rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P144/1:b..l (detected by 1, t=10503 jiffies, g=8025, q=375) task:kworker/u4:1 state:R running task stack:21080 pid: 144 ppid: 2 flags:0x00004000 Workqueue: netns cleanup_net Call Trace: context_switch kernel/sched/core.c:5049 [inline] __schedule+0x11ef/0x43c0 kernel/sched/core.c:6395 preempt_schedule_irq+0xbb/0x160 kernel/sched/core.c:6799 irqentry_exit+0x63/0x70 kernel/entry/common.c:432 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676 RIP: 0010:preempt_count arch/x86/include/asm/preempt.h:27 [inline] RIP: 0010:check_kcov_mode kernel/kcov.c:172 [inline] RIP: 0010:__sanitizer_cov_trace_pc+0xc/0x60 kernel/kcov.c:206 Code: 89 fb e8 17 00 00 00 48 8b 3d 20 bb 10 0c 48 89 de 5b e9 37 42 44 00 00 00 cc cc 00 00 cc 48 8b 04 24 65 48 8b 0d 74 4d 89 7e <65> 8b 15 75 4d 89 7e 81 e2 00 01 ff 00 74 11 81 fa 00 01 00 00 75 RSP: 0018:ffffc900010afa30 EFLAGS: 00000293 RAX: ffffffff886377fa RBX: ffffffff966b6440 RCX: ffff88801938bb80 RDX: 0000000000000000 RSI: ffffffff8a2b3a20 RDI: ffffffff8a79f740 RBP: ffffc900010afb50 R08: ffffffff8d89db2f R09: 1ffffffff1b13b65 R10: dffffc0000000000 R11: fffffbfff1b13b66 R12: 000000000000e355 R13: dffffc0000000000 R14: ffffc9000197cab0 R15: 0000000000000001 rcu_lock_acquire+0xa/0x30 include/linux/rcupdate.h:313 rcu_read_lock include/linux/rcupdate.h:740 [inline] inet_twsk_purge+0x119/0x840 net/ipv4/inet_timewait_sock.c:268 ops_exit_list net/core/net_namespace.c:177 [inline] cleanup_net+0x791/0xba0 net/core/net_namespace.c:635 process_one_work+0x85f/0x1010 kernel/workqueue.c:2310 worker_thread+0xaa6/0x1290 kernel/workqueue.c:2457 kthread+0x436/0x520 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 rcu: rcu_preempt kthread starved for 10530 jiffies! g8025 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0 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:27416 pid: 15 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5049 [inline] __schedule+0x11ef/0x43c0 kernel/sched/core.c:6395 schedule+0x11b/0x1e0 kernel/sched/core.c:6478 schedule_timeout+0x184/0x2d0 kernel/time/timer.c:2117 rcu_gp_fqs_loop+0x2be/0x11d0 kernel/rcu/tree.c:1972 rcu_gp_kthread+0x9b/0x370 kernel/rcu/tree.c:2145 kthread+0x436/0x520 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 rcu: Stack dump where RCU GP kthread last ran: Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 4420 Comm: syz.2.23 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026 RIP: 0010:arch_static_branch arch/x86/include/asm/jump_label.h:27 [inline] RIP: 0010:static_key_false include/linux/jump_label.h:212 [inline] RIP: 0010:native_write_msr arch/x86/include/asm/msr.h:156 [inline] RIP: 0010:wrmsr arch/x86/include/asm/msr.h:263 [inline] RIP: 0010:native_apic_msr_write+0x35/0x50 arch/x86/include/asm/apic.h:208 Code: 74 2a 83 ff 30 74 25 eb 10 81 ff d0 00 00 00 74 1b 81 ff e0 00 00 00 74 13 c1 ef 04 81 c7 00 08 00 00 89 f9 89 f0 31 d2 0f 30 <66> 90 c3 89 f6 31 d2 e9 af 45 d0 02 66 2e 0f 1f 84 00 00 00 00 00 RSP: 0018:ffffc90000007e48 EFLAGS: 00000046 RAX: 0000000000053017 RBX: 0000000000053017 RCX: 0000000000000838 RDX: 0000000000000000 RSI: 0000000000053017 RDI: 0000000000000838 RBP: 0000000000000000 R08: ffffffff8d89db2f R09: 1ffffffff1b13b65 R10: dffffc0000000000 R11: fffffbfff1b13b66 R12: dffffc0000000000 R13: 0000000010005590 R14: ffffffff8be309d8 R15: dffffc0000000000 FS: 000055556630e500(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000200000000058 CR3: 0000000074d80000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: apic_write arch/x86/include/asm/apic.h:395 [inline] lapic_next_event+0x5b/0x70 arch/x86/kernel/apic/apic.c:468 clockevents_program_event+0x1bc/0x310 kernel/time/clockevents.c:334 hrtimer_interrupt+0x4de/0x8d0 kernel/time/hrtimer.c:1824 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1097 [inline] __sysvec_apic_timer_interrupt+0x137/0x4a0 arch/x86/kernel/apic/apic.c:1114 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline] sysvec_apic_timer_interrupt+0x9b/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_acquire+0x208/0x400 kernel/locking/lockdep.c:5627 Code: f7 84 24 80 00 00 00 00 02 00 00 43 c6 44 3d 04 f8 0f 85 f1 00 00 00 41 f7 c6 00 02 00 00 74 01 fb 48 c7 44 24 60 0e 36 e0 45 <4b> c7 44 3d 00 00 00 00 00 43 c7 44 3d 08 00 00 00 00 65 48 8b 04 RSP: 0018:ffffc9000379fb20 EFLAGS: 00000206 RAX: 0000000000000001 RBX: 0000000000000000 RCX: 7982392c8ef9e400 RDX: 0000000000000000 RSI: ffffffff8a2b3a20 RDI: ffffffff8a79f740 RBP: ffffc9000379fc28 R08: dffffc0000000000 R09: 1ffffffff203a41e R10: dffffc0000000000 R11: fffffbfff203a41f R12: ffff88807aa1f828 R13: 1ffff920006f3f70 R14: 0000000000000246 R15: dffffc0000000000 __might_fault+0xb3/0x110 mm/memory.c:5357 __clear_user arch/x86/lib/usercopy_64.c:20 [inline] clear_user+0xd2/0x150 arch/x86/lib/usercopy_64.c:54 copy_siginfo_to_user+0x57/0x80 kernel/signal.c:3369 __setup_rt_frame arch/x86/kernel/signal.c:490 [inline] setup_rt_frame arch/x86/kernel/signal.c:780 [inline] handle_signal arch/x86/kernel/signal.c:824 [inline] arch_do_signal_or_restart+0xd42/0x12c0 arch/x86/kernel/signal.c:869 handle_signal_work kernel/entry/common.c:154 [inline] exit_to_user_mode_loop+0x9e/0x130 kernel/entry/common.c:178 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:214 __syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline] syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:307 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7f2224bb1d27 Code: 48 8d 35 2d d9 1d 00 48 8d 3d 2e d9 1d 00 31 c0 e8 be d0 ff ff 66 0f 1f 44 00 00 41 83 fb 09 75 06 41 80 f9 01 77 d6 48 89 07 <4c> 89 d0 49 d1 ea 5b 83 e0 01 48 f7 d8 4c 31 d0 c3 48 89 c2 48 89 RSP: 002b:00007ffc296e0550 EFLAGS: 00000293 RAX: 0000001b335200df RBX: 0000001b33520000 RCX: 0000000000000000 RDX: 0000001b335200de RSI: 0000000000000001 RDI: 00007f2224f72fb0 RBP: 00007f2224f72fb0 R08: 0000001b33920000 R09: 0000000000000001 R10: 0000000000000001 R11: 0000000000000000 R12: 00007f2224f72fa0 R13: 0000200000000000 R14: 00007ffc296e0568 R15: 00007f2224f72fa0