mm: fix list corruption in put_pages_list

My recent change to put_pages_list() dereferences folio->lru.next after
returning the folio to the page allocator.  Usually this is now on the pcp
list with other free folios, so we try to free an already-free folio. 
This only happens with lists that have more than 15 entries, so it wasn't
immediately discovered.  Revert to using list_for_each_safe() so we
dereference lru.next before disposing of the folio.

Link: https://lkml.kernel.org/r/[email protected]
Fixes: 24835f8 ("mm: use free_unref_folios() in put_pages_list()")
Signed-off-by: Matthew Wilcox (Oracle) <[email protected]>
Reported-by: "Borah, Chaitanya Kumar" <[email protected]>
Closes: https://lore.kernel.org/intel-gfx/SJ1PR11MB61292145F3B79DA58ADDDA63B9232@SJ1PR11MB6129.namprd11.prod.outlook.com/
Signed-off-by: Andrew Morton <[email protected]>

Author: Matthew Wilcox (Oracle)

mm/swap.c

@@ -152,10 +152,10 @@ EXPORT_SYMBOL(__folio_put);
 void put_pages_list(struct list_head *pages)
 {
 	struct folio_batch fbatch;
-	struct folio *folio;
+	struct folio *folio, *next;
 
 	folio_batch_init(&fbatch);
-	list_for_each_entry(folio, pages, lru) {
+	list_for_each_entry_safe(folio, next, pages, lru) {
 		if (!folio_put_testzero(folio))
 			continue;
 		if (folio_test_large(folio)) {