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BUG: KCSAN: data-race in copy_mm / percpu_counter_destroy_many

write to 0xffff888118abc1e8 of 8 bytes by task 6192 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+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
 should_watch kernel/kcsan/core.c:280 [inline]
 check_access kernel/kcsan/core.c:752 [inline]
 __tsan_read8+0x117/0x190 kernel/kcsan/core.c:1025
 skb_end_pointer include/linux/skbuff.h:1724 [inline]
 __skb_datagram_iter+0x159/0x680 net/core/datagram.c:415
 skb_copy_datagram_iter+0x3f/0x120 net/core/datagram.c:535
 skb_copy_datagram_msg include/linux/skbuff.h:4218 [inline]
 __unix_dgram_recvmsg+0x4b0/0x870 net/unix/af_unix.c:2615
 unix_dgram_recvmsg net/unix/af_unix.c:2672 [inline]
 unix_seqpacket_recvmsg+0xaf/0xc0 net/unix/af_unix.c:2539
 sock_recvmsg_nosec+0xc2/0xf0 net/socket.c:1078
 ____sys_recvmsg+0x26f/0x280 net/socket.c:2810
 ___sys_recvmsg+0x11f/0x3b0 net/socket.c:2854
 do_recvmmsg+0x1ef/0x560 net/socket.c:2949
 __sys_recvmmsg net/socket.c:3023 [inline]
 __do_sys_recvmmsg net/socket.c:3046 [inline]
 __se_sys_recvmmsg net/socket.c:3039 [inline]
 __x64_sys_recvmmsg+0xe5/0x170 net/socket.c:3039
 x64_sys_call+0x80f/0x3020 arch/x86/include/generated/asm/syscalls_64.h:300
 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 0xffff888118abbcc0 of 1664 bytes by task 6246 on cpu 1:
 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: 1 UID: 0 PID: 6246 Comm: dhcpcd-run-hook Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
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