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

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

[Souptick Joarder]

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

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

[Zach O'Keefe]

On Jul 13 08:11, Souptick Joarder wrote:
> 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
> 
> 

Thanks for the fix!

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