Linux Kernel EUVD-2026-45845

netfslib is the shared Linux kernel infrastructure layer that network/cache-backed filesystems use to manage buffered I/O, readahead, and size bookkeeping. Two of its per-inode size trackers, ->remote_i_size (the server-reported size) and ->zero_point (the offset beyond which data is treated as zero), were being updated without the same protection given to the VFS i_size field. Because these are multi-word/ordering-sensitive updates on some architectures, concurrent readers could observe a partially-updated ('torn') value. The remedy copies the i_size_read()/i_size_write() approach - a seqcount (i_size_seqcount) taken under i_lock - so all three size values are updated atomically with respect to readers. The root cause class is a concurrency/data-race defect (CWE-362 family: race condition; the input lists CWE as N/A). CPE data identifies the affected product only generically as cpe:2.3:a:linux:linux, i.e., the Linux kernel itself rather than a specific subsystem package.