Re: [PATCH v2 3/7] mm/gup: remove vmas parameter from get_user_pages_remote()

[Lorenzo Stoakes]

On Sat, Apr 15, 2023 at 06:52:41PM +0900, Tetsuo Handa wrote:
> On 2023/04/15 18:08, Lorenzo Stoakes wrote:
> > @@ -475,10 +474,14 @@ int uprobe_write_opcode(struct arch_uprobe *auprobe, struct mm_struct *mm,
> >  		gup_flags |= FOLL_SPLIT_PMD;
> >  	/* Read the page with vaddr into memory */
> >  	ret = get_user_pages_remote(mm, vaddr, 1, gup_flags,
> > -				    &old_page, &vma, NULL);
> > +				    &old_page, NULL);
> >  	if (ret <= 0)
> >  		return ret;
> >
> > +	vma = vma_lookup(mm, vaddr);
> > +	if (!vma)
> > +		goto put_old;
> > +
> >  	ret = verify_opcode(old_page, vaddr, &opcode);
> >  	if (ret <= 0)
> >  		goto put_old;
>
> This conversion looks wrong.
> This causes returning a positive number when vma_lookup() returned NULL.
>
>   * Return 0 (success) or a negative errno.
>

In reality it shouldn't be possible for vma to return NULL, I'm adding the
checks to be extra careful.

In any case you're right, attaching a -fix patch to avoid spam:-

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