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From:   Souptick Joarder <jrdr.linux@gmail.com>
To:     akpm@linux-foundation.org
Cc:     linux-mm@kvack.org, linux-kernel@vger.kernel.org,
        "Souptick Joarder (HPE)" <jrdr.linux@gmail.com>,
        kernel test robot <lkp@intel.com>,
        Dan Carpenter <dan.carpenter@oracle.com>
Subject: [PATCH] mm/khugepaged: Avoid possible memory leak in failure path
Date:   Wed, 13 Jul 2022 08:11:09 +0530
Message-Id: <20220713024109.62810-1-jrdr.linux@gmail.com>
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From: "Souptick Joarder (HPE)" <jrdr.linux@gmail.com>

smatch warnings:
mm/khugepaged.c:2409 madvise_collapse() warn: possible memory
leak of 'cc'

Avoiding possible memory leak.

Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Souptick Joarder (HPE) <jrdr.linux@gmail.com>
---
 mm/khugepaged.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/mm/khugepaged.c b/mm/khugepaged.c
index 0207fc0a5b2a..8da9e7467543 100644
--- a/mm/khugepaged.c
+++ b/mm/khugepaged.c
@@ -2397,12 +2397,6 @@ int madvise_collapse(struct vm_area_struct *vma, struct vm_area_struct **prev,
 	BUG_ON(vma->vm_start > start);
 	BUG_ON(vma->vm_end < end);
 
-	cc = kmalloc(sizeof(*cc), GFP_KERNEL);
-	if (!cc)
-		return -ENOMEM;
-	cc->is_khugepaged = false;
-	cc->last_target_node = NUMA_NO_NODE;
-
 	*prev = vma;
 
 	/* TODO: Support file/shmem */
@@ -2415,6 +2409,12 @@ int madvise_collapse(struct vm_area_struct *vma, struct vm_area_struct **prev,
 	if (!hugepage_vma_check(vma, vma->vm_flags, false, false, false))
 		return -EINVAL;
 
+	cc = kmalloc(sizeof(*cc), GFP_KERNEL);
+	if (!cc)
+		return -ENOMEM;
+	cc->is_khugepaged = false;
+	cc->last_target_node = NUMA_NO_NODE;
+
 	mmgrab(mm);
 	lru_add_drain_all();
 
-- 
2.25.1