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BUG: KCSAN: data-race in ext4_file_write_iter / generic_write_end

write to 0xffff88810cd357c8 of 8 bytes by task 14001 on cpu 0:
 i_size_write include/linux/fs.h:878 [inline]
 generic_write_end+0x98/0x230 fs/buffer.c:2183
 ext4_da_write_end+0x26c/0x620 fs/ext4/inode.c:3068
 generic_perform_write+0x26a/0x3f0 mm/filemap.c:3798
 ext4_buffered_write_iter+0x222/0x330 fs/ext4/file.c:270
 ext4_file_write_iter+0x2e3/0x1210
 call_write_iter include/linux/fs.h:2050 [inline]
 new_sync_write fs/read_write.c:504 [inline]
 vfs_write+0x71c/0x890 fs/read_write.c:591
 ksys_write+0xe8/0x1a0 fs/read_write.c:644
 __do_sys_write fs/read_write.c:656 [inline]
 __se_sys_write fs/read_write.c:653 [inline]
 __x64_sys_write+0x3e/0x50 fs/read_write.c:653
 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+0x44/0xae

read to 0xffff88810cd357c8 of 8 bytes by task 14015 on cpu 1:
 i_size_read include/linux/fs.h:856 [inline]
 ext4_dio_write_iter fs/ext4/file.c:495 [inline]
 ext4_file_write_iter+0x14b/0x1210 fs/ext4/file.c:677
 call_write_iter include/linux/fs.h:2050 [inline]
 aio_write+0x2e0/0x3c0 fs/aio.c:1603
 io_submit_one+0x89b/0x1190 fs/aio.c:2022
 __do_sys_io_submit fs/aio.c:2081 [inline]
 __se_sys_io_submit+0x105/0x280 fs/aio.c:2051
 __x64_sys_io_submit+0x3f/0x50 fs/aio.c:2051
 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+0x44/0xae

value changed: 0x00000000000a7000 -> 0x00000000000a8000

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 14015 Comm: syz-executor.0 Not tainted 5.18.0-rc5-syzkaller-00207-g379c72654524 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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