[PATCH] powerpc/book3s64: Fix error handling in mm_iommu_do_alloc()

[Jan Kara]

On Fri 20-12-19 16:06:05, Alexey Kardashevskiy wrote:
> 
> 
> On 11/12/2019 21:42, Jan Kara wrote:
> > The last jump to free_exit in mm_iommu_do_alloc() happens after page
> > pointers in struct mm_iommu_table_group_mem_t were already converted to
> > physical addresses. Thus calling put_page() on these physical addresses
> > will likely crash. Convert physical addresses back to page pointers
> > during the error cleanup.
> > 
> > Signed-off-by: Jan Kara <jack at suse.cz>
> > ---
> >  arch/powerpc/mm/book3s64/iommu_api.c | 5 ++++-
> >  1 file changed, 4 insertions(+), 1 deletion(-)
> > 
> >  Beware, this is completely untested, spotted just by code audit.
> > 
> > diff --git a/arch/powerpc/mm/book3s64/iommu_api.c b/arch/powerpc/mm/book3s64/iommu_api.c
> > index 56cc84520577..06c403381c9c 100644
> > --- a/arch/powerpc/mm/book3s64/iommu_api.c
> > +++ b/arch/powerpc/mm/book3s64/iommu_api.c
> > @@ -154,7 +154,7 @@ static long mm_iommu_do_alloc(struct mm_struct *mm, unsigned long ua,
> >  				       (mem2->entries << PAGE_SHIFT)))) {
> >  			ret = -EINVAL;
> >  			mutex_unlock(&mem_list_mutex);
> > -			goto free_exit;
> > +			goto convert_exit;
> >  		}
> >  	}
> >  
> > @@ -166,6 +166,9 @@ static long mm_iommu_do_alloc(struct mm_struct *mm, unsigned long ua,
> >  
> >  	return 0;
> >  
> > +convert_exit:
> > +	for (i = 0; i < pinned; i++)
> > +		mem->hpages[i] = pfn_to_page(mem->hpas[i] >> PAGE_SHIFT);
> 
> 
> Good find. Although doing it where you added "goto convert_exit" seems
> cleaner imho. Thanks,

I don't really care :). V2 attached.

								Honza
-- 
Jan Kara <jack at suse.com>
SUSE Labs, CR
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