==================================================================
BUG: KCSAN: data-race in generic_write_end / mpage_process_page_bufs

write to 0xffff88811e8db2e8 of 8 bytes by task 10085 on cpu 0:
 i_size_write include/linux/fs.h:907 [inline]
 generic_write_end+0x96/0x180 fs/buffer.c:2187
 ext4_da_write_end+0x4de/0x630 fs/ext4/inode.c:3042
 generic_perform_write+0x261/0x400 mm/filemap.c:3776
 ext4_buffered_write_iter+0x244/0x360 fs/ext4/file.c:268
 ext4_file_write_iter+0x2e7/0x11f0
 call_write_iter include/linux/fs.h:2074 [inline]
 do_iter_readv_writev+0x2de/0x380 fs/read_write.c:725
 do_iter_write+0x192/0x5c0 fs/read_write.c:851
 vfs_iter_write+0x4c/0x70 fs/read_write.c:892
 iter_file_splice_write+0x43a/0x790 fs/splice.c:689
 do_splice_from fs/splice.c:767 [inline]
 direct_splice_actor+0x80/0xa0 fs/splice.c:936
 splice_direct_to_actor+0x345/0x650 fs/splice.c:891
 do_splice_direct+0x106/0x190 fs/splice.c:979
 do_sendfile+0x675/0xc40 fs/read_write.c:1245
 __do_sys_sendfile64 fs/read_write.c:1310 [inline]
 __se_sys_sendfile64 fs/read_write.c:1296 [inline]
 __x64_sys_sendfile64+0x102/0x140 fs/read_write.c:1296
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff88811e8db2e8 of 8 bytes by task 10084 on cpu 1:
 i_size_read include/linux/fs.h:885 [inline]
 mpage_process_page_bufs+0x34/0x560 fs/ext4/inode.c:2172
 mpage_prepare_extent_to_map+0x4f6/0x650 fs/ext4/inode.c:2604
 ext4_writepages+0xa78/0x1e80 fs/ext4/inode.c:2776
 do_writepages+0x1cb/0x330 mm/page-writeback.c:2364
 filemap_fdatawrite_wbc mm/filemap.c:384 [inline]
 __filemap_fdatawrite_range mm/filemap.c:417 [inline]
 __filemap_fdatawrite mm/filemap.c:423 [inline]
 filemap_flush+0xd9/0x100 mm/filemap.c:450
 ext4_alloc_da_blocks+0x47/0x100 fs/ext4/inode.c:3086
 ext4_release_file+0x5b/0x1d0 fs/ext4/file.c:141
 __fput+0x295/0x520 fs/file_table.c:311
 ____fput+0x11/0x20 fs/file_table.c:344
 task_work_run+0x8e/0x110 kernel/task_work.c:164
 tracehook_notify_resume include/linux/tracehook.h:188 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:175 [inline]
 exit_to_user_mode_prepare+0x160/0x190 kernel/entry/common.c:207
 __syscall_exit_to_user_mode_work kernel/entry/common.c:289 [inline]
 syscall_exit_to_user_mode+0x20/0x40 kernel/entry/common.c:300
 do_syscall_64+0x50/0xd0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x000000000446a000 -> 0x000000000446b601

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 10084 Comm: syz-executor.5 Not tainted 5.17.0-rc2-syzkaller-00039-g9f7fb8de5d9b #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================
==================================================================
BUG: KCSAN: data-race in ext4_writepages / generic_write_end

write to 0xffff88811e8db2e8 of 8 bytes by task 10085 on cpu 1:
 i_size_write include/linux/fs.h:907 [inline]
 generic_write_end+0x96/0x180 fs/buffer.c:2187
 ext4_da_write_end+0x4de/0x630 fs/ext4/inode.c:3042
 generic_perform_write+0x261/0x400 mm/filemap.c:3776
 ext4_buffered_write_iter+0x244/0x360 fs/ext4/file.c:268
 ext4_file_write_iter+0x2e7/0x11f0
 call_write_iter include/linux/fs.h:2074 [inline]
 do_iter_readv_writev+0x2de/0x380 fs/read_write.c:725
 do_iter_write+0x192/0x5c0 fs/read_write.c:851
 vfs_iter_write+0x4c/0x70 fs/read_write.c:892
 iter_file_splice_write+0x43a/0x790 fs/splice.c:689
 do_splice_from fs/splice.c:767 [inline]
 direct_splice_actor+0x80/0xa0 fs/splice.c:936
 splice_direct_to_actor+0x345/0x650 fs/splice.c:891
 do_splice_direct+0x106/0x190 fs/splice.c:979
 do_sendfile+0x675/0xc40 fs/read_write.c:1245
 __do_sys_sendfile64 fs/read_write.c:1310 [inline]
 __se_sys_sendfile64 fs/read_write.c:1296 [inline]
 __x64_sys_sendfile64+0x102/0x140 fs/read_write.c:1296
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff88811e8db2e8 of 8 bytes by task 10084 on cpu 0:
 i_size_read include/linux/fs.h:885 [inline]
 mpage_submit_page fs/ext4/inode.c:2074 [inline]
 mpage_map_and_submit_buffers fs/ext4/inode.c:2326 [inline]
 mpage_map_and_submit_extent fs/ext4/inode.c:2465 [inline]
 ext4_writepages+0x10b6/0x1e80 fs/ext4/inode.c:2778
 do_writepages+0x1cb/0x330 mm/page-writeback.c:2364
 filemap_fdatawrite_wbc mm/filemap.c:384 [inline]
 __filemap_fdatawrite_range mm/filemap.c:417 [inline]
 __filemap_fdatawrite mm/filemap.c:423 [inline]
 filemap_flush+0xd9/0x100 mm/filemap.c:450
 ext4_alloc_da_blocks+0x47/0x100 fs/ext4/inode.c:3086
 ext4_release_file+0x5b/0x1d0 fs/ext4/file.c:141
 __fput+0x295/0x520 fs/file_table.c:311
 ____fput+0x11/0x20 fs/file_table.c:344
 task_work_run+0x8e/0x110 kernel/task_work.c:164
 tracehook_notify_resume include/linux/tracehook.h:188 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:175 [inline]
 exit_to_user_mode_prepare+0x160/0x190 kernel/entry/common.c:207
 __syscall_exit_to_user_mode_work kernel/entry/common.c:289 [inline]
 syscall_exit_to_user_mode+0x20/0x40 kernel/entry/common.c:300
 do_syscall_64+0x50/0xd0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x0000000005f5e000 -> 0x0000000005f60000

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 10084 Comm: syz-executor.5 Not tainted 5.17.0-rc2-syzkaller-00039-g9f7fb8de5d9b #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================