Hello Andrea Arcangeli,
The patch 1073fbb7013b: "ksm: introduce ksm_max_page_sharing per page
deduplication limit" from May 13, 2017, leads to the following static
checker warning:
mm/ksm.c:1442 __stable_node_chain()
warn: 'stable_node' was already freed.
mm/ksm.c
1433 static struct stable_node *__stable_node_chain(struct stable_node **_stable_node,
1434 struct page **tree_page,
1435 struct rb_root *root,
1436 bool prune_stale_stable_nodes)
1437 {
1438 struct stable_node *stable_node = *_stable_node;
1439 if (!is_stable_node_chain(stable_node)) {
1440 if (is_page_sharing_candidate(stable_node)) {
1441 *tree_page = get_ksm_page(stable_node, false);
1442 return stable_node;
There is a comment about this somewhere down the call tree but if
get_ksm_page() fails then we're returning a freed pointer here which is
gnarly.
1443 }
1444 return NULL;
1445 }
1446 return stable_node_dup(_stable_node, tree_page, root,
1447 prune_stale_stable_nodes);
1448 }
regards,
dan carpenter
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