==================================================================
BUG: KCSAN: data-race in __fat_write_inode / copy_page_to_iter

write to 0xffff88810d27c63c of 4 bytes by task 410 on cpu 1:
 __fat_write_inode+0x23e/0x4e0 fs/fat/inode.c:882
 fat_write_inode+0xb9/0xd0 fs/fat/inode.c:916
 write_inode+0x89/0x1f0 fs/fs-writeback.c:1434
 __writeback_single_inode+0x2c6/0x590 fs/fs-writeback.c:1646
 writeback_single_inode+0x128/0x3c0 fs/fs-writeback.c:1702
 sync_inode_metadata+0x52/0x70 fs/fs-writeback.c:2717
 __generic_file_fsync+0xf5/0x140 fs/libfs.c:1126
 fat_file_fsync+0x48/0x100 fs/fat/file.c:191
 vfs_fsync_range+0x107/0x120 fs/sync.c:188
 generic_write_sync include/linux/fs.h:2732 [inline]
 generic_file_write_iter+0x103/0x130 mm/filemap.c:3951
 do_iter_readv_writev+0x27b/0x300
 do_iter_write+0x16f/0x5c0 fs/read_write.c:852
 vfs_iter_write+0x4c/0x70 fs/read_write.c:893
 iter_file_splice_write+0x44a/0x7c0 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+0x345/0x660 fs/splice.c:891
 do_splice_direct+0xfb/0x180 fs/splice.c:979
 do_sendfile+0x3ad/0x900 fs/read_write.c:1246
 __do_sys_sendfile64 fs/read_write.c:1305 [inline]
 __se_sys_sendfile64 fs/read_write.c:1297 [inline]
 __x64_sys_sendfile64+0xb9/0x150 fs/read_write.c:1297
 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 0xffff88810d27c000 of 4096 bytes by task 29575 on cpu 0:
 instrument_copy_to_user include/linux/instrumented.h:119 [inline]
 copyout lib/iov_iter.c:154 [inline]
 copy_page_to_iter_iovec lib/iov_iter.c:226 [inline]
 __copy_page_to_iter lib/iov_iter.c:852 [inline]
 copy_page_to_iter+0x415/0x7b0 lib/iov_iter.c:880
 copy_folio_to_iter include/linux/uio.h:153 [inline]
 filemap_read+0x10b2/0x1400 mm/filemap.c:2730
 blkdev_read_iter+0x2c6/0x370 block/fops.c:611
 call_read_iter include/linux/fs.h:2044 [inline]
 new_sync_read fs/read_write.c:401 [inline]
 vfs_read+0x5a5/0x6a0 fs/read_write.c:482
 ksys_read+0xe8/0x1a0 fs/read_write.c:620
 __do_sys_read fs/read_write.c:630 [inline]
 __se_sys_read fs/read_write.c:628 [inline]
 __x64_sys_read+0x3e/0x50 fs/read_write.c:628
 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

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 29575 Comm: udevd Not tainted 5.18.0-rc5-syzkaller-00178-g30c8e80f7932-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================