Commit b555895c authored by Matthew Wilcox (Oracle)'s avatar Matthew Wilcox (Oracle) Committed by Andrew Morton

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/20240306212749.1823380-1-willy@infradead.org
Fixes: 24835f89 ("mm: use free_unref_folios() in put_pages_list()")
Signed-off-by: default avatarMatthew Wilcox (Oracle) <willy@infradead.org>
Reported-by: default avatar"Borah, Chaitanya Kumar" <chaitanya.kumar.borah@intel.com>
Closes: https://lore.kernel.org/intel-gfx/SJ1PR11MB61292145F3B79DA58ADDDA63B9232@SJ1PR11MB6129.namprd11.prod.outlook.com/Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 47932e70
......@@ -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)) {
......
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