VisionFive2 Linux kernel

StarFive Tech Linux Kernel for VisionFive (JH7110) boards (mirror)

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author: Yang Shi <shy828301@gmail.com> 2021-10-28 14:36:11 -0700 committer: Linus Torvalds <torvalds@linux-foundation.org> 2021-10-28 17:18:55 -0700 commit: eac96c3efdb593df1a57bb5b95dbe037bfa9a522 parent: c7cb42e94473aafe553c0f2a3d8ca904599399ed
Commit Summary:
mm: filemap: check if THP has hwpoisoned subpage for PMD page fault
Diffstat:
4 files changed, 28 insertions, 1 deletion
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 92192cb086c7..c5142d237e48 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -2426,6 +2426,8 @@ static void __split_huge_page(struct page *page, struct list_head *list,
 	/* lock lru list/PageCompound, ref frozen by page_ref_freeze */
 	lruvec = lock_page_lruvec(head);
 
+	ClearPageHasHWPoisoned(head);
+
 	for (i = nr - 1; i >= 1; i--) {
 		__split_huge_page_tail(head, i, lruvec, list);
 		/* Some pages can be beyond EOF: drop them from page cache */
diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index 73f68699e7ab..bdbbb32211a5 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -1694,6 +1694,20 @@ try_again:
 	}
 
 	if (PageTransHuge(hpage)) {
+		/*
+		 * The flag must be set after the refcount is bumped
+		 * otherwise it may race with THP split.
+		 * And the flag can't be set in get_hwpoison_page() since
+		 * it is called by soft offline too and it is just called
+		 * for !MF_COUNT_INCREASE.  So here seems to be the best
+		 * place.
+		 *
+		 * Don't need care about the above error handling paths for
+		 * get_hwpoison_page() since they handle either free page
+		 * or unhandlable page.  The refcount is bumped iff the
+		 * page is a valid handlable page.
+		 */
+		SetPageHasHWPoisoned(hpage);
 		if (try_to_split_thp_page(p, "Memory Failure") < 0) {
 			action_result(pfn, MF_MSG_UNSPLIT_THP, MF_IGNORED);
 			res = -EBUSY;
diff --git a/mm/memory.c b/mm/memory.c
index adf9b9ef8277..c52be6d6b605 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -3906,6 +3906,15 @@ vm_fault_t do_set_pmd(struct vm_fault *vmf, struct page *page)
 	if (compound_order(page) != HPAGE_PMD_ORDER)
 		return ret;
 
+	/*
+	 * Just backoff if any subpage of a THP is corrupted otherwise
+	 * the corrupted page may mapped by PMD silently to escape the
+	 * check.  This kind of THP just can be PTE mapped.  Access to
+	 * the corrupted subpage should trigger SIGBUS as expected.
+	 */
+	if (unlikely(PageHasHWPoisoned(page)))
+		return ret;
+
 	/*
 	 * Archs like ppc64 need additional space to store information
 	 * related to pte entry. Use the preallocated table for that.
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 3ec39552d00f..23d3339ac4e8 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1312,8 +1312,10 @@ static __always_inline bool free_pages_prepare(struct page *page,
 
 		VM_BUG_ON_PAGE(compound && compound_order(page) != order, page);
 
-		if (compound)
+		if (compound) {
 			ClearPageDoubleMap(page);
+			ClearPageHasHWPoisoned(page);
+		}
 		for (i = 1; i < (1 << order); i++) {
 			if (compound)
 				bad += free_tail_pages_check(page, page + i);