diff --git a/crypto/dh.c b/crypto/dh.c
index 68d11d66c0b5..afc0fd847761 100644
--- a/crypto/dh.c
+++ b/crypto/dh.c
@@ -145,9 +145,9 @@ static int dh_is_pubkey_valid(struct dh_ctx *ctx, MPI y)
 	 * ->p is odd, so no need to explicitly subtract one
 	 * from it before shifting to the right.
 	 */
-	mpi_rshift(q, ctx->p, 1);
+	ret = mpi_rshift(q, ctx->p, 1) ?:
+	      mpi_powm(val, y, q, ctx->p);
 
-	ret = mpi_powm(val, y, q, ctx->p);
 	mpi_free(q);
 	if (ret) {
 		mpi_free(val);