Commit d51b6846 authored Jul 01, 2023 by Miaohe Lin Committed by Andrew Morton Aug 24, 2023

mm: memory-failure: fix potential page refcnt leak in memory_failure()

put_ref_page() is not called to drop extra refcnt when comes from madvise
in the case pfn is valid but pgmap is NULL leading to page refcnt leak.

Link: https://lkml.kernel.org/r/20230701072837.1994253-1-linmiaohe@huawei.com

Fixes: 1e8aaedb ("mm,memory_failure: always pin the page in madvise_inject_error")
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Acked-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

parent 08dff281

mm/memory-failure.c

+1 −2

Original line number	Diff line number	Diff line
		@@ -2117,8 +2117,6 @@ static int memory_failure_dev_pagemap(unsigned long pfn, int flags,
		{
		int rc = -ENXIO;

		put_ref_page(pfn, flags);

		/* device metadata space is not recoverable */
		if (!pgmap_pfn_valid(pgmap, pfn))
		goto out;
		@@ -2193,6 +2191,7 @@ int memory_failure(unsigned long pfn, int flags)

		if (pfn_valid(pfn)) {
		pgmap = get_dev_pagemap(pfn, NULL);
		put_ref_page(pfn, flags);
		if (pgmap) {
		res = memory_failure_dev_pagemap(pfn, flags,
		pgmap);