Commit a7ba9f24 authored May 27, 2020 by Hugh Dickins Committed by Greg Kroah-Hartman Jun 03, 2020

mm,thp: stop leaking unreleased file pages



[ Upstream commit 2f33a706027c94cd4f70fcd3e3f4a17c1ce4ea4b ]

When collapse_file() calls try_to_release_page(), it has already isolated
the page: so if releasing buffers happens to fail (as it sometimes does),
remember to putback_lru_page(): otherwise that page is left unreclaimable
and unfreeable, and the file extent uncollapsible.

Fixes: 99cb0dbd ("mm,thp: add read-only THP support for (non-shmem) FS")
Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Song Liu <songliubraving@fb.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: <stable@vger.kernel.org>	[5.4+]
Link: http://lkml.kernel.org/r/alpine.LSU.2.11.2005231837500.1766@eggly.anvils


Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

parent 21358b3e

mm/khugepaged.c

+1 −0

Original line number	Diff line number	Diff line
		@@ -1655,6 +1655,7 @@ static void collapse_file(struct mm_struct *mm,
		if (page_has_private(page) &&
		!try_to_release_page(page, GFP_KERNEL)) {
		result = SCAN_PAGE_HAS_PRIVATE;
		putback_lru_page(page);
		goto out_unlock;
		}