syzbot

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BUG: KCSAN: data-race in generic_write_end / mpage_process_page_bufs

write to 0xffff88810a8a2f18 of 8 bytes by task 20600 on cpu 1:
 i_size_write include/linux/fs.h:932 [inline]
 generic_write_end+0x94/0x230 fs/buffer.c:2280
 ext4_da_write_end+0x49e/0x6f0 fs/ext4/inode.c:2988
 generic_perform_write+0x267/0x410 mm/filemap.c:3956
 ext4_buffered_write_iter+0x1f6/0x370 fs/ext4/file.c:299
 ext4_file_write_iter+0x283/0x1230
 do_iter_write+0x4b4/0x7b0 fs/read_write.c:860
 vfs_iter_write+0x56/0x70 fs/read_write.c:901
 iter_file_splice_write+0x462/0x7e0 fs/splice.c:736
 do_splice_from fs/splice.c:933 [inline]
 direct_splice_actor+0x8a/0xb0 fs/splice.c:1142
 splice_direct_to_actor+0x31d/0x690 fs/splice.c:1088
 do_splice_direct+0x10d/0x190 fs/splice.c:1194
 do_sendfile+0x3b6/0x9a0 fs/read_write.c:1254
 __do_sys_sendfile64 fs/read_write.c:1322 [inline]
 __se_sys_sendfile64 fs/read_write.c:1308 [inline]
 __x64_sys_sendfile64+0x110/0x150 fs/read_write.c:1308
 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 0xffff88810a8a2f18 of 8 bytes by task 20599 on cpu 0:
 i_size_read include/linux/fs.h:910 [inline]
 mpage_process_page_bufs+0x34/0x5d0 fs/ext4/inode.c:1956
 mpage_prepare_extent_to_map+0x780/0xb70 fs/ext4/inode.c:2487
 ext4_do_writepages+0xa52/0x21c0 fs/ext4/inode.c:2675
 ext4_writepages+0x15e/0x2e0 fs/ext4/inode.c:2766
 do_writepages+0x1c2/0x340 mm/page-writeback.c:2553
 filemap_fdatawrite_wbc+0xdb/0xf0 mm/filemap.c:393
 __filemap_fdatawrite_range mm/filemap.c:426 [inline]
 __filemap_fdatawrite mm/filemap.c:432 [inline]
 filemap_flush+0x95/0xc0 mm/filemap.c:459
 ext4_alloc_da_blocks+0x50/0x130 fs/ext4/inode.c:3033
 ext4_release_file+0x5f/0x1c0 fs/ext4/file.c:169
 __fput+0x2fd/0x5f0 fs/file_table.c:384
 __fput_sync+0x44/0x50 fs/file_table.c:465
 __do_sys_close fs/open.c:1572 [inline]
 __se_sys_close+0xfa/0x1a0 fs/open.c:1557
 __x64_sys_close+0x1f/0x30 fs/open.c:1557
 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: 0x0000000001cfb000 -> 0x0000000001cfc000

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 20599 Comm: syz-executor.0 Not tainted 6.5.0-syzkaller-08894-gb97d64c72259 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023
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