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mm/khugepaged: Avoid possible memory leak in failure path

PATCH In review Souptick Joarder 2 participants 2 messages Jul 13, 2022

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#0 lore raw

PATCH 1/1 mm/khugepaged: Avoid possible memory leak in failure path

From: "Souptick Joarder (HPE)" <[email protected]>

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

Avoiding possible memory leak.

---
 mm/khugepaged.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)
mm/khugepaged.c +6 -6
index 0207fc0a5b2a..8da9e7467543 100644
@@ -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();
 
Signature · 1 line
2.25.1
#1 lore raw
Quoted 49 lines · Souptick Joarder

From: "Souptick Joarder (HPE)" <[email protected]>

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

Avoiding possible memory leak.

---
 mm/khugepaged.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)
mm/khugepaged.c +6 -6
index 0207fc0a5b2a..8da9e7467543 100644
@@ -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();
 
Signature · 1 line
2.25.1

Thanks for the fix!

I've also sent out another patch on top which addresses the actual missing kfree()