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BUG: KCSAN: data-race in __anon_vma_prepare / handle_mm_fault

write to 0xffff88811c31b700 of 8 bytes by task 17788 on cpu 0:
 __anon_vma_prepare+0x172/0x2f0 mm/rmap.c:212
 __vmf_anon_prepare mm/memory.c:3829 [inline]
 vmf_anon_prepare mm/internal.h:494 [inline]
 do_anonymous_page mm/memory.c:5338 [inline]
 do_pte_missing mm/memory.c:4564 [inline]
 handle_pte_fault mm/memory.c:6379 [inline]
 __handle_mm_fault mm/memory.c:6517 [inline]
 handle_mm_fault+0x2405/0x2da0 mm/memory.c:6686
 do_user_addr_fault+0x402/0x1060 arch/x86/mm/fault.c:1394
 handle_page_fault arch/x86/mm/fault.c:1483 [inline]
 exc_page_fault+0x62/0xa0 arch/x86/mm/fault.c:1536
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:595
 __put_user_4+0xd/0x30 arch/x86/lib/putuser.S:92
 __sys_socketpair+0xa6/0x430 net/socket.c:1843
 __do_sys_socketpair net/socket.c:1909 [inline]
 __se_sys_socketpair net/socket.c:1906 [inline]
 __x64_sys_socketpair+0x52/0x60 net/socket.c:1906
 x64_sys_call+0x2de5/0x3020 arch/x86/include/generated/asm/syscalls_64.h:54
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x136/0x3c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff88811c31b700 of 8 bytes by task 17787 on cpu 1:
 __vmf_anon_prepare mm/memory.c:3823 [inline]
 vmf_anon_prepare mm/internal.h:494 [inline]
 do_anonymous_page mm/memory.c:5338 [inline]
 do_pte_missing mm/memory.c:4564 [inline]
 handle_pte_fault mm/memory.c:6379 [inline]
 __handle_mm_fault mm/memory.c:6517 [inline]
 handle_mm_fault+0xfdf/0x2da0 mm/memory.c:6686
 do_user_addr_fault+0x634/0x1060 arch/x86/mm/fault.c:1343
 handle_page_fault arch/x86/mm/fault.c:1483 [inline]
 exc_page_fault+0x62/0xa0 arch/x86/mm/fault.c:1536
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:595

value changed: 0x0000000000000000 -> 0xffff888104f08300

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 17787 Comm: syz.3.13285 Tainted: G        W           syzkaller #0 PREEMPT(lazy) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
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