linux-kernel - [PATCH v3 11/13 fix] mm/khugepaged: delete khugepaged_collapse_pte_mapped

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Message-ID: <bfc6cab2-497f-32bf-dd5-98dc1987e4a9@google.com>
Date:   Sun, 23 Jul 2023 15:35:07 -0700 (PDT)
From:   Hugh Dickins <hughd@...gle.com>
To:     Andrew Morton <akpm@...ux-foundation.org>
cc:     Mike Kravetz <mike.kravetz@...cle.com>,
        Mike Rapoport <rppt@...nel.org>,
        "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>,
        Matthew Wilcox <willy@...radead.org>,
        David Hildenbrand <david@...hat.com>,
        Suren Baghdasaryan <surenb@...gle.com>,
        Qi Zheng <zhengqi.arch@...edance.com>,
        Yang Shi <shy828301@...il.com>,
        Mel Gorman <mgorman@...hsingularity.net>,
        Peter Xu <peterx@...hat.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Will Deacon <will@...nel.org>, Yu Zhao <yuzhao@...gle.com>,
        Alistair Popple <apopple@...dia.com>,
        Ralph Campbell <rcampbell@...dia.com>,
        Ira Weiny <ira.weiny@...el.com>,
        Steven Price <steven.price@....com>,
        SeongJae Park <sj@...nel.org>,
        Lorenzo Stoakes <lstoakes@...il.com>,
        Huang Ying <ying.huang@...el.com>,
        Naoya Horiguchi <naoya.horiguchi@....com>,
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        Vlastimil Babka <vbabka@...e.cz>, Zi Yan <ziy@...dia.com>,
        linux-arm-kernel@...ts.infradead.org, sparclinux@...r.kernel.org,
        linuxppc-dev@...ts.ozlabs.org, linux-s390@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-mm@...ck.org
Subject: [PATCH v3 11/13 fix] mm/khugepaged: delete khugepaged_collapse_pte_mapped_thps():
 fix

Though not yet detected by syzbot, this commit was making the same
mistake with mmap_locked as the previous commit: fix that.

Signed-off-by: Hugh Dickins <hughd@...gle.com>
---
 mm/khugepaged.c | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/mm/khugepaged.c b/mm/khugepaged.c
index 1c773db26e88..41913730db4c 100644
--- a/mm/khugepaged.c
+++ b/mm/khugepaged.c
@@ -2380,19 +2380,17 @@ static unsigned int khugepaged_scan_mm_slot(unsigned int pages, int *result,
 				mmap_locked = false;
 				*result = hpage_collapse_scan_file(mm,
 					khugepaged_scan.address, file, pgoff, cc);
+				fput(file);
 				if (*result == SCAN_PTE_MAPPED_HUGEPAGE) {
 					mmap_read_lock(mm);
-					mmap_locked = true;
-					if (hpage_collapse_test_exit(mm)) {
-						fput(file);
+					if (hpage_collapse_test_exit(mm))
 						goto breakouterloop;
-					}
 					*result = collapse_pte_mapped_thp(mm,
 						khugepaged_scan.address, false);
 					if (*result == SCAN_PMD_MAPPED)
 						*result = SCAN_SUCCEED;
+					mmap_read_unlock(mm);
 				}
-				fput(file);
 			} else {
 				*result = hpage_collapse_scan_pmd(mm, vma,
 					khugepaged_scan.address, &mmap_locked, cc);
-- 
2.35.3