On Thu, Apr 09, 2015 at 11:22:19AM +0200, Stephan Mueller wrote:
>
> I tested it and this approach does not work.
>
> If I see that right, the reason for that is the following: The suggestion is
> to grab the ref count at the start of the function followed by a
> __crypto_register_alg. __crypto_register_alg however sets the refcount to 1
> unconditionally. That means that the final put of the alg will most likely set
> the refcount to 0 that causes an issue with all other operations (at least I
> cannot allocate HMAC or CMAC any more -- the ones I currently test).
>
> So, the grabing of the alg must happen after the invocation of
> __crypto_register_alg.
Well let's move it then.
---8<---
crypto: api - Move alg ref count init to crypto_check_alg
We currently initialise the crypto_alg ref count in the function
__crypto_register_alg. As one of the callers of that function
crypto_register_instance needs to obtain a ref count before it
calls __crypto_register_alg, we need to move the initialisation
out of there.
Since both callers of __crypto_register_alg call crypto_check_alg,
this is the logical place to perform the initialisation.
Signed-off-by: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
diff --git a/crypto/algapi.c b/crypto/algapi.c
index f1d0307..1462c68 100644
--- a/crypto/algapi.c
+++ b/crypto/algapi.c
@@ -64,6 +64,8 @@ static int crypto_check_alg(struct crypto_alg *alg)
if (alg->cra_priority < 0)
return -EINVAL;
+ atomic_set(&alg->cra_refcnt, 1);
+
return crypto_set_driver_name(alg);
}
@@ -187,7 +189,6 @@ static struct crypto_larval *__crypto_register_alg(struct crypto_alg *alg)
ret = -EEXIST;
- atomic_set(&alg->cra_refcnt, 1);
list_for_each_entry(q, &crypto_alg_list, cra_list) {
if (q == alg)
goto err;
--
Email: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
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