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BUG: KCSAN: data-race in copy_mm / percpu_counter_destroy_many

write to 0xffff8881022e3468 of 8 bytes by task 7875 on cpu 1:
 __list_del include/linux/list.h:203 [inline]
 __list_del_entry include/linux/list.h:226 [inline]
 list_del include/linux/list.h:237 [inline]
 percpu_counter_destroy_many+0xc7/0x2b0 lib/percpu_counter.c:244
 __mmdrop+0x25d/0x3f0 kernel/fork.c:735
 mmdrop include/linux/sched/mm.h:55 [inline]
 mmdrop_sched include/linux/sched/mm.h:83 [inline]
 mmdrop_lazy_tlb_sched include/linux/sched/mm.h:110 [inline]
 finish_task_switch+0x184/0x280 kernel/sched/core.c:5180
 context_switch kernel/sched/core.c:5301 [inline]
 __schedule+0x93c/0xd40 kernel/sched/core.c:6911
 preempt_schedule_irq+0x2d/0x50 kernel/sched/core.c:7238
 raw_irqentry_exit_cond_resched+0x4b/0x60 kernel/entry/common.c:196
 irqentry_exit+0x91/0x520 kernel/entry/common.c:239
 sysvec_apic_timer_interrupt+0x44/0x80 arch/x86/kernel/apic/apic.c:1056
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
 prealloc_lru_pop kernel/bpf/hashtab.c:307 [inline]
 htab_lru_map_update_elem+0x10d/0x700 kernel/bpf/hashtab.c:1303
 bpf_map_update_value+0x4f3/0x570 kernel/bpf/syscall.c:297
 generic_map_update_batch+0x52d/0x680 kernel/bpf/syscall.c:2032
 bpf_map_do_batch+0x25c/0x380 kernel/bpf/syscall.c:5690
 __sys_bpf+0x6a2/0x7e0 kernel/bpf/syscall.c:-1
 __do_sys_bpf kernel/bpf/syscall.c:6362 [inline]
 __se_sys_bpf kernel/bpf/syscall.c:6360 [inline]
 __x64_sys_bpf+0x41/0x50 kernel/bpf/syscall.c:6360
 x64_sys_call+0x10cb/0x3020 arch/x86/include/generated/asm/syscalls_64.h:322
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x12c/0x370 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff8881022e2f40 of 1664 bytes by task 7892 on cpu 0:
 dup_mm kernel/fork.c:1525 [inline]
 copy_mm+0xe1/0x370 kernel/fork.c:1583
 copy_process+0xe22/0x20b0 kernel/fork.c:2223
 kernel_clone+0x16b/0x5d0 kernel/fork.c:2653
 __do_sys_clone kernel/fork.c:2794 [inline]
 __se_sys_clone kernel/fork.c:2778 [inline]
 __x64_sys_clone+0x143/0x180 kernel/fork.c:2778
 x64_sys_call+0x1222/0x3020 arch/x86/include/generated/asm/syscalls_64.h:57
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x12c/0x370 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 7892 Comm: dhcpcd-run-hook Tainted: G        W           syzkaller #0 PREEMPT(full) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
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