syzbot

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BUG: KCSAN: data-race in __anon_vma_prepare / do_cow_fault

write to 0xffff8881398f6ec8 of 8 bytes by task 21223 on cpu 0:
 __anon_vma_prepare+0x12c/0x2a0 mm/rmap.c:211
 anon_vma_prepare include/linux/rmap.h:156 [inline]
 do_cow_fault+0x3b8/0x600 mm/memory.c:4534
 do_fault+0x351/0xb20 mm/memory.c:4649
 handle_pte_fault mm/memory.c:4911 [inline]
 __handle_mm_fault mm/memory.c:5053 [inline]
 handle_mm_fault+0x889/0xa90 mm/memory.c:5151
 do_user_addr_fault+0x4a1/0x980 arch/x86/mm/fault.c:1397
 handle_page_fault arch/x86/mm/fault.c:1488 [inline]
 exc_page_fault+0x60/0x160 arch/x86/mm/fault.c:1544
 asm_exc_page_fault+0x22/0x30

read to 0xffff8881398f6ec8 of 8 bytes by task 21235 on cpu 1:
 anon_vma_prepare include/linux/rmap.h:153 [inline]
 do_cow_fault+0x29/0x600 mm/memory.c:4534
 do_fault+0x351/0xb20 mm/memory.c:4649
 handle_pte_fault mm/memory.c:4911 [inline]
 __handle_mm_fault mm/memory.c:5053 [inline]
 handle_mm_fault+0x889/0xa90 mm/memory.c:5151
 faultin_page mm/gup.c:990 [inline]
 __get_user_pages+0x34a/0xc40 mm/gup.c:1219
 populate_vma_page_range mm/gup.c:1576 [inline]
 __mm_populate+0x26e/0x3a0 mm/gup.c:1689
 mm_populate include/linux/mm.h:2663 [inline]
 vm_mmap_pgoff+0x160/0x1f0 mm/util.c:557
 ksys_mmap_pgoff+0x265/0x320 mm/mmap.c:1586
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

value changed: 0x0000000000000000 -> 0xffff888141beaeb0

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 21235 Comm: syz-executor.4 Tainted: G        W          6.0.0-rc3-syzkaller-00007-gdcf8e5633e2e-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/22/2022
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