Re: [PATCH] octeontx2-af: fix a use-after-free in rvu_npa_register_reporters

[Paolo Abeni <pabeni@redhat.com>]

On Sat, 2023-12-02 at 17:59 +0800, Zhipeng Lu wrote:
> The rvu_dl will be freed in rvu_npa_health_reporters_destroy(rvu_dl)
> after the create_workqueue fails, and after that free, the rvu_dl will
> be translate back through rvu_npa_health_reporters_create,
> rvu_health_reporters_create, and rvu_register_dl. Finally it goes to the
> err_dl_health label, being freed again in
> rvu_health_reporters_destroy(rvu) by rvu_npa_health_reporters_destroy.
> In the second calls of rvu_npa_health_reporters_destroy, however,
> it uses rvu_dl->rvu_npa_health_reporter, which is already freed at
> the end of rvu_npa_health_reporters_destroy in the first call.
> 
> So this patch prevents the first destroy by instantly returning -ENONMEN
> when create_workqueue fails. In addition, since the failure of
> create_workqueue is the only entrence of label err, it has been
> integrated into the error-handling path of create_workqueue.
> 
> Fixes: f1168d1e207c ("octeontx2-af: Add devlink health reporters for NPA")
> Signed-off-by: Zhipeng Lu <alexious@zju.edu.cn>
> ---
>  drivers/net/ethernet/marvell/octeontx2/af/rvu_devlink.c | 5 +----
>  1 file changed, 1 insertion(+), 4 deletions(-)
> 
> diff --git a/drivers/net/ethernet/marvell/octeontx2/af/rvu_devlink.c b/drivers/net/ethernet/marvell/octeontx2/af/rvu_devlink.c
> index 41df5ac23f92..058f75dc4c8a 100644
> --- a/drivers/net/ethernet/marvell/octeontx2/af/rvu_devlink.c
> +++ b/drivers/net/ethernet/marvell/octeontx2/af/rvu_devlink.c
> @@ -1285,7 +1285,7 @@ static int rvu_npa_register_reporters(struct rvu_devlink *rvu_dl)
>  
>  	rvu_dl->devlink_wq = create_workqueue("rvu_devlink_wq");
>  	if (!rvu_dl->devlink_wq)
> -		goto err;
> +		return -ENOMEM;
>  
>  	INIT_WORK(&rvu_reporters->intr_work, rvu_npa_intr_work);
>  	INIT_WORK(&rvu_reporters->err_work, rvu_npa_err_work);
> @@ -1293,9 +1293,6 @@ static int rvu_npa_register_reporters(struct rvu_devlink *rvu_dl)
>  	INIT_WORK(&rvu_reporters->ras_work, rvu_npa_ras_work);
>  
>  	return 0;
> -err:
> -	rvu_npa_health_reporters_destroy(rvu_dl);
> -	return -ENOMEM;
>  }
>  
>  static int rvu_npa_health_reporters_create(struct rvu_devlink *rvu_dl)

LGTM

Acked-by: Paolo Abeni <pabeni@redhat.com>

but allow some little more time for Marvel's people to have a better
look.

Cheers,

Paolo