Re: [PATCH v4 02/15] crypto: ti - Fix spinlock inconsistency in DTHEv2

[Herbert Xu]

On Thu, Sep 10, 2026 at 11:26:06PM +0530, T Pratham wrote:
> Probe and remove functions use spin_(un)lock for acquiring the
> dthe_dev_list.lock. But dthe_get_dev uses the bh variant. Change
> spin_(un)lock_bh to spin_(un)lock to avoid potential deadlock when a
> softIRQ process tries to acquire the already held lock.
> 
> Fixes: 52f641bc63a46 ("crypto: ti - Add driver for DTHE V2 AES Engine (ECB, CBC)")
> Signed-off-by: T Pratham <t-pratham@xxxxxx>
> ---
>  drivers/crypto/ti/dthev2-common.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/crypto/ti/dthev2-common.c b/drivers/crypto/ti/dthev2-common.c
> index cc02449382673..4c6b72ba104ec 100644
> --- a/drivers/crypto/ti/dthev2-common.c
> +++ b/drivers/crypto/ti/dthev2-common.c
> @@ -39,11 +39,11 @@ struct dthe_data *dthe_get_dev(struct dthe_tfm_ctx *ctx)
>  	if (ctx->dev_data)
>  		return ctx->dev_data;
>  
> -	spin_lock_bh(&dthe_dev_list.lock);
> +	spin_lock(&dthe_dev_list.lock);

This makes no sense.  The only time you can use a plain spin lock
is if all callers are from the same context, e.g., all with BH off
or all with BH on.

Because this function is called from the Crypto API, which allows
mixed BH context, you cannot safely use spin_lock.

In fact Sashiko reported this issue too:

https://sashiko.dev/#/patchset/20260910175619.2122149-1-t-pratham%40ti.com

Cheers,
-- 
Email: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt