==================================================================
BUG: KCSAN: data-race in __filemap_add_folio / file_write_and_wait_range

read-write to 0xffff88813e02de90 of 8 bytes by task 5929 on cpu 1:
 __filemap_add_folio+0x38c/0x720 mm/filemap.c:904
 filemap_add_folio+0x6f/0x150 mm/filemap.c:939
 __filemap_get_folio+0x554/0x750 mm/filemap.c:1981
 pagecache_get_page+0x2a/0xd0 mm/folio-compat.c:99
 grab_cache_page_write_begin+0x2e/0x40 mm/folio-compat.c:111
 block_write_begin+0x32/0x180 fs/buffer.c:2141
 cont_write_begin+0x4c0/0x6f0 fs/buffer.c:2504
 fat_write_begin+0x61/0xf0 fs/fat/inode.c:230
 generic_perform_write+0x1c3/0x3d0 mm/filemap.c:3926
 __generic_file_write_iter+0xe6/0x290 mm/filemap.c:4054
 generic_file_write_iter+0x7d/0x1c0 mm/filemap.c:4086
 do_iter_write+0x418/0x700 fs/read_write.c:861
 vfs_iter_write+0x50/0x70 fs/read_write.c:902
 iter_file_splice_write+0x456/0x7d0 fs/splice.c:778
 do_splice_from fs/splice.c:856 [inline]
 direct_splice_actor+0x84/0xa0 fs/splice.c:1023
 splice_direct_to_actor+0x2ee/0x5f0 fs/splice.c:978
 do_splice_direct+0x104/0x180 fs/splice.c:1066
 do_sendfile+0x3b8/0x950 fs/read_write.c:1255
 __do_sys_sendfile64 fs/read_write.c:1323 [inline]
 __se_sys_sendfile64 fs/read_write.c:1309 [inline]
 __x64_sys_sendfile64+0x110/0x150 fs/read_write.c:1309
 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 0xffff88813e02de90 of 8 bytes by task 5936 on cpu 0:
 mapping_needs_writeback mm/filemap.c:628 [inline]
 file_write_and_wait_range+0x6a/0x190 mm/filemap.c:780
 __generic_file_fsync+0x4c/0x140 fs/libfs.c:1132
 fat_file_fsync+0x4c/0x100 fs/fat/file.c:191
 vfs_fsync_range+0x10b/0x120 fs/sync.c:188
 generic_write_sync include/linux/fs.h:2452 [inline]
 generic_file_write_iter+0x191/0x1c0 mm/filemap.c:4090
 do_iter_write+0x418/0x700 fs/read_write.c:861
 vfs_iter_write+0x50/0x70 fs/read_write.c:902
 iter_file_splice_write+0x456/0x7d0 fs/splice.c:778
 do_splice_from fs/splice.c:856 [inline]
 direct_splice_actor+0x84/0xa0 fs/splice.c:1023
 splice_direct_to_actor+0x2ee/0x5f0 fs/splice.c:978
 do_splice_direct+0x104/0x180 fs/splice.c:1066
 do_sendfile+0x3b8/0x950 fs/read_write.c:1255
 __do_sys_sendfile64 fs/read_write.c:1323 [inline]
 __se_sys_sendfile64 fs/read_write.c:1309 [inline]
 __x64_sys_sendfile64+0x110/0x150 fs/read_write.c:1309
 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: 0x000000000000001d -> 0x000000000000001e

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 5936 Comm: syz-executor.0 Not tainted 6.2.0-syzkaller-12998-gc0927a7a5391-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/16/2023
==================================================================