syz-executor.1: attempt to access beyond end of device
loop1: rw=2049, sector=1800, nr_sectors = 2048 limit=256
syz-executor.1: attempt to access beyond end of device
loop1: rw=2049, sector=3848, nr_sectors = 3592 limit=256
==================================================================
BUG: KCSAN: data-race in __mpage_writepage / generic_write_end

write to 0xffff888107b89f38 of 8 bytes by task 22452 on cpu 1:
 i_size_write include/linux/fs.h:932 [inline]
 generic_write_end+0x94/0x230 fs/buffer.c:2275
 fat_write_end+0x4e/0x160 fs/fat/inode.c:244
 generic_perform_write+0x267/0x410 mm/filemap.c:3939
 __generic_file_write_iter+0xa1/0x120 mm/filemap.c:4023
 generic_file_write_iter+0x7d/0x1c0 mm/filemap.c:4049
 call_write_iter include/linux/fs.h:2085 [inline]
 new_sync_write fs/read_write.c:497 [inline]
 vfs_write+0x430/0x6b0 fs/read_write.c:590
 ksys_write+0xeb/0x1a0 fs/read_write.c:643
 __do_sys_write fs/read_write.c:655 [inline]
 __se_sys_write fs/read_write.c:652 [inline]
 __x64_sys_write+0x42/0x50 fs/read_write.c:652
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0x59/0x120 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

read to 0xffff888107b89f38 of 8 bytes by task 22469 on cpu 0:
 i_size_read include/linux/fs.h:910 [inline]
 __mpage_writepage+0xa6/0xdc0 fs/mpage.c:478
 write_cache_pages+0x38d/0x740 mm/page-writeback.c:2474
 mpage_writepages+0x72/0xe0 fs/mpage.c:672
 fat_writepages+0x24/0x30 fs/fat/inode.c:200
 do_writepages+0x1c2/0x340 mm/page-writeback.c:2553
 filemap_fdatawrite_wbc+0xdb/0xf0 mm/filemap.c:388
 __filemap_fdatawrite_range mm/filemap.c:421 [inline]
 file_write_and_wait_range+0xf4/0x190 mm/filemap.c:779
 __generic_file_fsync+0x4c/0x140 fs/libfs.c:1448
 fat_file_fsync+0x4c/0x100 fs/fat/file.c:191
 vfs_fsync_range fs/sync.c:188 [inline]
 vfs_fsync fs/sync.c:202 [inline]
 do_fsync fs/sync.c:212 [inline]
 __do_sys_fdatasync fs/sync.c:225 [inline]
 __se_sys_fdatasync fs/sync.c:223 [inline]
 __x64_sys_fdatasync+0x84/0xd0 fs/sync.c:223
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0x59/0x120 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

value changed: 0x000000000084f000 -> 0x0000000000850000

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 22469 Comm: syz-executor.1 Tainted: G        W          6.7.0-syzkaller-02723-gde927f6c0b07 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023
==================================================================
syz-executor.1: attempt to access beyond end of device
loop1: rw=2049, sector=7440, nr_sectors = 2376 limit=256