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BUG: KCSAN: data-race in __anon_vma_prepare / wp_page_copy

write to 0xffff888180f52b08 of 8 bytes by task 13219 on cpu 0:
 __anon_vma_prepare+0x12f/0x2d0 mm/rmap.c:207
 anon_vma_prepare include/linux/rmap.h:153 [inline]
 wp_page_copy+0xb06/0x10c0 mm/memory.c:2898
 do_wp_page+0x5a8/0xba0 include/linux/spinlock_api_smp.h:152
 handle_pte_fault mm/memory.c:4430 [inline]
 __handle_mm_fault mm/memory.c:4547 [inline]
 handle_mm_fault+0xb31/0x1a70 mm/memory.c:4645
 do_user_addr_fault+0x609/0xc00 arch/x86/mm/fault.c:1390
 handle_page_fault arch/x86/mm/fault.c:1475 [inline]
 exc_page_fault+0x91/0x230 arch/x86/mm/fault.c:1531
 asm_exc_page_fault+0x1e/0x30 arch/x86/include/asm/idtentry.h:577

read to 0xffff888180f52b08 of 8 bytes by task 13234 on cpu 1:
 anon_vma_prepare include/linux/rmap.h:150 [inline]
 wp_page_copy+0x5f/0x10c0 mm/memory.c:2898
 do_wp_page+0x5a8/0xba0 include/linux/spinlock_api_smp.h:152
 handle_pte_fault mm/memory.c:4430 [inline]
 __handle_mm_fault mm/memory.c:4547 [inline]
 handle_mm_fault+0xb31/0x1a70 mm/memory.c:4645
 do_user_addr_fault+0x609/0xc00 arch/x86/mm/fault.c:1390
 handle_page_fault arch/x86/mm/fault.c:1475 [inline]
 exc_page_fault+0x91/0x230 arch/x86/mm/fault.c:1531
 asm_exc_page_fault+0x1e/0x30 arch/x86/include/asm/idtentry.h:577
 copy_user_generic_unrolled+0x89/0xc0 arch/x86/lib/copy_user_64.S:91
 copy_user_generic arch/x86/include/asm/uaccess_64.h:37 [inline]
 raw_copy_to_user arch/x86/include/asm/uaccess_64.h:58 [inline]
 _copy_to_user+0x77/0x90 lib/usercopy.c:33
 copy_to_user include/linux/uaccess.h:200 [inline]
 copy_event_to_user fs/notify/inotify/inotify_user.c:197 [inline]
 inotify_read+0x290/0x460 fs/notify/inotify/inotify_user.c:246
 do_loop_readv_writev fs/read_write.c:761 [inline]
 do_iter_read+0x2be/0x4b0 fs/read_write.c:803
 vfs_readv fs/read_write.c:921 [inline]
 do_readv+0x13d/0x290 fs/read_write.c:958
 __do_sys_readv fs/read_write.c:1049 [inline]
 __se_sys_readv fs/read_write.c:1046 [inline]
 __x64_sys_readv+0x41/0x50 fs/read_write.c:1046
 do_syscall_64+0x4a/0x90 arch/x86/entry/common.c:47
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x0000000000000000 -> 0xffff88817e6cdbe0

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 13234 Comm: syz-executor.4 Not tainted 5.13.0-rc7-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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