syzbot

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BUG: KCSAN: data-race in __anon_vma_prepare / __vmf_anon_prepare

write to 0xffff88811a6a4d00 of 8 bytes by task 20911 on cpu 1:
 __anon_vma_prepare+0x172/0x2f0 mm/rmap.c:212
 __vmf_anon_prepare+0x91/0x100 mm/memory.c:3829
 hugetlb_no_page+0x1b8/0xf30 mm/hugetlb.c:5756
 hugetlb_fault+0x608/0xda0 mm/hugetlb.c:-1
 handle_mm_fault+0x1de9/0x2da0 mm/memory.c:6684
 faultin_page mm/gup.c:1126 [inline]
 __get_user_pages+0x129c/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:4171 [inline]
 vm_mmap_pgoff+0x23b/0x2d0 mm/util.c:586
 ksys_mmap_pgoff+0x2c6/0x310 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+0x136/0x3c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff88811a6a4d00 of 8 bytes by task 20901 on cpu 0:
 __vmf_anon_prepare+0x26/0x100 mm/memory.c:3823
 hugetlb_no_page+0x1b8/0xf30 mm/hugetlb.c:5756
 hugetlb_fault+0x608/0xda0 mm/hugetlb.c:-1
 handle_mm_fault+0x1de9/0x2da0 mm/memory.c:6684
 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_nocheck_4+0x3/0x20 arch/x86/lib/putuser.S:97
 ____sys_recvmsg+0x1a1/0x280 net/socket.c:2917
 ___sys_recvmsg+0x11f/0x3a0 net/socket.c:2946
 do_recvmmsg+0x1e5/0x560 net/socket.c:3041
 __sys_recvmmsg net/socket.c:3115 [inline]
 __do_sys_recvmmsg net/socket.c:3138 [inline]
 __se_sys_recvmmsg net/socket.c:3131 [inline]
 __x64_sys_recvmmsg+0xe5/0x170 net/socket.c:3131
 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+0x136/0x3c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x0000000000000000 -> 0xffff8881020cec60

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 20901 Comm: syz.0.4316 Tainted: G        W           syzkaller #0 PREEMPT(lazy) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
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