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BUG: KCSAN: data-race in mark_buffer_dirty_inode / sync_mapping_buffers

write to 0xffff8881089c6d58 of 8 bytes by task 5588 on cpu 0:
 __remove_assoc_queue fs/buffer.c:517 [inline]
 fsync_buffers_list fs/buffer.c:785 [inline]
 sync_mapping_buffers+0x165/0x7d0 fs/buffer.c:578
 fat_file_fsync+0xad/0x100 fs/fat/file.c:195
 vfs_fsync_range+0x111/0x120 fs/sync.c:188
 generic_write_sync include/linux/fs.h:2653 [inline]
 generic_file_write_iter+0x191/0x1c0 mm/filemap.c:4043
 do_iter_write+0x4ad/0x770 fs/read_write.c:860
 vfs_iter_write+0x56/0x70 fs/read_write.c:901
 iter_file_splice_write+0x462/0x7e0 fs/splice.c:736
 do_splice_from fs/splice.c:933 [inline]
 direct_splice_actor+0x8a/0xb0 fs/splice.c:1142
 splice_direct_to_actor+0x31d/0x690 fs/splice.c:1088
 do_splice_direct+0x10d/0x190 fs/splice.c:1194
 do_sendfile+0x3c4/0x980 fs/read_write.c:1254
 __do_sys_sendfile64 fs/read_write.c:1316 [inline]
 __se_sys_sendfile64 fs/read_write.c:1308 [inline]
 __x64_sys_sendfile64+0xbd/0x150 fs/read_write.c:1308
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x44/0x110 arch/x86/entry/common.c:82
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

read to 0xffff8881089c6d58 of 8 bytes by task 5593 on cpu 1:
 mark_buffer_dirty_inode+0x96/0x1c0 fs/buffer.c:681
 fat16_ent_put+0x4f/0x60 fs/fat/fatent.c:184
 fat_ent_write+0x62/0xe0 fs/fat/fatent.c:417
 fat_chain_add+0x15f/0x400 fs/fat/misc.c:136
 fat_add_cluster+0x78/0xd0 fs/fat/inode.c:113
 fat_fallocate+0x129/0x1d0 fs/fat/file.c:292
 vfs_fallocate+0x378/0x3e0 fs/open.c:324
 do_vfs_ioctl+0x12e6/0x13a0 fs/ioctl.c:850
 __do_sys_ioctl fs/ioctl.c:869 [inline]
 __se_sys_ioctl+0x81/0x140 fs/ioctl.c:857
 __x64_sys_ioctl+0x43/0x50 fs/ioctl.c:857
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x44/0x110 arch/x86/entry/common.c:82
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

value changed: 0xffff888108a8d440 -> 0x0000000000000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 5593 Comm: syz-executor.3 Not tainted 6.6.0-syzkaller-12401-g8f6f76a6a29f #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/09/2023
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