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

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

mm/swap.c

+2 −2
Original line number Diff line number Diff line
@@ -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)) {