[moderation] [mm?] KCSAN: data-race in __anon_vma_prepare / do_wp_page (3)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 917719c412c4 Merge tag 'selinux-pr-20260507' of git://git...
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=11cc7b26580000
kernel config: https://syzkaller.appspot.com/x/.config?x=2e40c0f41e01837e
dashboard link: https://syzkaller.appspot.com/bug?extid=3180991b67b73e5f4010
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
CC: [ak...@linux-foundation.org da...@kernel.org ha...@kernel.org ja...@google.com li...@infradead.org linux-...@vger.kernel.org linu...@kvack.org l...@kernel.org ri...@surriel.com vba...@kernel.org]

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/e55e13d50f45/disk-917719c4.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/867492a186ba/vmlinux-917719c4.xz
kernel image: https://storage.googleapis.com/syzbot-assets/61eb606c9dc6/bzImage-917719c4.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+318099...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in __anon_vma_prepare / do_wp_page

write to 0xffff888133dbf040 of 8 bytes by task 14997 on cpu 0:
__anon_vma_prepare+0x172/0x2f0 mm/rmap.c:212
__vmf_anon_prepare mm/memory.c:3813 [inline]
vmf_anon_prepare mm/internal.h:503 [inline]
do_anonymous_page mm/memory.c:5372 [inline]
do_pte_missing mm/memory.c:4548 [inline]
handle_pte_fault mm/memory.c:6411 [inline]
__handle_mm_fault mm/memory.c:6549 [inline]
handle_mm_fault+0x24ae/0x2e70 mm/memory.c:6718
faultin_page mm/gup.c:1126 [inline]
__get_user_pages+0x1290/0x1f10 mm/gup.c:1428
populate_vma_page_range mm/gup.c:1860 [inline]
__mm_populate+0x242/0x390 mm/gup.c:1963
mm_populate include/linux/mm.h:4137 [inline]
vm_mmap_pgoff+0x23b/0x2d0 mm/util.c:586
ksys_mmap_pgoff+0xc1/0x310 mm/mmap.c:606
x64_sys_call+0x14df/0x3020 arch/x86/include/generated/asm/syscalls_64.h:10
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x12c/0x3b0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff888133dbf040 of 8 bytes by task 14993 on cpu 1:
__vmf_anon_prepare mm/memory.c:3807 [inline]
vmf_anon_prepare mm/internal.h:503 [inline]
wp_page_copy mm/memory.c:3854 [inline]
do_wp_page+0x65c/0x2040 mm/memory.c:4320
handle_pte_fault mm/memory.c:6427 [inline]
__handle_mm_fault mm/memory.c:6549 [inline]
handle_mm_fault+0x8b9/0x2e70 mm/memory.c:6718
do_user_addr_fault+0x3fd/0x1050 arch/x86/mm/fault.c:1385
handle_page_fault arch/x86/mm/fault.c:1474 [inline]
exc_page_fault+0x62/0xa0 arch/x86/mm/fault.c:1527
asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618
__put_user_nocheck_4+0x3/0x10 arch/x86/lib/putuser.S:97
____sys_recvmsg+0x1a1/0x280 net/socket.c:2931
___sys_recvmsg+0x11f/0x3b0 net/socket.c:2960
do_recvmmsg+0x1ef/0x560 net/socket.c:3055
__sys_recvmmsg net/socket.c:3129 [inline]
__do_sys_recvmmsg net/socket.c:3152 [inline]
__se_sys_recvmmsg net/socket.c:3145 [inline]
__x64_sys_recvmmsg+0xe5/0x170 net/socket.c:3145
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/0x3b0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x0000000000000000 -> 0xffff888119e6fde0

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 14993 Comm: syz.4.3335 Tainted: G W syzkaller #0 PREEMPT(full)
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
==================================================================


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