[bug report] dlm: add new configfs entry release_recover for lockspace members

[Dan Carpenter <dan.carpenter@linaro.org>]

Hello Alexander Aring,

Commit de7b4869b4ec ("dlm: add new configfs entry release_recover for
lockspace members") from Jul 23, 2025 (linux-next), leads to the
following Smatch static checker warning:

	fs/dlm/member.c:579 dlm_recover_members()
	error: we previously assumed 'node' could be null (see line 574)

fs/dlm/member.c
    551 int dlm_recover_members(struct dlm_ls *ls, struct dlm_recover *rv, int *neg_out)
    552 {
    553         struct dlm_member *memb, *safe;
    554         struct dlm_config_node *node;
    555         int i, error, neg = 0, low = -1;
    556         unsigned int release_recover;
    557 
    558         /* previously removed members that we've not finished removing need to
    559          * count as a negative change so the "neg" recovery steps will happen
    560          *
    561          * This functionality must report all member changes to lsops or
    562          * midcomms layer and must never return before.
    563          */
    564 
    565         list_for_each_entry(memb, &ls->ls_nodes_gone, list) {
    566                 log_rinfo(ls, "prev removed member %d", memb->nodeid);
    567                 neg++;
    568         }
    569 
    570         /* move departed members from ls_nodes to ls_nodes_gone */
    571 
    572         list_for_each_entry_safe(memb, safe, &ls->ls_nodes, list) {
    573                 node = find_config_node(rv, memb->nodeid);
    574                 if (node && !node->new && !node->gone)
                            ^^^^
So "node" can be NULL

    575                         continue;
    576 
    577                 release_recover = 0;
    578 
--> 579                 if (node->gone) {
                            ^^^^^^^^^^
unchecked dereference

    580                         release_recover = node->release_recover;
    581                         log_rinfo(ls, "remove member %d%s", memb->nodeid,
    582                                   release_recover ? " (release_recover)" : "");
    583                 } else {
    584                         /* removed and re-added */
    585                         log_rinfo(ls, "remove member %d comm_seq %u %u",
    586                                   memb->nodeid, memb->comm_seq, node->comm_seq);
    587                 }

regards,
dan carpenter