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

From: Souptick Joarder
Date: Tue Jul 12 2022 - 22:41:22 EST


From: "Souptick Joarder (HPE)" <jrdr.linux@xxxxxxxxx>

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

Avoiding possible memory leak.

Reported-by: kernel test robot <lkp@xxxxxxxxx>
Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
Signed-off-by: Souptick Joarder (HPE) <jrdr.linux@xxxxxxxxx>
---
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