Re: [PATCH 2/4] crypto: hisilicon/sec2 - fix scheduling while atomic in aead soft fallback

[Herbert Xu <herbert@gondor.apana.org.au>]

On Fri, Sep 11, 2026 at 06:29:40PM +0800, Chenghai Huang wrote:
> From: Wenkai Lin <linwenkai6@hisilicon.com>
> 
> sec_aead_soft_crypto() allocates the sub-request with GFP_KERNEL, which
> may sleep.  This is safe when called directly from sec_aead_crypto()
> (process context), but the function is also reachable through the
> backlog drain path.
> 
> When an AEAD request sits in the backlog queue and qp_send_message()
> returns a non-EBUSY error, the backlog is drained in software while
> the backlog spinlock is still held. The GFP_KERNEL allocation inside
> aead_request_alloc() can then schedule out, triggering scheduling
> while atomic.
> 
> Fix it by switching the allocation to GFP_ATOMIC so it is safe in both
> the process-context path and the spinlock-held backlog drain path.
> 
> Fixes: 0a2a464f8631 ("crypto: hisilicon/sec - fix the aead software fallback for engine")
> Signed-off-by: Wenkai Lin <linwenkai6@hisilicon.com>
> Signed-off-by: Chenghai Huang <huangchenghai2@huawei.com>
> ---
>  drivers/crypto/hisilicon/sec2/sec_crypto.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/crypto/hisilicon/sec2/sec_crypto.c b/drivers/crypto/hisilicon/sec2/sec_crypto.c
> index 0a2f7c8b44fc..bbb6826ab256 100644
> --- a/drivers/crypto/hisilicon/sec2/sec_crypto.c
> +++ b/drivers/crypto/hisilicon/sec2/sec_crypto.c
> @@ -2533,7 +2533,7 @@ static int sec_aead_soft_crypto(struct sec_ctx *ctx,
>  	struct aead_request *subreq;
>  	int ret;
>  
> -	subreq = aead_request_alloc(a_ctx->fallback_aead_tfm, GFP_KERNEL);
> +	subreq = aead_request_alloc(a_ctx->fallback_aead_tfm, GFP_ATOMIC);

Please use SYNC_AEAD_REQUEST_ON_STACK for the fallback.

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