Wind River Support Network

Description

In the Linux kernel, the following vulnerability has been resolved:  NFSD: Prevent client use-after-free during export state revocation  nfsd4_revoke_export_states() has the same use-after-free as nfsd4_revoke_states(): it drops nn->client_lock across revoke_one_stid() and the following read of clp->cl_minorversion, but the stateid reference it holds does not pin the client.  A teardown racing the dropped lock can free the client while revoke_one_stid() still dereferences it.  exportfs -u drives this path through NFSD_CMD_UNLOCK_EXPORT, so an administrator removing an export can race a client expiry.  Skip a client that is already expiring and otherwise pin it with cl_rpc_users under client_lock before dropping the lock, matching nfsd4_revoke_states().