| Message ID | 20250116025005.55846-1-liuye@kylinos.cn (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | mm/vma: Add VM_WARN_ON for commit_merge | expand |
On Thu, 16 Jan 2025 10:50:05 +0800 Liu Ye <liuye@kylinos.cn> wrote: > Add VM_WARN_ON to prevent 'adjust' from accessing NULL pointers > when 'adjust' is NULL and 'expanded' is false or 'adj_start' is > not zero. > > ... > > --- a/mm/vma.c > +++ b/mm/vma.c > @@ -641,6 +641,7 @@ static int commit_merge(struct vma_merge_struct *vmg, > > init_multi_vma_prep(&vp, vmg->vma, adjust, remove, remove2); > > + VM_WARN_ON(!adjust && (!expanded || adj_start)); > VM_WARN_ON(vp.anon_vma && adjust && adjust->anon_vma && > vp.anon_vma != adjust->anon_vma); > This won't prevent a null deref. It will emit a warning which duplicates all the information which we're about to emit from the oops handler. Are there any reports of an oops from a NULL deref of `adjust'?
diff --git a/mm/vma.c b/mm/vma.c index 31c9c6f51c9f..36b5ac675504 100644 --- a/mm/vma.c +++ b/mm/vma.c @@ -641,6 +641,7 @@ static int commit_merge(struct vma_merge_struct *vmg, init_multi_vma_prep(&vp, vmg->vma, adjust, remove, remove2); + VM_WARN_ON(!adjust && (!expanded || adj_start)); VM_WARN_ON(vp.anon_vma && adjust && adjust->anon_vma && vp.anon_vma != adjust->anon_vma);
Add VM_WARN_ON to prevent 'adjust' from accessing NULL pointers when 'adjust' is NULL and 'expanded' is false or 'adj_start' is not zero. Signed-off-by: Liu Ye <liuye@kylinos.cn> --- mm/vma.c | 1 + 1 file changed, 1 insertion(+)