rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P14791/1:b..l P5766/1:b..l
	(detected by 0, t=10502 jiffies, g=46873, q=197)
task:kworker/u4:23   state:R  running task     stack:20792 pid: 5766 ppid:     2 flags:0x00004000
Workqueue: netns cleanup_net
Call Trace:
 <TASK>
 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:432
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:debug_lockdep_rcu_enabled+0x12/0x30 kernel/rcu/update.c:280
Code: 3c ab 8a e8 60 cc 0c f7 0f 0b eb d0 00 00 cc cc 00 00 cc cc 00 00 cc cc 31 c0 83 3d fb 71 cb 03 00 74 1d 83 3d 82 a4 cb 03 00 <74> 14 65 48 8b 0d e4 3a c3 75 31 c0 83 b9 ec 0a 00 00 00 0f 94 c0
RSP: 0018:ffffc9000324fa18 EFLAGS: 00000202
RAX: 0000000000000000 RBX: 0000000000008174 RCX: ffff8880218c5940
RDX: 0000000000000000 RSI: 0000000000008174 RDI: 0000000000008174
RBP: ffffc9000324fb30 R08: ffffffff88de3595 R09: fffffbfff2131819
R10: 0000000000000000 R11: dffffc0000000001 R12: 1ffff92000649f5a
R13: 0000000000008174 R14: dffffc0000000000 R15: ffffc9000191bba0
 rcu_read_unlock include/linux/rcupdate.h:768 [inline]
 inet_twsk_purge+0x8ab/0x9e0 net/ipv4/inet_timewait_sock.c:309
 tcp_sk_exit_batch+0x28/0x90 net/ipv4/tcp_ipv4.c:3234
 ops_exit_list net/core/net_namespace.c:177 [inline]
 cleanup_net+0x886/0xc90 net/core/net_namespace.c:618
 process_one_work+0x8a1/0x10c0 kernel/workqueue.c:2310
 worker_thread+0xaca/0x1280 kernel/workqueue.c:2457
 kthread+0x3f6/0x4f0 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>
task:cmp             state:R  running task     stack:26776 pid:14791 ppid: 14759 flags:0x00004002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5030 [inline]
 __schedule+0x12c4/0x45b0 kernel/sched/core.c:6376
 preempt_schedule_common+0x83/0xd0 kernel/sched/core.c:6552
 preempt_schedule+0xd9/0xe0 kernel/sched/core.c:6577
 preempt_schedule_thunk+0x16/0x18 arch/x86/entry/thunk_64.S:34
 __raw_spin_unlock include/linux/spinlock_api_smp.h:152 [inline]
 _raw_spin_unlock+0x36/0x40 kernel/locking/spinlock.c:186
 spin_unlock include/linux/spinlock.h:403 [inline]
 filemap_map_pages+0x122d/0x15c0 mm/filemap.c:3353
 do_fault_around mm/memory.c:4243 [inline]
 do_read_fault mm/memory.c:4258 [inline]
 do_fault mm/memory.c:4392 [inline]
 handle_pte_fault mm/memory.c:4650 [inline]
 __handle_mm_fault mm/memory.c:4785 [inline]
 handle_mm_fault+0x341b/0x5960 mm/memory.c:4883
 do_user_addr_fault arch/x86/mm/fault.c:1357 [inline]
 handle_page_fault arch/x86/mm/fault.c:1445 [inline]
 exc_page_fault+0x271/0x700 arch/x86/mm/fault.c:1501
 asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:606
RIP: 0033:0x7f14c1c6c6d6
RSP: 002b:00007ffd84fb5e28 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 00007ffd84fb5fb8 RCX: 0000000000000000
RDX: 00007ffd84fb5e64 RSI: 00007f14c1c9d224 RDI: 00007ffd84fb5fb8
RBP: 0000000000000004 R08: 00007f14c1bd3d30 R09: 00007f14c1caab5d
R10: 000000000000004f R11: 0000000000000246 R12: 00007ffd84fb5fb8
R13: 00007ffd84fb5fe0 R14: 00005611796c1169 R15: 00007f14c1cd4a80
 </TASK>
rcu: rcu_preempt kthread starved for 9739 jiffies! g46873 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:26752 pid:   15 ppid:     2 flags:0x00004000
Call Trace:
 <TASK>
 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:1914
 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:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
NMI backtrace for cpu 0
CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.15.180-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e3/0x2d0 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:1818
 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:1690 [inline]
 __hrtimer_run_queues+0x55b/0xcf0 kernel/time/hrtimer.c:1754
 hrtimer_interrupt+0x392/0x980 kernel/time/hrtimer.c:1816
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1097 [inline]
 __sysvec_apic_timer_interrupt+0x13b/0x4b0 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
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:default_idle+0xb/0x10 arch/x86/kernel/process.c:723
Code: 07 80 c1 03 38 c1 7c b5 4c 89 e7 e8 af 84 81 f7 eb ab e8 88 80 f6 ff 00 00 cc cc 00 00 cc cc 66 90 0f 00 2d 07 1b 5d 00 fb f4 <c3> 0f 1f 40 00 41 57 41 56 53 49 be 00 00 00 00 00 fc ff df 65 48
RSP: 0018:ffffffff8c807da8 EFLAGS: 000002c2
RAX: 8d8e7f1f123df200 RBX: ffffffff8c8bd680 RCX: 000000000018272c
RDX: 0000000000000001 RSI: ffffffff8aab18e0 RDI: ffffffff8af9e940
RBP: ffffffff8c807ef8 R08: dffffc0000000000 R09: ffffed10171c765a
R10: 0000000000000000 R11: dffffc0000000001 R12: 1ffffffff1900fce
R13: 1ffffffff1917ad0 R14: 0000000000000000 R15: dffffc0000000000
 default_idle_call+0x81/0xc0 kernel/sched/idle.c:112
 cpuidle_idle_call kernel/sched/idle.c:194 [inline]
 do_idle+0x271/0x670 kernel/sched/idle.c:306
 cpu_startup_entry+0x14/0x20 kernel/sched/idle.c:403
 start_kernel+0x48c/0x540 init/main.c:1140
 secondary_startup_64_no_verify+0xb1/0xbb
 </TASK>