[PATCH v2] mm: fix the memory leak after collapsing the huge page fails

[zhongjiang <zhongjiang@huawei.com>]

From: zhong jiang <zhongjiang@huawei.com>

Current, when we prepare a huge page to collapse, due to some
reasons, it can fail to collapse. At the moment, we should
release the preallocate huge page.

Signed-off-by: zhong jiang <zhongjiang@huawei.com>
---
 mm/khugepaged.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/mm/khugepaged.c b/mm/khugepaged.c
index 7cb9c88..586b1f1 100644
--- a/mm/khugepaged.c
+++ b/mm/khugepaged.c
@@ -1082,6 +1082,8 @@ static void collapse_huge_page(struct mm_struct *mm,
 	up_write(&mm->mmap_sem);
 out_nolock:
 	trace_mm_collapse_huge_page(mm, isolated, result);
+	if (page != NULL && result != SCAN_SUCCEED)
+		put_page(new_page);
 	return;
 out:
 	mem_cgroup_cancel_charge(new_page, memcg, true);
@@ -1555,6 +1557,8 @@ static void collapse_shmem(struct mm_struct *mm,
 	}
 out:
 	VM_BUG_ON(!list_empty(&pagelist));
+	if (page != NULL && result != SCAN_SUCCEED)
+		put_page(new_page);
 	/* TODO: tracepoints */
 }
 
-- 
1.8.3.1

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