==================================================================
BUG: KCSAN: data-race in mark_buffer_dirty_inode / sync_mapping_buffers

write to 0xffff888106ad71f8 of 8 bytes by task 5429 on cpu 1:
 __remove_assoc_queue fs/buffer.c:514 [inline]
 fsync_buffers_list fs/buffer.c:785 [inline]
 sync_mapping_buffers+0x159/0x7c0 fs/buffer.c:575
 fat_file_fsync+0xa7/0x100 fs/fat/file.c:195
 vfs_fsync_range+0x116/0x130 fs/sync.c:187
 generic_write_sync include/linux/fs.h:2904 [inline]
 generic_file_write_iter+0x185/0x1c0 mm/filemap.c:4186
 new_sync_write fs/read_write.c:586 [inline]
 vfs_write+0x77f/0x920 fs/read_write.c:679
 ksys_write+0xe8/0x1b0 fs/read_write.c:731
 __do_sys_write fs/read_write.c:742 [inline]
 __se_sys_write fs/read_write.c:739 [inline]
 __x64_sys_write+0x42/0x50 fs/read_write.c:739
 x64_sys_call+0x287e/0x2dc0 arch/x86/include/generated/asm/syscalls_64.h:2
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff888106ad71f8 of 8 bytes by task 5444 on cpu 0:
 mark_buffer_dirty_inode+0x96/0x1c0 fs/buffer.c:678
 fat16_ent_put+0x4f/0x60 fs/fat/fatent.c:184
 fat_free_clusters+0x2a6/0x7a0 fs/fat/fatent.c:597
 fat_free fs/fat/file.c:376 [inline]
 fat_truncate_blocks+0x4a8/0x530 fs/fat/file.c:394
 fat_setattr+0x734/0x840 fs/fat/file.c:551
 notify_change+0x85c/0x8e0 fs/attr.c:552
 do_truncate+0x116/0x160 fs/open.c:65
 handle_truncate fs/namei.c:3449 [inline]
 do_open fs/namei.c:3832 [inline]
 path_openat+0x1c03/0x1fa0 fs/namei.c:3987
 do_filp_open+0x107/0x230 fs/namei.c:4014
 do_sys_openat2+0xab/0x120 fs/open.c:1402
 do_sys_open fs/open.c:1417 [inline]
 __do_sys_open fs/open.c:1425 [inline]
 __se_sys_open fs/open.c:1421 [inline]
 __x64_sys_open+0xe6/0x110 fs/open.c:1421
 x64_sys_call+0x13e1/0x2dc0 arch/x86/include/generated/asm/syscalls_64.h:3
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0xffff888106b9f208 -> 0x0000000000000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 5444 Comm: syz.1.611 Not tainted 6.13.0-rc4-syzkaller-00069-g8379578b11d5 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
==================================================================