Re: [PATCH 1/1] DSPBRIDGE: cache operation against kernel address instead of user's

[Felipe Contreras <felipe.contreras@xxxxxxxxx>]

Hi,

While investigating a bug in maemo[1] I found that this patch triggers
it, I think I found the reason.

It probably doesn't matter for upstream anymore.

On Fri, Nov 6, 2009 at 3:34 PM, Hiroshi DOYU <Hiroshi.DOYU@xxxxxxxxx> wrote:
> @@ -690,14 +732,19 @@ static int memory_check_vma(unsigned long start, u32 len)
>        if (end <= start)
>                return -EINVAL;
>
> -       down_read(&current->mm->mmap_sem);
> -
>        while ((vma = find_vma(current->mm, start)) != NULL) {
> +               ssize_t size;
>
> -               if (vma->vm_start > start) {
> -                       err = -EINVAL;
> +               if (vma->vm_flags & (VM_IO | VM_PFNMAP))
> +                       return -EINVAL;
> +
> +               if (vma->vm_start > start)
> +                       return -EINVAL;
> +
> +               size = min_t(ssize_t, vma->vm_end - start, len);

This 'len' is the total length, which is not what we want; in each
iteration the length should be decreased so that it's always the
remaining length. Right?

len -= size;

> +               err = memory_sync_page(vma, start, size, ftype);
> +               if (err)
>                        break;
> -               }
>
>                if (end <= vma->vm_end)
>                        break;

[1] https://bugs.maemo.org/show_bug.cgi?id=10813

-- 
Felipe Contreras
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