CVE-2026-89548SUNRPC: always drain cache_cleaner before destroying a cache_detail

Official description

In the Linux kernel, the following vulnerability has been resolved: SUNRPC: always drain cache_cleaner before destroying a cache_detail sunrpc_destroy_cache_detail() only cancels the global cache_cleaner delayed_work when cache_list is empty. During per-netns teardown cache_list is never empty because init_net's caches remain registered, so the cancel never fires. After unlink, the caller proceeds to cache_destroy_net() which kfrees the cache_detail while cache_clean() may still hold a dangling pointer to it. The result is a use-after-free: cache_dequeue() takes cd->queue_lock on freed memory, and cache_put() dereferences cd->cache_put as a function pointer from freed slab. Drop the list_empty guard so that cancel_delayed_work_sync() always runs, ensuring any in-flight cache_clean() completes before the cache_detail is freed. Re-arm the cleaner afterwards if other caches are still registered.

Affected packages & fixed versions

Affected products (as reported)

References

• https://git.kernel.org/stable/c/dec787a15c96a5665e9ffc61b429a6a4ab26e6b9
• https://git.kernel.org/stable/c/5eea874a696201c31e7c2d7badbfa0d90e9961b5
• https://git.kernel.org/stable/c/cf239de7fdcc8336259b01ea4bcf650dadad1040
• https://git.kernel.org/stable/c/6d74ecc2be120a0c300b224b7649fe93c0453714
• https://git.kernel.org/stable/c/9d44836f60c8c29bcdb1471fd9202387c642a890
• https://git.kernel.org/stable/c/2e861ce2aaa468351a6a47c4cbb4971ebb740c7b
• https://git.kernel.org/stable/c/3d60fdf951143d6ef4e352e2f8eb852286701726
• https://git.kernel.org/stable/c/f42d0fda0c67695db6bc704b04b7c10240805377