rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-....: (1 GPs behind) idle=125/1/0x4000000000000000 softirq=6801/6802 fqs=2100 (detected by 1, t=10506 jiffies, g=8445, q=212) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 1483 Comm: kworker/u4:4 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 Workqueue: netns cleanup_net RIP: 0010:instrument_atomic_write include/linux/instrumented.h:86 [inline] RIP: 0010:llist_add_batch+0x5f/0xa0 lib/llist.c:33 Code: 74 08 48 89 df e8 01 4e e2 fd 4c 8b 23 48 b8 00 00 00 00 00 fc ff df 41 80 7c 05 00 00 74 08 4c 89 f7 e8 64 4e e2 fd 4d 89 26 <48> 89 df be 08 00 00 00 e8 74 4f e2 fd 4c 89 e0 f0 4c 0f b1 3b 4c RSP: 0018:ffffc90000006f80 EFLAGS: 00000046 RAX: dffffc0000000000 RBX: ffff8880b9033d70 RCX: ffff888023531dc0 RDX: 0000000000000100 RSI: ffff8880b903b1f0 RDI: ffff8880b903b1f0 RBP: 1ffff110172067ae R08: dffffc0000000000 R09: ffffed1017207640 R10: ffffed1017207640 R11: 1ffff1101720763f R12: 0000000000000000 R13: 1ffff1101720763e R14: ffff8880b903b1f0 R15: ffff8880b903b1f0 FS: 0000000000000000(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055558063a808 CR3: 000000001e4fa000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: llist_add include/linux/llist.h:219 [inline] __irq_work_queue_local+0xad/0x190 kernel/irq_work.c:61 irq_work_queue_on+0x11e/0x220 kernel/irq_work.c:109 rcu_read_unlock_special+0x379/0x480 kernel/rcu/tree_plugin.h:667 __rcu_read_unlock+0x78/0xd0 kernel/rcu/tree_plugin.h:422 rcu_read_unlock include/linux/rcupdate.h:772 [inline] __perf_event_output kernel/events/core.c:7813 [inline] perf_event_output_forward+0x216/0x280 kernel/events/core.c:7822 __perf_event_overflow+0x364/0x530 kernel/events/core.c:9515 perf_tp_event+0x32c/0xb50 kernel/events/core.c:10047 perf_trace_run_bpf_submit+0xf3/0x1c0 kernel/events/core.c:10021 perf_trace_preemptirq_template+0x2be/0x380 include/trace/events/preemptirq.h:14 trace_irq_enable_rcuidle+0x108/0x180 include/trace/events/preemptirq.h:40 trace_hardirqs_on+0x57/0x80 kernel/trace/trace_preemptirq.c:44 asm_sysvec_irq_work+0x16/0x20 arch/x86/include/asm/idtentry.h:713 RIP: 0010:rcu_read_unlock_special+0x84/0x480 kernel/rcu/tree_plugin.h:674 Code: f1 f1 f1 00 f2 f2 f2 4a 89 04 2b 66 42 c7 44 2b 09 f3 f3 42 c6 44 2b 0b f3 65 44 8b 35 ed 11 9e 7e 41 f7 c6 00 00 f0 00 74 45 <48> c7 44 24 20 0e 36 e0 45 4a c7 04 2b 00 00 00 00 66 42 c7 44 2b RSP: 0018:ffffc90000007780 EFLAGS: 00000206 RAX: fb510eca6889f800 RBX: 1ffff92000000ef4 RCX: fb510eca6889f800 RDX: dffffc0000000000 RSI: ffffffff8a0b1be0 RDI: ffffffff8a59e800 RBP: ffffc90000007860 R08: dffffc0000000000 R09: fffffbfff1ff542c R10: fffffbfff1ff542c R11: 1ffffffff1ff542b R12: ffffffff8c120c00 R13: dffffc0000000000 R14: 0000000000000246 R15: 0000000000000001 __rcu_read_unlock+0x78/0xd0 kernel/rcu/tree_plugin.h:422 rcu_read_unlock include/linux/rcupdate.h:772 [inline] __ip_queue_xmit+0x1244/0x1c00 net/ipv4/ip_output.c:533 __tcp_transmit_skb+0x1ced/0x31c0 net/ipv4/tcp_output.c:1404 tcp_delack_timer_handler+0x32e/0x730 net/ipv4/tcp_timer.c:314 tcp_delack_timer+0x188/0x2e0 net/ipv4/tcp_timer.c:341 call_timer_fn+0x16c/0x530 kernel/time/timer.c:1451 expire_timers kernel/time/timer.c:1496 [inline] __run_timers+0x525/0x7c0 kernel/time/timer.c:1767 run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1780 handle_softirqs+0x328/0x820 kernel/softirq.c:576 __do_softirq kernel/softirq.c:610 [inline] invoke_softirq kernel/softirq.c:450 [inline] __irq_exit_rcu+0x12f/0x220 kernel/softirq.c:659 irq_exit_rcu+0x5/0x20 kernel/softirq.c:671 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline] sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1108 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676 RIP: 0010:lock_is_held_type+0x13a/0x190 kernel/locking/lockdep.c:5671 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 c5 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:ffffc900061178d8 EFLAGS: 00000206 RAX: fb510eca6889f800 RBX: ffff888023531dc0 RCX: fb510eca6889f800 RDX: 0000000000000000 RSI: ffffffff8a0b2e80 RDI: ffffffff8a59e800 RBP: 0000000000000000 R08: dffffc0000000000 R09: fffffbfff1ad26b6 R10: fffffbfff1ad26b6 R11: 1ffffffff1ad26b5 R12: 0000000000000003 R13: 0000000000000246 R14: ffffffff8c11c7e0 R15: ffff888023532928 lock_is_held include/linux/lockdep.h:287 [inline] ___might_sleep+0xf2/0x600 kernel/sched/core.c:9624 inet_twsk_purge+0x10a/0x810 net/ipv4/inet_timewait_sock.c:267 ops_exit_list net/core/net_namespace.c:177 [inline] cleanup_net+0x77b/0xb80 net/core/net_namespace.c:635 process_one_work+0x863/0x1000 kernel/workqueue.c:2310 worker_thread+0xaa8/0x12a0 kernel/workqueue.c:2457 kthread+0x436/0x520 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287