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BUG: KCSAN: data-race in ext4_write_end / mpage_process_page_bufs

write to 0xffff888104b55c88 of 8 bytes by task 25941 on cpu 0:
 i_size_write include/linux/fs.h:913 [inline]
 ext4_update_inode_size fs/ext4/ext4.h:3421 [inline]
 ext4_write_end+0x16d/0x710 fs/ext4/inode.c:1303
 ext4_da_write_end+0x6d/0x630 fs/ext4/inode.c:3029
 generic_perform_write+0x261/0x400 mm/filemap.c:3757
 ext4_buffered_write_iter+0x25b/0x380 fs/ext4/file.c:269
 ext4_file_write_iter+0x2e7/0x1200
 call_write_iter include/linux/fs.h:2161 [inline]
 aio_write+0x2dc/0x3c0 fs/aio.c:1577
 io_submit_one+0x8c4/0x1380 fs/aio.c:1879
 __do_sys_io_submit fs/aio.c:1938 [inline]
 __se_sys_io_submit+0x105/0x280 fs/aio.c:1908
 __x64_sys_io_submit+0x3f/0x50 fs/aio.c:1908
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff888104b55c88 of 8 bytes by task 11276 on cpu 1:
 i_size_read include/linux/fs.h:891 [inline]
 mpage_process_page_bufs+0x34/0x560 fs/ext4/inode.c:2190
 mpage_prepare_extent_to_map+0x4f6/0x650 fs/ext4/inode.c:2624
 ext4_writepages+0xa78/0x1e80 fs/ext4/inode.c:2796
 do_writepages+0x1cb/0x320 mm/page-writeback.c:2364
 __writeback_single_inode+0x80/0x4d0 fs/fs-writeback.c:1616
 writeback_sb_inodes+0x677/0xdf0 fs/fs-writeback.c:1881
 __writeback_inodes_wb+0xb0/0x2b0 fs/fs-writeback.c:1951
 wb_writeback+0x280/0x650 fs/fs-writeback.c:2056
 wb_check_start_all fs/fs-writeback.c:2178 [inline]
 wb_do_writeback+0x378/0x560 fs/fs-writeback.c:2204
 wb_workfn+0xc8/0x440 fs/fs-writeback.c:2238
 process_one_work+0x3fc/0x980 kernel/workqueue.c:2298
 worker_thread+0x616/0xa70 kernel/workqueue.c:2445
 kthread+0x2c7/0x2e0 kernel/kthread.c:327
 ret_from_fork+0x1f/0x30

value changed: 0x0000000000161000 -> 0x0000000000162000

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 11276 Comm: kworker/u4:0 Not tainted 5.15.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: writeback wb_workfn (flush-7:1)
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