do_idle+0x393/0x690 [ 62.972087][ C1] cpu_startup_entry+0x14/0x20 [ 62.977011][ C1] start_secondary+0x2f3/0x400 [ 62.981922][ C1] secondary_startup_64+0xa4/0xb0 [ 62.987095][ C1] [ 62.989395][ C1] [ 62.989395][ C1] stack backtrace: [ 62.995276][ C1] CPU: 1 PID: 0 Comm: swapper/1 Not tainted 5.6.0-syzkaller #0 [ 63.002874][ C1] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 63.012915][ C1] Call Trace: [ 63.016184][ C1] [ 63.019012][ C1] dump_stack+0x188/0x20d [ 63.023357][ C1] check_usage_forwards.cold+0x20/0x29 [ 63.028807][ C1] ? check_usage_backwards+0x4e0/0x4e0 [ 63.034251][ C1] ? stack_trace_save+0x8c/0xc0 [ 63.039225][ C1] ? stack_trace_consume_entry+0x160/0x160 [ 63.045071][ C1] ? lockdep_hardirqs_on+0x196/0x620 [ 63.050336][ C1] ? __bfs+0x76/0x520 [ 63.054305][ C1] ? save_trace+0x42/0x9f0 [ 63.058851][ C1] mark_lock+0x624/0xf10 [ 63.063083][ C1] ? check_usage_backwards+0x4e0/0x4e0 [ 63.068533][ C1] ? print_usage_bug+0x240/0x240 [ 63.073446][ C1] __lock_acquire+0x1ed9/0x4e00 [ 63.078278][ C1] ? mark_held_locks+0xe0/0xe0 [ 63.083032][ C1] ? bictcp_cong_avoid+0x142/0xe80 [ 63.088151][ C1] ? tcp_rate_gen+0x456/0x6a0 [ 63.092817][ C1] ? tcp_newly_delivered+0x116/0x160 [ 63.098079][ C1] ? tcp_update_pacing_rate+0x1cf/0x2d0 [ 63.103605][ C1] lock_acquire+0x1f2/0x8f0 [ 63.108330][ C1] ? send_sigurg+0x9f/0x320 [ 63.113043][ C1] ? lock_release+0x800/0x800 [ 63.117703][ C1] _raw_read_lock+0x2d/0x40 [ 63.122196][ C1] ? send_sigurg+0x9f/0x320 [ 63.126744][ C1] send_sigurg+0x9f/0x320 [ 63.131077][ C1] sk_send_sigurg+0x76/0x300 [ 63.135650][ C1] tcp_urg+0x38c/0xb80 [ 63.139706][ C1] ? __tcp_ack_snd_check+0x950/0x950 [ 63.144964][ C1] ? tcp_validate_incoming+0x42b/0x1670 [ 63.150498][ C1] tcp_rcv_established+0x8f3/0x1d90 [ 63.155780][ C1] ? lock_release+0x800/0x800 [ 63.160441][ C1] ? tcp_data_queue+0x4430/0x4430 [ 63.165548][ C1] ? do_raw_spin_lock+0x129/0x2e0 [ 63.170572][ C1] tcp_v4_do_rcv+0x605/0x8b0 [ 63.175148][ C1] tcp_v4_rcv+0x2f60/0x39c0 [ 63.179655][ C1] ? tcp_v4_early_demux+0x8d0/0x8d0 [ 63.184908][ C1] ? rcu_read_lock_held+0x9c/0xb0 [ 63.189962][ C1] ? rcu_read_lock_held_common+0x130/0x130 [ 63.195780][ C1] ip_protocol_deliver_rcu+0x57/0x880 [ 63.201133][ C1] ip_local_deliver_finish+0x220/0x360 [ 63.206579][ C1] ip_local_deliver+0x1c8/0x4e0 [ 63.211425][ C1] ? ip_local_deliver_finish+0x360/0x360 [ 63.217030][ C1] ? ip_rcv+0x24e/0x3c0 [ 63.221173][ C1] ? ip_protocol_deliver_rcu+0x880/0x880 [ 63.226780][ C1] ? lock_downgrade+0x840/0x840 [ 63.231692][ C1] ? ip_rcv_finish_core.isra.0+0x606/0x1ec0 [ 63.237559][ C1] ip_rcv_finish+0x1da/0x2f0 [ 63.242126][ C1] ip_rcv+0xd0/0x3c0 [ 63.246018][ C1] ? ip_local_deliver+0x4e0/0x4e0 [ 63.251037][ C1] ? ip_rcv_finish_core.isra.0+0x1ec0/0x1ec0 [ 63.257017][ C1] ? lock_acquire+0x1f2/0x8f0 [ 63.263277][ C1] ? process_backlog+0x1ad/0x7a0 [ 63.268300][ C1] ? ip_local_deliver+0x4e0/0x4e0 [ 63.273327][ C1] __netif_receive_skb_one_core+0xf5/0x160 [ 63.279826][ C1] ? __netif_receive_skb_core+0x30e0/0x30e0 [ 63.285701][ C1] ? rwlock_bug.part.0+0x90/0x90 [ 63.290634][ C1] __netif_receive_skb+0x27/0x1c0 [ 63.295742][ C1] process_backlog+0x21e/0x7a0 [ 63.302016][ C1] ? rcu_read_lock_sched_held+0x9c/0xd0 [ 63.307818][ C1] ? net_rx_action+0x25f/0x1070 [ 63.314035][ C1] net_rx_action+0x4c2/0x1070 [ 63.319672][ C1] ? napi_busy_loop+0x950/0x950 [ 63.326310][ C1] ? rcu_read_lock_any_held.part.0+0x50/0x50 [ 63.333855][ C1] ? run_rebalance_domains+0x202/0x2c0 [ 63.339485][ C1] __do_softirq+0x26c/0x9f7 [ 63.344509][ C1] irq_exit+0x192/0x1d0 [ 63.348643][ C1] smp_apic_timer_interrupt+0x19e/0x600 [ 63.355323][ C1] apic_timer_interrupt+0xf/0x20 [ 63.360246][ C1] [ 63.363207][ C1] RIP: 0010:native_safe_halt+0xe/0x10 [ 63.371057][ C1] Code: cc cc cc cc cc cc cc cc cc cc cc cc e9 07 00 00 00 0f 00 2d 44 ae 5e 00 f4 c3 66 90 e9 07 00 00 00 0f 00 2d 34 ae 5e 00 fb f4 cc 41 56 41 55 41 54 55 53 e8 c3 07 97 f9 e8 9e 72 cb fb 0f 1f [ 63.391970][ C1] RSP: 0018:ffffc90000d3fdb8 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff13 [ 63.400372][ C1] RAX: 1ffffffff13291af RBX: ffff8880a95f2340 RCX: 0000000000000000 [ 63.408447][ C1] RDX: dffffc0000000000 RSI: 0000000000000006 RDI: ffff8880a95f2c04 [ 63.416831][ C1] RBP: dffffc0000000000 R08: ffff8880a95f2340 R09: 0000000000000000 [ 63.424863][ C1] R10: 0000000000000000 R11: 0000000000000000 R12: ffffed10152be468 [ 63.432826][ C1] R13: 0000000000000001 R14: ffffffff8a883540 R15: 0000000000000000 [ 63.440800][ C1] default_idle+0x49/0x350 [ 63.445200][ C1] do_idle+0x393/0x690 [ 63.449244][ C1] ? arch_cpu_idle_exit+0x70/0x70 [ 63.454498][ C1] ? _raw_spin_unlock_irqrestore+0x62/0xe0 [ 63.460285][ C1] ? lockdep_hardirqs_on+0x463/0x620 [ 63.465573][ C1] cpu_startup_entry+0x14/0x20 [ 63.470312][ C1] start_secondary+0x2f3/0x400 [ 63.475053][ C1] ? set_cpu_sibling_map+0x1ed0/0x1ed0 [ 63.480632][ C1] secondary_startup_64+0xa4/0xb0