CVE-2026-89798rpcrdma: arm rn_done before publishing the notification

Official description

In the Linux kernel, the following vulnerability has been resolved: rpcrdma: arm rn_done before publishing the notification rpcrdma_rn_register() inserts @rn into rd_xa with xa_alloc() before storing the caller's callback in rn->rn_done. The xarray makes @rn reachable to rpcrdma_remove_one(), which walks rd_xa and invokes rn->rn_done(rn) for every registered notification. A device removal that races a fresh registration can therefore observe @rn with rn_done still NULL, because the notification objects are zero allocated by their owners, and call through a NULL function pointer. Store rn->rn_done before xa_alloc() publishes @rn. The xarray's store-side and load-side ordering then guarantees that any CPU which finds @rn in rd_xa also observes the armed callback. rpcrdma_rn_unregister() treats a non-NULL rn_done as the sentinel for a completed registration, so the early store must not survive a failed registration. Clear rn_done again when xa_alloc() fails. Were it left set, the failed-accept cleanup path would call rpcrdma_rn_unregister() on an @rn that was never inserted, erasing an unrelated rd_xa slot and underflowing rd_kref.

Affected packages & fixed versions

Affected products (as reported)

References

• https://git.kernel.org/stable/c/f9fe3cad43c42d874a388583552b39b411d886eb
• https://git.kernel.org/stable/c/3c97b8e76ca2bba9e8770571413aed694068e78e
• https://git.kernel.org/stable/c/ea0408273ccf5df1fb52d9a1b9db4d31600dcb36
• https://git.kernel.org/stable/c/5b06f706374c37375bdff9d21cc10e61df925a92