Thanks. This is a valid issue and a good fix.
Reviewed-by: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx>
* Yang Yingliang <yangyingliang@xxxxxxxxxx> [220824 00:16]:
> The memory allocated before calling mas_preallocate() is leaked if it fails.
> 'mas' won't be modify until calling mas_preallocate(), so move it up and
> add error label for free the memory.
>
> Fixes: 8aff7dbeaeb1 ("nommu: remove uses of VMA linked list")
> Signed-off-by: Yang Yingliang <yangyingliang@xxxxxxxxxx>
> ---
> mm/nommu.c | 21 +++++++++++++--------
> 1 file changed, 13 insertions(+), 8 deletions(-)
>
> diff --git a/mm/nommu.c b/mm/nommu.c
> index 6c611a689ec0..214c70e1d059 100644
> --- a/mm/nommu.c
> +++ b/mm/nommu.c
> @@ -1355,9 +1355,13 @@ int split_vma(struct mm_struct *mm, struct vm_area_struct *vma,
> return -ENOMEM;
>
> new = vm_area_dup(vma);
> - if (!new) {
> - kmem_cache_free(vm_region_jar, region);
> - return -ENOMEM;
> + if (!new)
> + goto err_vma_dup;
> +
> + if (mas_preallocate(&mas, vma, GFP_KERNEL)) {
> + pr_warn("Allocation of vma tree for process %d failed\n",
> + current->pid);
> + goto err_mas_preallocate;
> }
>
> /* most fields are the same, copy all, and then fixup */
> @@ -1388,11 +1392,6 @@ int split_vma(struct mm_struct *mm, struct vm_area_struct *vma,
> add_nommu_region(vma->vm_region);
> add_nommu_region(new->vm_region);
> up_write(&nommu_region_sem);
> - if (mas_preallocate(&mas, vma, GFP_KERNEL)) {
> - pr_warn("Allocation of vma tree for process %d failed\n",
> - current->pid);
> - return -ENOMEM;
> - }
>
> setup_vma_to_mm(vma, mm);
> setup_vma_to_mm(new, mm);
> @@ -1400,6 +1399,12 @@ int split_vma(struct mm_struct *mm, struct vm_area_struct *vma,
> mas_store(&mas, vma);
> vma_mas_store(new, &mas);
> return 0;
> +
> +err_mas_preallocate:
> + vm_area_free(new);
> +err_vma_dup:
> + kmem_cache_free(vm_region_jar, region);
> + return -ENOMEM;
> }
>
> /*
> --
> 2.25.1
>
