==================================================================
BUG: KCSAN: data-race in copy_page_to_iter / fat16_ent_put

write to 0xffff88813c88d2ce of 2 bytes by task 3773 on cpu 0:
 fat16_ent_put+0x24/0x50 fs/fat/fatent.c:182
 fat_ent_write+0x5e/0xd0 fs/fat/fatent.c:416
 fat_chain_add+0x15b/0x410 fs/fat/misc.c:130
 fat_add_cluster fs/fat/inode.c:113 [inline]
 __fat_get_block fs/fat/inode.c:155 [inline]
 fat_get_block+0x486/0x600 fs/fat/inode.c:190
 __block_write_begin_int+0x33d/0xc90 fs/buffer.c:2006
 __block_write_begin fs/buffer.c:2056 [inline]
 block_write_begin+0x77/0x170 fs/buffer.c:2117
 cont_write_begin+0x3cf/0x500 fs/buffer.c:2463
 fat_write_begin+0x61/0xf0 fs/fat/inode.c:235
 generic_perform_write+0x1d6/0x3f0 mm/filemap.c:3793
 __generic_file_write_iter+0xe3/0x280 mm/filemap.c:3921
 generic_file_write_iter+0x75/0x130 mm/filemap.c:3953
 call_write_iter include/linux/fs.h:2050 [inline]
 new_sync_write fs/read_write.c:504 [inline]
 vfs_write+0x71c/0x890 fs/read_write.c:591
 ksys_write+0xe8/0x1a0 fs/read_write.c:644
 __do_sys_write fs/read_write.c:656 [inline]
 __se_sys_write fs/read_write.c:653 [inline]
 __x64_sys_write+0x3e/0x50 fs/read_write.c:653
 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 0xffff88813c88d000 of 4096 bytes by task 2457 on cpu 1:
 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:2736
 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: 1 PID: 2457 Comm: udevd Not tainted 5.18.0-rc2-syzkaller-00050-ga19944809fe9-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================
I/O error, dev loop1, sector 262016 op 0x0:(READ) flags 0x80700 phys_seg 1 prio class 0
I/O error, dev loop5, sector 264064 op 0x0:(READ) flags 0x80700 phys_seg 1 prio class 0
I/O error, dev loop1, sector 262016 op 0x0:(READ) flags 0x80700 phys_seg 1 prio class 0
I/O error, dev loop5, sector 264064 op 0x0:(READ) flags 0x80700 phys_seg 1 prio class 0