Re: general protection fault in af_alg_free_areq_sgls

On Tue, Nov 28, 2017 at 10:10:55AM +0100, Stephan Mueller wrote:

quoted

diff --git a/crypto/af_alg.c b/crypto/af_alg.c
index 358749c38894..415a54ced4d6 100644
--- a/crypto/af_alg.c
+++ b/crypto/af_alg.c

@@ -672,14 +672,15 @@ void af_alg_free_areq_sgls(struct af_alg_async_req

*areq) }

 	tsgl = areq->tsgl;
-	for_each_sg(tsgl, sg, areq->tsgl_entries, i) {
-		if (!sg_page(sg))
-			continue;
-		put_page(sg_page(sg));
-	}
+	if (tsgl) {
+		for_each_sg(tsgl, sg, areq->tsgl_entries, i) {
+			if (!sg_page(sg))
+				continue;
+			put_page(sg_page(sg));
+		}

-	if (areq->tsgl && areq->tsgl_entries)

Why do you want to remove the check for areq->tsgl_entries? I know in the 
current code that cannot happen. But it should be caught in case of a 
programming error.

Thus, should we add a BUG_ON(!areq->tsgl_entries)?

sock_kfree_s() works even if the size is 0.  So there's no reason to check.

Eric