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BUG: KCSAN: data-race in copy_mm / percpu_counter_destroy_many

write to 0xffff88811beca6c8 of 8 bytes by task 20304 on cpu 0:
 __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+0x259/0x3f0 kernel/fork.c:734
 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+0x180/0x280 kernel/sched/core.c:5143
 context_switch kernel/sched/core.c:5263 [inline]
 __schedule+0x82d/0xc90 kernel/sched/core.c:6867
 preempt_schedule_common kernel/sched/core.c:7051 [inline]
 __cond_resched+0x31/0x60 kernel/sched/core.c:7378
 might_resched include/linux/kernel.h:61 [inline]
 dput+0x17/0x60 fs/dcache.c:922
 path_put fs/namei.c:665 [inline]
 terminate_walk+0x77/0x210 fs/namei.c:792
 path_openat+0x1e4c/0x23c0 fs/namei.c:4797
 do_filp_open+0x15d/0x280 fs/namei.c:4823
 do_sys_openat2+0xa6/0x150 fs/open.c:1430
 do_sys_open fs/open.c:1436 [inline]
 __do_sys_openat fs/open.c:1452 [inline]
 __se_sys_openat fs/open.c:1447 [inline]
 __x64_sys_openat+0xf2/0x120 fs/open.c:1447
 x64_sys_call+0x2b07/0x3000 arch/x86/include/generated/asm/syscalls_64.h:258
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xc0/0x2a0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff88811beca1c0 of 1664 bytes by task 23940 on cpu 1:
 dup_mm kernel/fork.c:1523 [inline]
 copy_mm+0xe1/0x370 kernel/fork.c:1581
 copy_process+0xcbd/0x1f10 kernel/fork.c:2221
 kernel_clone+0x16b/0x5b0 kernel/fork.c:2651
 __do_sys_clone kernel/fork.c:2792 [inline]
 __se_sys_clone kernel/fork.c:2776 [inline]
 __x64_sys_clone+0x143/0x180 kernel/fork.c:2776
 x64_sys_call+0x12d0/0x3000 arch/x86/include/generated/asm/syscalls_64.h:57
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xc0/0x2a0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 23940 Comm: dhcpcd-run-hook Tainted: G        W           syzkaller #0 PREEMPT(voluntary) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
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