On 20/12/2019 20:57, Jan Kara wrote:

On Fri 20-12-19 16:06:05, Alexey Kardashevskiy wrote:

quoted

On 11/12/2019 21:42, Jan Kara wrote:

quoted

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@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.

Usually patches are posted using git send-mail, not as attachment. A
nit: v2 has now curly braces which v1 did not.

Either way, v2 is correct.


Tested-by: Alexey Kardashevskiy <redacted>
Reviewed-by: Alexey Kardashevskiy <redacted>





-- 
Alexey