CyberRota Analysis
AI-GeneratedThe vulnerability affects the Linux kernel's NFS daemon (nfsd), where a race condition exists between the file cache management and network shutdown processes, potentially leading to resource leaks. Specifically, if the file cache is being cleaned up while files are being disposed of, it can result in files remaining in the disposal list without being processed, causing memory leaks and associated state retention. System administrators and developers managing Linux environments, particularly those utilizing NFS, should prioritize this issue to ensure system stability and resource management.
Original NVD Description
In the Linux kernel, the following vulnerability has been resolved: nfsd: close shrinker/GC/fsnotify vs per-net shutdown race in filecache The shrinker, GC worker, and fsnotify/lease callbacks can unhash an nfsd_file from the rhashtable and then call nfsd_file_dispose_list_delayed() to move it to the per-net dispose list. If nfsd_file_cache_shutdown_net() runs concurrently, its rhashtable walk misses the already-unhashed file, and its drain of the per-net dispose list can run before the file has been queued. The file then sits on the per-net list with no thread to drain it, leaking both the file and its associated state. The GC worker and shrinker already hold nfsd_gc_lock while walking the LRU, but in the original code they release it before calling nfsd_file_dispose_list_delayed(). The fsnotify/lease path (nfsd_file_close_inode) has no synchronization at all. Fix this by: 1. Widening nfsd_gc_lock in both nfsd_file_gc() and nfsd_file_lru_scan() to cover the nfsd_file_dispose_list_delayed() call. 2. Wrapping nfsd_file_close_inode() in nfsd_gc_lock so that all three callers of nfsd_file_dispose_list_delayed() hold the lock. 3. Adding a spin_lock/unlock(nfsd_gc_lock) barrier in nfsd_file_cache_shutdown_net() after the purge, so that any in-progress disposal has fully completed before the per-net list is drained. All operations inside the lock are non-sleeping (rhashtable lookups, atomic bit/refcount ops, list moves, svc_wake_up), so the spinlock is appropriate.