[LU-9919] unsafe peer access in lnet_select_pathway()

• Type: Bug
• Resolution: Fixed
• Priority: Minor
• Fix Version/s: Lustre 2.11.0
• Severity: 3
• Assignee: Amir Shehata (Inactive)
• Reporter: John Hammond

Description

Looking at the changes to lnet_select_pathway() in https://review.whamcloud.com/#/c/25789/24/lnet/lnet/lib-move.c the accesses to peer appear to be unsafe. In the CDEBUG() peer may be invalid:

                lnet_peer_ni_decref_locked(lpni);
                lnet_net_unlock(cpt);

                CDEBUG(D_NET, "%s pending discovery\n",
                       libcfs_nid2str(peer->lp_primary_nid));

                return LNET_DC_WAIT;

And similarly after the lpni has been released:

        }
        lnet_peer_ni_decref_locked(lpni);

        /* If peer is not healthy then can not send anything to it */
        if (!lnet_is_peer_healthy_locked(peer)) {
                lnet_net_unlock(cpt);
                return -EHOSTUNREACH;
        }