Date:   Tue, 21 Dec 2021 09:12:56 +0100
From:   Nicolas Toromanoff <nicolas.toromanoff@foss.st.com>
To:     Marek Vasut <marex@denx.de>
CC:     <linux-crypto@vger.kernel.org>,
        Lionel Debieve <lionel.debieve@st.com>,
        Nicolas Toromanoff <nicolas.toromanoff@st.com>,
        Herbert Xu <herbert@gondor.apana.org.au>,
        Alexandre Torgue <alexandre.torgue@foss.st.com>,
        <stable@vger.kernel.org>, Fabien Dessenne <fabien.dessenne@st.com>,
        <linux-stm32@st-md-mailman.stormreply.com>,
        <linux-arm-kernel@lists.infradead.org>
Subject: Re: [Linux-stm32] [PATCH] crypto: stm32/crc32 - Fix kernel BUG
 triggered in probe()
In-Reply-To: <20211220195022.1387104-1-marex@denx.de>
Message-ID: <alpine.DEB.2.21.2112210826250.21632@gnbcxd0088.gnb.st.com>
References: <20211220195022.1387104-1-marex@denx.de>
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On Mon, 20 Dec 2021, Marek Vasut wrote:

> The include/linux/crypto.h struct crypto_alg field cra_driver_name description
> states "Unique name of the transformation provider. " ... " this contains the
> name of the chip or provider and the name of the transformation algorithm."
>
> In case of the stm32-crc driver, field cra_driver_name is identical for all
> registered transformation providers and set to the name of the driver itself,
> which is incorrect. This patch fixes it by assigning a unique cra_driver_name
> to each registered transformation provider.
>
> The kernel crash is triggered when the driver calls crypto_register_shashes()
> which calls crypto_register_shash(), which calls crypto_register_alg(), which
> calls __crypto_register_alg(), which returns -EEXIST, which is propagated
> back through this call chain. Upon -EEXIST from crypto_register_shash(), the
> crypto_register_shashes() starts unregistering the providers back, and calls
> crypto_unregister_shash(), which calls crypto_unregister_alg(), and this is
> where the BUG() triggers due to incorrect cra_refcnt.
>
> Fixes: b51dbe90912a ("crypto: stm32 - Support for STM32 CRC32 crypto module")
> Signed-off-by: Marek Vasut <marex@denx.de>
> Cc: <stable@vger.kernel.org> # 4.12+
> Cc: Alexandre Torgue <alexandre.torgue@foss.st.com>
> Cc: Fabien Dessenne <fabien.dessenne@st.com>
> Cc: Herbert Xu <herbert@gondor.apana.org.au>
> Cc: Lionel Debieve <lionel.debieve@st.com>
> Cc: Nicolas Toromanoff <nicolas.toromanoff@st.com>
> Cc: linux-arm-kernel@lists.infradead.org
> Cc: linux-stm32@st-md-mailman.stormreply.com
> To: linux-crypto@vger.kernel.org
> ---
> drivers/crypto/stm32/stm32-crc32.c | 4 ++--

Hello Marek,

Thanks for the fix.

Acked-by: Nicolas Toromanoff <nicolas.toromanoff@foss.st.com>