syzbot

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BUG: KCSAN: data-race in __anon_vma_prepare / __handle_mm_fault

write to 0xffff88809bbe0470 of 8 bytes by task 9589 on cpu 0:
 __anon_vma_prepare+0xe0/0x2b0 mm/rmap.c:201
 anon_vma_prepare include/linux/rmap.h:153 [inline]
 do_anonymous_page mm/memory.c:3184 [inline]
 handle_pte_fault mm/memory.c:4031 [inline]
 __handle_mm_fault+0x2c1c/0x2e00 mm/memory.c:4163
 handle_mm_fault+0x21b/0x530 mm/memory.c:4200
 do_user_addr_fault arch/x86/mm/fault.c:1442 [inline]
 do_page_fault+0x496/0xa3d arch/x86/mm/fault.c:1517
 page_fault+0x34/0x40 arch/x86/entry/entry_64.S:1203

read to 0xffff88809bbe0470 of 8 bytes by task 9594 on cpu 1:
 anon_vma_prepare include/linux/rmap.h:150 [inline]
 do_anonymous_page mm/memory.c:3184 [inline]
 handle_pte_fault mm/memory.c:4031 [inline]
 __handle_mm_fault+0x1900/0x2e00 mm/memory.c:4163
 handle_mm_fault+0x21b/0x530 mm/memory.c:4200
 faultin_page mm/gup.c:659 [inline]
 __get_user_pages+0x485/0x1130 mm/gup.c:870
 populate_vma_page_range+0xe6/0x100 mm/gup.c:1181
 __mm_populate+0x168/0x2a0 mm/gup.c:1229
 mm_populate include/linux/mm.h:2343 [inline]
 vm_mmap_pgoff+0x181/0x190 mm/util.c:511
 ksys_mmap_pgoff+0x99/0x420 mm/mmap.c:1597
 __do_sys_mmap arch/x86/kernel/sys_x86_64.c:99 [inline]
 __se_sys_mmap arch/x86/kernel/sys_x86_64.c:90 [inline]
 __x64_sys_mmap+0x2e/0x40 arch/x86/kernel/sys_x86_64.c:90
 do_syscall_64+0xcc/0x3a0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 9594 Comm: syz-executor.5 Not tainted 5.6.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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