rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P3493/2:b..l P3531/1:b..l (detected by 1, t=10503 jiffies, g=31681, q=61) task:syz-executor.5 state:R running task stack:20696 pid: 3531 ppid: 3513 flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5030 [inline] __schedule+0x12c4/0x45b0 kernel/sched/core.c:6376 preempt_schedule_irq+0xf7/0x1c0 kernel/sched/core.c:6780 irqentry_exit+0x53/0x80 kernel/entry/common.c:426 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:638 RIP: 0010:walk_component+0x4e5/0x610 fs/namei.c:1957 Code: 00 fc ff df e9 83 fc ff ff e8 37 ba a6 ff 48 bb 00 00 00 00 00 fc ff df 4c 8b 74 24 10 e9 39 ff ff ff 48 8d 8c 24 80 00 00 00 <80> e1 07 80 c1 03 38 c1 0f 8c ce fb ff ff 48 8d bc 24 80 00 00 00 RSP: 0018:ffffc90002f176e0 EFLAGS: 00000202 RAX: 0000000000000004 RBX: dffffc0000000000 RCX: ffffc90002f17760 RDX: 0000000000000000 RSI: 0000000000000002 RDI: ffffc90002f17bc0 RBP: ffffc90002f177d0 R08: 0000000000000001 R09: ffffffff81d919a1 R10: 0000000000000002 R11: ffff88807de99dc0 R12: ffffc90002f17740 R13: 1ffff920005e2ee4 R14: ffffc90002f17bc0 R15: 1ffff920005e2eec link_path_walk+0x642/0xd90 path_openat+0x249/0x2f20 fs/namei.c:3668 do_filp_open+0x21c/0x460 fs/namei.c:3699 do_sys_openat2+0x13b/0x500 fs/open.c:1211 do_sys_open fs/open.c:1227 [inline] __do_sys_openat fs/open.c:1243 [inline] __se_sys_openat fs/open.c:1238 [inline] __x64_sys_openat+0x243/0x290 fs/open.c:1238 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x61/0xcb RIP: 0033:0x7f7178843541 RSP: 002b:00007ffc21f90200 EFLAGS: 00000287 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007f717888e3b9 RCX: 00007f7178843541 RDX: 0000000000090800 RSI: 00007ffc21f913e0 RDI: 00000000ffffff9c RBP: 00007ffc21f913bc R08: 0000000000000000 R09: 0000000000000010 R10: 0000000000000000 R11: 0000000000000287 R12: 00007ffc21f913e0 R13: 00007f717888e3b9 R14: 000000000006b721 R15: 0000000000000002 task:sshd state:R running task stack:22624 pid: 3493 ppid: 3265 flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5030 [inline] __schedule+0x12c4/0x45b0 kernel/sched/core.c:6376 preempt_schedule_irq+0xf7/0x1c0 kernel/sched/core.c:6780 irqentry_exit+0x53/0x80 kernel/entry/common.c:426 asm_sysvec_reschedule_ipi+0x16/0x20 arch/x86/include/asm/idtentry.h:643 RIP: 0010:lock_is_held_type+0x137/0x180 Code: 75 40 48 c7 04 24 00 00 00 00 9c 8f 04 24 f7 04 24 00 02 00 00 75 46 41 f7 c4 00 02 00 00 74 01 fb 65 48 8b 04 25 28 00 00 00 <48> 3b 44 24 08 75 3c 89 e8 48 83 c4 10 5b 41 5c 41 5d 41 5e 41 5f RSP: 0018:ffffc900012df158 EFLAGS: 00000206 RAX: 8a455fd942e40500 RBX: 0000000000000001 RCX: 0000000080000000 RDX: ffff88807c8cbb80 RSI: ffffffff8a8b2000 RDI: ffffffff8ad87d40 RBP: 0000000000000001 R08: ffffffff88b95983 R09: fffffbfff1f79c19 R10: 0000000000000000 R11: dffffc0000000001 R12: 0000000000000246 R13: ffff88807c8cbb80 R14: 00000000ffffffff R15: ffffffff8c91f0e0 nf_hook+0x15c/0x430 include/linux/netfilter.h:229 __ip_local_out+0x3b2/0x4f0 net/ipv4/ip_output.c:115 ip_local_out net/ipv4/ip_output.c:124 [inline] __ip_queue_xmit+0x11d9/0x1ce0 net/ipv4/ip_output.c:532 __tcp_transmit_skb+0x1f39/0x3810 net/ipv4/tcp_output.c:1402 tcp_transmit_skb net/ipv4/tcp_output.c:1420 [inline] tcp_write_xmit+0x19e5/0x65f0 net/ipv4/tcp_output.c:2705 __tcp_push_pending_frames+0x90/0x250 net/ipv4/tcp_output.c:2890 tcp_sendmsg_locked+0x315c/0x3a90 net/ipv4/tcp.c:1427 tcp_sendmsg+0x2c/0x40 net/ipv4/tcp.c:1455 sock_sendmsg_nosec net/socket.c:704 [inline] __sock_sendmsg net/socket.c:716 [inline] sock_write_iter+0x39b/0x530 net/socket.c:1077 call_write_iter include/linux/fs.h:2103 [inline] new_sync_write fs/read_write.c:507 [inline] vfs_write+0xacf/0xe50 fs/read_write.c:594 ksys_write+0x1a2/0x2c0 fs/read_write.c:647 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x61/0xcb RIP: 0033:0x7f6098e80bf2 RSP: 002b:00007ffc3308bfe8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00000000000000bc RCX: 00007f6098e80bf2 RDX: 00000000000000bc RSI: 000055823979df20 RDI: 0000000000000004 RBP: 0000558239774de0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000558238fb9aa4 R13: 00000000000001b8 R14: 0000558238fba3e8 R15: 00007ffc3308c058 rcu: rcu_preempt kthread starved for 10565 jiffies! g31681 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1 rcu: Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior. rcu: RCU grace-period kthread stack dump: task:rcu_preempt state:R running task stack:27000 pid: 15 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5030 [inline] __schedule+0x12c4/0x45b0 kernel/sched/core.c:6376 schedule+0x11b/0x1f0 kernel/sched/core.c:6459 schedule_timeout+0x1b9/0x300 kernel/time/timer.c:1884 rcu_gp_fqs_loop+0x2bf/0x1080 kernel/rcu/tree.c:1972 rcu_gp_kthread+0xa4/0x360 kernel/rcu/tree.c:2145 kthread+0x3f6/0x4f0 kernel/kthread.c:319 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298 rcu: Stack dump where RCU GP kthread last ran: NMI backtrace for cpu 1 CPU: 1 PID: 8568 Comm: syz-executor.2 Not tainted 5.15.141-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/10/2023 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106 nmi_cpu_backtrace+0x46a/0x4a0 lib/nmi_backtrace.c:111 nmi_trigger_cpumask_backtrace+0x181/0x2a0 lib/nmi_backtrace.c:62 trigger_single_cpu_backtrace include/linux/nmi.h:166 [inline] rcu_check_gp_kthread_starvation+0x1d2/0x240 kernel/rcu/tree_stall.h:487 print_other_cpu_stall+0x137a/0x14d0 kernel/rcu/tree_stall.h:592 check_cpu_stall kernel/rcu/tree_stall.h:745 [inline] rcu_pending kernel/rcu/tree.c:3932 [inline] rcu_sched_clock_irq+0xa38/0x1150 kernel/rcu/tree.c:2619 update_process_times+0x196/0x200 kernel/time/timer.c:1788 tick_sched_handle kernel/time/tick-sched.c:254 [inline] tick_sched_timer+0x386/0x550 kernel/time/tick-sched.c:1473 __run_hrtimer kernel/time/hrtimer.c:1685 [inline] __hrtimer_run_queues+0x55b/0xcf0 kernel/time/hrtimer.c:1749 hrtimer_interrupt+0x392/0x980 kernel/time/hrtimer.c:1811 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1085 [inline] __sysvec_apic_timer_interrupt+0x139/0x470 arch/x86/kernel/apic/apic.c:1102 sysvec_apic_timer_interrupt+0x8c/0xb0 arch/x86/kernel/apic/apic.c:1096 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:638 RIP: 0010:lock_is_held_type+0x137/0x180 Code: 75 40 48 c7 04 24 00 00 00 00 9c 8f 04 24 f7 04 24 00 02 00 00 75 46 41 f7 c4 00 02 00 00 74 01 fb 65 48 8b 04 25 28 00 00 00 <48> 3b 44 24 08 75 3c 89 e8 48 83 c4 10 5b 41 5c 41 5d 41 5e 41 5f RSP: 0018:ffffc900053c79b8 EFLAGS: 00000206 RAX: c4e0f92ff5deb300 RBX: ffff888056b01dc0 RCX: ffff888056b01dc0 RDX: 0000000000000000 RSI: ffffffff8a8b2000 RDI: ffffffff8ad87d40 RBP: 0000000000000000 R08: ffffffff81b96e8c R09: ffffc900053c7c00 R10: 0000000000000000 R11: dffffc0000000001 R12: 0000000000000246 R13: ffff888056b01dc0 R14: 00000000ffffffff R15: ffffffff8c91f140 lock_is_held include/linux/lockdep.h:287 [inline] ___might_sleep+0xa2/0x6a0 kernel/sched/core.c:9592 __might_fault+0x6b/0x110 mm/memory.c:5321 clear_rseq_cs kernel/rseq.c:220 [inline] rseq_ip_fixup kernel/rseq.c:254 [inline] __rseq_handle_notify_resume+0x5de/0x1250 kernel/rseq.c:292 rseq_handle_notify_resume include/linux/sched.h:2208 [inline] rseq_signal_deliver include/linux/sched.h:2217 [inline] setup_rt_frame arch/x86/kernel/signal.c:769 [inline] handle_signal arch/x86/kernel/signal.c:824 [inline] arch_do_signal_or_restart+0x27d/0x1890 arch/x86/kernel/signal.c:869 handle_signal_work kernel/entry/common.c:148 [inline] exit_to_user_mode_loop+0x97/0x130 kernel/entry/common.c:172 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:208 __syscall_exit_to_user_mode_work kernel/entry/common.c:290 [inline] syscall_exit_to_user_mode+0x5d/0x250 kernel/entry/common.c:301 do_syscall_64+0x49/0xb0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x61/0xcb RIP: 0033:0x7fc4005b75e7 Code: 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 b8 02 01 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fc3fead6ee8 EFLAGS: 00000213 RAX: 0000000000000000 RBX: 00000000200005c0 RCX: 00007fc4005b75e7 RDX: 00000000000001ff RSI: 0000000020000000 RDI: 00000000ffffff9c RBP: 0000000020000440 R08: 0000000000000000 R09: 0000000000000235 R10: 0000000000000000 R11: 0000000000000213 R12: 0000000020000000 R13: 00007fc3fead6f40 R14: 000000000000023b R15: 0000000020000480