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BUG: KCSAN: data-race in block_page_mkwrite / generic_write_end

write to 0xffff88810a5ecbd8 of 8 bytes by task 5485 on cpu 0:
 i_size_write include/linux/fs.h:888 [inline]
 generic_write_end+0xb4/0x360 fs/buffer.c:2211
 ext4_da_write_end+0x4bd/0x630 fs/ext4/inode.c:3174
 generic_perform_write+0x253/0x3d0 mm/filemap.c:3937
 ext4_buffered_write_iter+0x234/0x3e0 fs/ext4/file.c:289
 ext4_file_write_iter+0xd7/0x10e0
 call_write_iter include/linux/fs.h:1851 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x45a/0x750 fs/read_write.c:584
 ksys_write+0xeb/0x1a0 fs/read_write.c:637
 __do_sys_write fs/read_write.c:649 [inline]
 __se_sys_write fs/read_write.c:646 [inline]
 __x64_sys_write+0x42/0x50 fs/read_write.c:646
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

read to 0xffff88810a5ecbd8 of 8 bytes by task 5491 on cpu 1:
 i_size_read include/linux/fs.h:866 [inline]
 block_page_mkwrite+0xca/0x340 fs/buffer.c:2544
 ext4_page_mkwrite+0x817/0xff0 fs/ext4/inode.c:6252
 do_page_mkwrite mm/memory.c:2925 [inline]
 wp_page_shared mm/memory.c:3274 [inline]
 do_wp_page+0x4b5/0x1f90 mm/memory.c:3356
 handle_pte_fault mm/memory.c:4927 [inline]
 __handle_mm_fault mm/memory.c:5051 [inline]
 handle_mm_fault+0x64e/0x21d0 mm/memory.c:5197
 do_user_addr_fault arch/x86/mm/fault.c:1407 [inline]
 handle_page_fault arch/x86/mm/fault.c:1498 [inline]
 exc_page_fault+0x45f/0x640 arch/x86/mm/fault.c:1554
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:570
 copy_user_enhanced_fast_string+0xe/0x40 arch/x86/lib/copy_user_64.S:165
 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]
 copyout+0x72/0x90 lib/iov_iter.c:170
 _copy_to_iter+0x274/0x8f0 lib/iov_iter.c:523
 copy_page_to_iter+0x1a8/0x310 lib/iov_iter.c:721
 copy_folio_to_iter include/linux/uio.h:174 [inline]
 filemap_read+0x438/0x680 mm/filemap.c:2745
 generic_file_read_iter+0x76/0x320 mm/filemap.c:2840
 ext4_file_read_iter+0x1cc/0x290
 do_iter_read+0x3fd/0x6d0 fs/read_write.c:796
 vfs_readv fs/read_write.c:916 [inline]
 do_preadv+0x159/0x230 fs/read_write.c:1008
 __do_sys_preadv fs/read_write.c:1058 [inline]
 __se_sys_preadv fs/read_write.c:1053 [inline]
 __x64_sys_preadv+0x58/0x60 fs/read_write.c:1053
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

value changed: 0x0000000000d13000 -> 0x0000000000d14000

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 5491 Comm: syz-executor.0 Not tainted 6.3.0-rc3-syzkaller-00394-g0ec57cfa721f #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/02/2023
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syz-executor.0 (5491) used greatest stack depth: 10496 bytes left