Merge tag 'mm-hotfixes-stable-2023-08-11-13-44' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull misc fixes from Andrew Morton:
 "14 hotfixes. 11 of these are cc:stable and the remainder address
  post-6.4 issues, or are not considered suitable for -stable
  backporting"

* tag 'mm-hotfixes-stable-2023-08-11-13-44' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm:
  mm/damon/core: initialize damo_filter->list from damos_new_filter()
  nilfs2: fix use-after-free of nilfs_root in dirtying inodes via iput
  selftests: cgroup: fix test_kmem_basic false positives
  fs/proc/kcore: reinstate bounce buffer for KCORE_TEXT regions
  MAINTAINERS: add maple tree mailing list
  mm: compaction: fix endless looping over same migrate block
  selftests: mm: ksm: fix incorrect evaluation of parameter
  hugetlb: do not clear hugetlb dtor until allocating vmemmap
  mm: memory-failure: avoid false hwpoison page mapped error info
  mm: memory-failure: fix potential unexpected return value from unpoison_memory()
  mm/swapfile: fix wrong swap entry type for hwpoisoned swapcache page
  radix tree test suite: fix incorrect allocation size for pthreads
  crypto, cifs: fix error handling in extract_iter_to_sg()
  zsmalloc: fix races between modifications of fullness and isolated

1 files changed, 16 insertions, 13 deletions

diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index ece5d481b5ff..9a285038d765 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -2466,7 +2466,7 @@ int unpoison_memory(unsigned long pfn)
 {
 	struct folio *folio;
 	struct page *p;
-	int ret = -EBUSY;
+	int ret = -EBUSY, ghp;
 	unsigned long count = 1;
 	bool huge = false;
 	static DEFINE_RATELIMIT_STATE(unpoison_rs, DEFAULT_RATELIMIT_INTERVAL,
@@ -2499,6 +2499,13 @@ int unpoison_memory(unsigned long pfn)
 		goto unlock_mutex;
 	}
 
+	if (folio_test_slab(folio) || PageTable(&folio->page) || folio_test_reserved(folio))
+		goto unlock_mutex;
+
+	/*
+	 * Note that folio->_mapcount is overloaded in SLAB, so the simple test
+	 * in folio_mapped() has to be done after folio_test_slab() is checked.
+	 */
 	if (folio_mapped(folio)) {
 		unpoison_pr_info("Unpoison: Someone maps the hwpoison page %#lx\n",
 				 pfn, &unpoison_rs);
@@ -2511,32 +2518,28 @@ int unpoison_memory(unsigned long pfn)
 		goto unlock_mutex;
 	}
 
-	if (folio_test_slab(folio) || PageTable(&folio->page) || folio_test_reserved(folio))
-		goto unlock_mutex;
-
-	ret = get_hwpoison_page(p, MF_UNPOISON);
-	if (!ret) {
+	ghp = get_hwpoison_page(p, MF_UNPOISON);
+	if (!ghp) {
 		if (PageHuge(p)) {
 			huge = true;
 			count = folio_free_raw_hwp(folio, false);
-			if (count == 0) {
-				ret = -EBUSY;
+			if (count == 0)
 				goto unlock_mutex;
-			}
 		}
 		ret = folio_test_clear_hwpoison(folio) ? 0 : -EBUSY;
-	} else if (ret < 0) {
-		if (ret == -EHWPOISON) {
+	} else if (ghp < 0) {
+		if (ghp == -EHWPOISON) {
 			ret = put_page_back_buddy(p) ? 0 : -EBUSY;
-		} else
+		} else {
+			ret = ghp;
 			unpoison_pr_info("Unpoison: failed to grab page %#lx\n",
 					 pfn, &unpoison_rs);
+		}
 	} else {
 		if (PageHuge(p)) {
 			huge = true;
 			count = folio_free_raw_hwp(folio, false);
 			if (count == 0) {
-				ret = -EBUSY;
 				folio_put(folio);
 				goto unlock_mutex;
 			}