syzbot

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BUG: KCSAN: data-race in generic_write_end / mpage_process_page_bufs

write to 0xffff888109df6178 of 8 bytes by task 10718 on cpu 0:
 i_size_write include/linux/fs.h:905 [inline]
 generic_write_end+0xb4/0x360 fs/buffer.c:2241
 ext4_da_write_end+0x4df/0x690 fs/ext4/inode.c:3012
 generic_perform_write+0x253/0x3d0 mm/filemap.c:3934
 ext4_buffered_write_iter+0x234/0x3e0 fs/ext4/file.c:289
 ext4_file_write_iter+0xd7/0x10e0
 call_write_iter include/linux/fs.h:1868 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x47b/0x780 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 0xffff888109df6178 of 8 bytes by task 10719 on cpu 1:
 i_size_read include/linux/fs.h:883 [inline]
 mpage_process_page_bufs+0x34/0x5e0 fs/ext4/inode.c:1980
 mpage_prepare_extent_to_map+0x7b0/0xb50 fs/ext4/inode.c:2513
 ext4_do_writepages+0xa5e/0x21e0 fs/ext4/inode.c:2701
 ext4_writepages+0x15e/0x2e0 fs/ext4/inode.c:2792
 do_writepages+0x1c5/0x340 mm/page-writeback.c:2551
 filemap_fdatawrite_wbc+0xdb/0xf0 mm/filemap.c:390
 __filemap_fdatawrite_range mm/filemap.c:423 [inline]
 file_write_and_wait_range+0xfa/0x190 mm/filemap.c:781
 ext4_sync_file+0x10d/0x730 fs/ext4/fsync.c:158
 vfs_fsync_range fs/sync.c:188 [inline]
 vfs_fsync fs/sync.c:202 [inline]
 do_fsync fs/sync.c:212 [inline]
 __do_sys_fdatasync fs/sync.c:225 [inline]
 __se_sys_fdatasync fs/sync.c:223 [inline]
 __x64_sys_fdatasync+0x7e/0xd0 fs/sync.c:223
 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: 0x0000000000d9f000 -> 0x0000000000da0000

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 10719 Comm: syz-executor.2 Not tainted 6.4.0-rc5-syzkaller-00178-g33f2b5785a2b #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/25/2023
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