In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
nfsd: close shrinker\/GC\/fsnotify vs per-net shutdown race in filecache<\/p>\n
The shrinker, GC worker, and fsnotify\/lease callbacks can unhash an
\nnfsd_file from the rhashtable and then call
\nnfsd_file_dispose_list_delayed() to move it to the per-net dispose list.
\nIf nfsd_file_cache_shutdown_net() runs concurrently, its rhashtable walk
\nmisses the already-unhashed file, and its drain of the per-net dispose
\nlist can run before the file has been queued. The file then sits on
\nthe per-net list with no thread to drain it, leaking both the file and
\nits associated state.<\/p>\n
The GC worker and shrinker already hold nfsd_gc_lock while walking the
\nLRU, but in the original code they release it before calling
\nnfsd_file_dispose_list_delayed(). The fsnotify\/lease path
\n(nfsd_file_close_inode) has no synchronization at all.<\/p>\n
Fix this by:<\/p>\n
1. Widening nfsd_gc_lock in both nfsd_file_gc() and nfsd_file_lru_scan()
\n to cover the nfsd_file_dispose_list_delayed() call.<\/p>\n
2. Wrapping nfsd_file_close_inode() in nfsd_gc_lock so that all three
\n callers of nfsd_file_dispose_list_delayed() hold the lock.<\/p>\n
3. Adding a spin_lock\/unlock(nfsd_gc_lock) barrier in
\n nfsd_file_cache_shutdown_net() after the purge, so that any
\n in-progress disposal has fully completed before the per-net list
\n is drained.<\/p>\n
All operations inside the lock are non-sleeping (rhashtable lookups,
\natomic bit\/refcount ops, list moves, svc_wake_up), so the spinlock is
\nappropriate.<\/p>\n","protected":false},"excerpt":{"rendered":"
In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
nfsd: close shrinker\/GC\/fsnotify vs per-net shutdown race in filecache<\/p>\n
The shrinker, GC worker, and fsnotify\/lease callbacks can u<\/p>\n","protected":false},"template":"","meta":[],"categories":[],"tags":[],"class_list":["post-21589","vuln","type-vuln","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln\/21589","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln"}],"about":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/types\/vuln"}],"wp:attachment":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=21589"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=21589"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=21589"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}