Re: [PATCH] crypto: api - Do not create test larvals if manager is disabled

[Geert Uytterhoeven <geert@linux-m68k.org>]

 	Hi Herbert,

On Tue, 19 Oct 2021, Herbert Xu wrote:
> On Tue, Oct 05, 2021 at 07:33:28PM -0700, Nathan Chancellor wrote:
>> I assume this is the diff you mean? This does not resolve the issue. My
>> apologies if I am slow to respond, I am on vacation until the middle of
>> next week.
>
> Sorry for the delay.  The kernel robot figured out the problem
> for me.  It's the crypto_alg_tested call that causes api.c to
> depend on algapi.c.  This call is only invoked in the case where
> the crypto manager is turned off.  We could instead simply make
> test larvals disappear in that case.
>
> ---8<---
> The delayed boot-time testing patch created a dependency loop
> between api.c and algapi.c because it added a crypto_alg_tested
> call to the former when the crypto manager is disabled.
>
> We could instead avoid creating the test larvals if the crypto
> manager is disabled.  This avoids the dependency loop as well
> as saving some unnecessary work, albeit in a very unlikely case.
>
> Reported-by: Nathan Chancellor <nathan@kernel.org>
> Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org>
> Reported-by: kernel test robot <lkp@intel.com>
> Fixes: adad556efcdd ("crypto: api - Fix built-in testing dependency failures")
> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

Thanks for your patch, which is now commit cad439fc040efe5f
("crypto: api - Do not create test larvals if manager is disabled").

I have bisected a failure to mount the root file system on k210 to this
commit.

Dmesg before/after:

      mmcblk0: mmc0:0000 SA04G 3.68 GiB
      random: fast init done
       mmcblk0: p1
     -EXT4-fs (mmcblk0p1): mounted filesystem with ordered data mode. Opts: (null). Quota mode: disabled.
     -VFS: Mounted root (ext4 filesystem) readonly on device 179:1.
     +EXT4-fs (mmcblk0p1): Cannot load crc32c driver.
     +VFS: Cannot open root device "mmcblk0p1" or unknown-block(179,1): error -80
     +Please append a correct "root=" boot option; here are the available partitions:
     +b300         3858432 mmcblk0
     + driver: mmcblk
     +  b301         3854336 mmcblk0p1 00000000-01

> --- a/crypto/algapi.c
> +++ b/crypto/algapi.c
> @@ -216,6 +216,32 @@ void crypto_remove_spawns(struct crypto_alg *alg, struct list_head *list,
> }
> EXPORT_SYMBOL_GPL(crypto_remove_spawns);
>
> +static struct crypto_larval *crypto_alloc_test_larval(struct crypto_alg *alg)
> +{
> +	struct crypto_larval *larval;
> +
> +	if (!IS_ENABLED(CONFIG_CRYPTO_MANAGER))
> +		return NULL;
> +
> +	larval = crypto_larval_alloc(alg->cra_name,
> +				     alg->cra_flags | CRYPTO_ALG_TESTED, 0);
> +	if (IS_ERR(larval))
> +		return larval;
> +
> +	larval->adult = crypto_mod_get(alg);
> +	if (!larval->adult) {
> +		kfree(larval);
> +		return ERR_PTR(-ENOENT);
> +	}
> +
> +	refcount_set(&larval->alg.cra_refcnt, 1);
> +	memcpy(larval->alg.cra_driver_name, alg->cra_driver_name,
> +	       CRYPTO_MAX_ALG_NAME);
> +	larval->alg.cra_priority = alg->cra_priority;
> +
> +	return larval;
> +}
> +
> static struct crypto_larval *__crypto_register_alg(struct crypto_alg *alg)
> {
> 	struct crypto_alg *q;
> @@ -250,31 +276,20 @@ static struct crypto_larval *__crypto_register_alg(struct crypto_alg *alg)
> 			goto err;
> 	}
>
> -	larval = crypto_larval_alloc(alg->cra_name,
> -				     alg->cra_flags | CRYPTO_ALG_TESTED, 0);
> +	larval = crypto_alloc_test_larval(alg);
> 	if (IS_ERR(larval))
> 		goto out;
>
> -	ret = -ENOENT;
> -	larval->adult = crypto_mod_get(alg);
> -	if (!larval->adult)
> -		goto free_larval;
> -
> -	refcount_set(&larval->alg.cra_refcnt, 1);
> -	memcpy(larval->alg.cra_driver_name, alg->cra_driver_name,
> -	       CRYPTO_MAX_ALG_NAME);
> -	larval->alg.cra_priority = alg->cra_priority;
> -
> 	list_add(&alg->cra_list, &crypto_alg_list);
> -	list_add(&larval->alg.cra_list, &crypto_alg_list);
> +
> +	if (larval)
> +		list_add(&larval->alg.cra_list, &crypto_alg_list);
>
> 	crypto_stats_init(alg);
>
> out:
> 	return larval;
>
> -free_larval:
> -	kfree(larval);
> err:
> 	larval = ERR_PTR(ret);
> 	goto out;
> @@ -403,10 +418,11 @@ int crypto_register_alg(struct crypto_alg *alg)
> 	down_write(&crypto_alg_sem);
> 	larval = __crypto_register_alg(alg);
> 	test_started = static_key_enabled(&crypto_boot_test_finished);
> -	larval->test_started = test_started;
> +	if (!IS_ERR_OR_NULL(larval))
> +		larval->test_started = test_started;
> 	up_write(&crypto_alg_sem);
>
> -	if (IS_ERR(larval))
> +	if (IS_ERR_OR_NULL(larval))
> 		return PTR_ERR(larval);
>
> 	if (test_started)
> @@ -616,8 +632,8 @@ int crypto_register_instance(struct crypto_template *tmpl,
> 	larval = __crypto_register_alg(&inst->alg);
> 	if (IS_ERR(larval))
> 		goto unlock;
> -
> -	larval->test_started = true;
> +	else if (larval)
> +		larval->test_started = true;
>
> 	hlist_add_head(&inst->list, &tmpl->instances);
> 	inst->tmpl = tmpl;
> @@ -626,7 +642,7 @@ int crypto_register_instance(struct crypto_template *tmpl,
> 	up_write(&crypto_alg_sem);
>
> 	err = PTR_ERR(larval);
> -	if (IS_ERR(larval))
> +	if (IS_ERR_OR_NULL(larval))
> 		goto err;
>
> 	crypto_wait_for_test(larval);
> diff --git a/crypto/api.c b/crypto/api.c
> index ee5991fe11f8..cf0869dd130b 100644
> --- a/crypto/api.c
> +++ b/crypto/api.c
> @@ -167,11 +167,8 @@ void crypto_wait_for_test(struct crypto_larval *larval)
> 	int err;
>
> 	err = crypto_probing_notify(CRYPTO_MSG_ALG_REGISTER, larval->adult);
> -	if (err != NOTIFY_STOP) {
> -		if (WARN_ON(err != NOTIFY_DONE))
> -			goto out;
> -		crypto_alg_tested(larval->alg.cra_driver_name, 0);
> -	}
> +	if (WARN_ON_ONCE(err != NOTIFY_STOP))
> +		goto out;
>
> 	err = wait_for_completion_killable(&larval->completion);
> 	WARN_ON(err);

Gr{oetje,eeting}s,

 						Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
 							    -- Linus Torvalds