Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 98ed2b00 authored by Naoya Horiguchi's avatar Naoya Horiguchi Committed by Linus Torvalds
Browse files

mm/memory-failure: give up error handling for non-tail-refcounted thp 



"non anonymous thp" case is still racy with freeing thp, which causes
panic due to put_page() for refcount-0 page.  It seems that closing up
this race might be hard (and/or not worth doing,) so let's give up the
error handling for this case.

Signed-off-by: default avatarNaoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Dean Nelson <dnelson@redhat.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Hugh Dickins <hughd@google.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent a209ef09

mm/memory-failure.c

+12 −9
Original line number Diff line number Diff line
@@ -909,6 +909,18 @@ int get_hwpoison_page(struct page *page) 
	 * directly for tail pages.

	 */

	if (PageTransHuge(head)) {

		/*

		 * Non anonymous thp exists only in allocation/free time. We

		 * can't handle such a case correctly, so let's give it up.

		 * This should be better than triggering BUG_ON when kernel

		 * tries to touch the "partially handled" page.

		 */

		if (!PageAnon(head)) {

			pr_err("MCE: %#lx: non anonymous thp\n",

				page_to_pfn(page));

			return 0;

		}



		if (get_page_unless_zero(head)) {

			if (PageTail(page))

				get_page(page);
@@ -1134,15 +1146,6 @@ int memory_failure(unsigned long pfn, int trapno, int flags) 
	}



	if (!PageHuge(p) && PageTransHuge(hpage)) {

		if (!PageAnon(hpage)) {

			pr_err("MCE: %#lx: non anonymous thp\n", pfn);

			if (TestClearPageHWPoison(p))

				atomic_long_sub(nr_pages, &num_poisoned_pages);

			put_page(p);

			if (p != hpage)

				put_page(hpage);

			return -EBUSY;

		}

		if (unlikely(split_huge_page(hpage))) {

			pr_err("MCE: %#lx: thp split failed\n", pfn);

			if (TestClearPageHWPoison(p))