Re: [PATCH] crypto: AF_ALG - remove locking in async callback

[Romain Izard <romain.izard.pro@gmail.com>]

2017-10-29 21:39 GMT+01:00 Stephan Müller <smueller@chronox.de>:
> Am Mittwoch, 25. Oktober 2017, 17:26:31 CET schrieb Romain Izard:
>
> Hi Romain,
>
> the patch below should cover the issue you see. Would you mind testing it?
>
> Thanks
> Stephan
>
> ---8<---
>
> The code paths protected by the socket-lock do not use or modify the
> socket in a non-atomic fashion. The actions pertaining the socket do not
> even need to be handled as an atomic operation. Thus, the socket-lock
> can be safely ignored.
>
> This fixes a bug regarding scheduling in atomic as the callback function
> may be invoked in interrupt context.
>
> Fixes: 2d97591ef43d0 ("crypto: af_alg - consolidation of duplicate code")
> Reported-by: Romain Izard <romain.izard.pro@gmail.com>
> Signed-off-by: Stephan Mueller <smueller@chronox.de>

Tested-by: Romain Izard <romain.izard.pro@gmail.com>

The issue observed with atmel-aes is not reproduced anymore.

> ---
>  crypto/af_alg.c | 4 ----
>  1 file changed, 4 deletions(-)
>
> diff --git a/crypto/af_alg.c b/crypto/af_alg.c
> index 337cf382718e..a41f08642eee 100644
> --- a/crypto/af_alg.c
> +++ b/crypto/af_alg.c
> @@ -1063,8 +1063,6 @@ void af_alg_async_cb(struct crypto_async_request *_req, int err)
>         struct kiocb *iocb = areq->iocb;
>         unsigned int resultlen;
>
> -       lock_sock(sk);
> -
>         /* Buffer size written by crypto operation. */
>         resultlen = areq->outlen;
>
> @@ -1073,8 +1071,6 @@ void af_alg_async_cb(struct crypto_async_request *_req, int err)
>         __sock_put(sk);
>
>         iocb->ki_complete(iocb, err ? err : resultlen, 0);
> -
> -       release_sock(sk);
>  }
>  EXPORT_SYMBOL_GPL(af_alg_async_cb);
>
> --
> 2.13.6
>
>