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BUG: KCSAN: data-race in filemap_fault / generic_write_end

write to 0xffff88812192d378 of 8 bytes by task 4623 on cpu 0:
 i_size_write include/linux/fs.h:886 [inline]
 generic_write_end+0xb1/0x350 fs/buffer.c:2183
 ext4_da_write_end+0x26c/0x620 fs/ext4/inode.c:3089
 generic_perform_write+0x264/0x3f0 mm/filemap.c:3749
 ext4_buffered_write_iter+0x235/0x3e0 fs/ext4/file.c:270
 ext4_file_write_iter+0x2e3/0x1210
 do_iter_write+0x494/0x750 fs/read_write.c:861
 vfs_iter_write+0x4c/0x70 fs/read_write.c:902
 iter_file_splice_write+0x44a/0x7c0 fs/splice.c:686
 do_splice_from fs/splice.c:764 [inline]
 direct_splice_actor+0x80/0xa0 fs/splice.c:931
 splice_direct_to_actor+0x305/0x620 fs/splice.c:886
 do_splice_direct+0xfb/0x180 fs/splice.c:974
 do_sendfile+0x3bf/0x910 fs/read_write.c:1255
 __do_sys_sendfile64 fs/read_write.c:1323 [inline]
 __se_sys_sendfile64 fs/read_write.c:1309 [inline]
 __x64_sys_sendfile64+0x10c/0x150 fs/read_write.c:1309
 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

read to 0xffff88812192d378 of 8 bytes by task 4634 on cpu 1:
 i_size_read include/linux/fs.h:864 [inline]
 filemap_fault+0x513/0x750 mm/filemap.c:3187
 __do_fault mm/memory.c:4173 [inline]
 do_cow_fault+0x220/0x600 mm/memory.c:4554
 do_fault+0x351/0xb20 mm/memory.c:4655
 handle_pte_fault mm/memory.c:4917 [inline]
 __handle_mm_fault mm/memory.c:5059 [inline]
 handle_mm_fault+0x889/0xa90 mm/memory.c:5157
 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: 0x000000000044d000 -> 0x000000000044e000

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 4634 Comm: syz-executor.2 Not tainted 6.0.0-rc7-syzkaller-00220-gffb4d94b4314-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/22/2022
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