[PATCH] net/mlx5e: fix bpf_prog refcnt leaks in mlx5e_alloc_rq

[PATCH] net/mlx5e: fix bpf_prog refcnt leaks in mlx5e_alloc_rq

[Xin Xiong]

The function invokes bpf_prog_inc(), which increases the refcount of a
bpf_prog object "rq->xdp_prog" if the object isn't NULL.

The refcount leak issues take place in two error handling paths. When
mlx5_wq_ll_create() or mlx5_wq_cyc_create() fails, the function simply
returns the error code and forgets to drop the refcount increased
earlier, causing a refcount leak of "rq->xdp_prog".

Fix this issue by jumping to the error handling path err_rq_wq_destroy
when either function fails.

Signed-off-by: Xin Xiong <xiongx18@fudan.edu.cn>
Signed-off-by: Xiyu Yang <xiyuyang19@fudan.edu.cn>
Signed-off-by: Xin Tan <tanxin.ctf@gmail.com>
---
 drivers/net/ethernet/mellanox/mlx5/core/en_main.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
index a836a02a2116..8e1b1ab416d8 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
@@ -419,7 +419,7 @@ static int mlx5e_alloc_rq(struct mlx5e_channel *c,
 		err = mlx5_wq_ll_create(mdev, &rqp->wq, rqc_wq, &rq->mpwqe.wq,
 					&rq->wq_ctrl);
 		if (err)
-			return err;
+			goto err_rq_wq_destroy;
 
 		rq->mpwqe.wq.db = &rq->mpwqe.wq.db[MLX5_RCV_DBR];
 
@@ -470,7 +470,7 @@ static int mlx5e_alloc_rq(struct mlx5e_channel *c,
 		err = mlx5_wq_cyc_create(mdev, &rqp->wq, rqc_wq, &rq->wqe.wq,
 					 &rq->wq_ctrl);
 		if (err)
-			return err;
+			goto err_rq_wq_destroy;
 
 		rq->wqe.wq.db = &rq->wqe.wq.db[MLX5_RCV_DBR];
 
-- 
2.25.1

Re: [PATCH] net/mlx5e: fix bpf_prog refcnt leaks in mlx5e_alloc_rq

[Saeed Mahameed]

On Wed, 2020-07-29 at 20:33 +0800, Xin Xiong wrote:
> The function invokes bpf_prog_inc(), which increases the refcount of
> a
> bpf_prog object "rq->xdp_prog" if the object isn't NULL.
> 
> The refcount leak issues take place in two error handling paths. When
> mlx5_wq_ll_create() or mlx5_wq_cyc_create() fails, the function
> simply
> returns the error code and forgets to drop the refcount increased
> earlier, causing a refcount leak of "rq->xdp_prog".
> 
> Fix this issue by jumping to the error handling path
> err_rq_wq_destroy
> when either function fails.
> 

Fixes: 422d4c401edd ("net/mlx5e: RX, Split WQ objects for different RQ
types")

> 
> Signed-off-by: Xin Xiong <xiongx18@fudan.edu.cn>
> Signed-off-by: Xiyu Yang <xiyuyang19@fudan.edu.cn>
> Signed-off-by: Xin Tan <tanxin.ctf@gmail.com>
> ---
>  drivers/net/ethernet/mellanox/mlx5/core/en_main.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
> b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
> index a836a02a2116..8e1b1ab416d8 100644
> --- a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
> +++ b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
> @@ -419,7 +419,7 @@ static int mlx5e_alloc_rq(struct mlx5e_channel
> *c,
>  		err = mlx5_wq_ll_create(mdev, &rqp->wq, rqc_wq, &rq-
> >mpwqe.wq,
>  					&rq->wq_ctrl);
>  		if (err)
> -			return err;
> +			goto err_rq_wq_destroy;
>  
>  		rq->mpwqe.wq.db = &rq->mpwqe.wq.db[MLX5_RCV_DBR];
>  
> @@ -470,7 +470,7 @@ static int mlx5e_alloc_rq(struct mlx5e_channel
> *c,
>  		err = mlx5_wq_cyc_create(mdev, &rqp->wq, rqc_wq, &rq-
> >wqe.wq,
>  					 &rq->wq_ctrl);
>  		if (err)
> -			return err;
> +			goto err_rq_wq_destroy;
>  
>  		rq->wqe.wq.db = &rq->wqe.wq.db[MLX5_RCV_DBR];
>  

Re: [PATCH] net/mlx5e: fix bpf_prog refcnt leaks in mlx5e_alloc_rq

[David Miller]

From: Saeed Mahameed <saeedm@mellanox.com>
Date: Wed, 29 Jul 2020 19:02:15 +0000

> On Wed, 2020-07-29 at 20:33 +0800, Xin Xiong wrote:
>> The function invokes bpf_prog_inc(), which increases the refcount of
>> a
>> bpf_prog object "rq->xdp_prog" if the object isn't NULL.
>> 
>> The refcount leak issues take place in two error handling paths. When
>> mlx5_wq_ll_create() or mlx5_wq_cyc_create() fails, the function
>> simply
>> returns the error code and forgets to drop the refcount increased
>> earlier, causing a refcount leak of "rq->xdp_prog".
>> 
>> Fix this issue by jumping to the error handling path
>> err_rq_wq_destroy
>> when either function fails.
>> 
> 
> Fixes: 422d4c401edd ("net/mlx5e: RX, Split WQ objects for different RQ
> types")

Saeed, are you going to take this into your tree or would you like me to
apply it directly?

Thanks.

Re: [PATCH] net/mlx5e: fix bpf_prog refcnt leaks in mlx5e_alloc_rq

[Saeed Mahameed]

On Wed, 2020-07-29 at 13:28 -0700, David Miller wrote:
> From: Saeed Mahameed <saeedm@mellanox.com>
> Date: Wed, 29 Jul 2020 19:02:15 +0000
> 
> >> Fix this issue by jumping to the error handling path
> >> err_rq_wq_destroy
> >> when either function fails.
> >> 
> > 
> > Fixes: 422d4c401edd ("net/mlx5e: RX, Split WQ objects for different
> RQ
> > types")
> 
> Saeed, are you going to take this into your tree or would you like me
> to
> apply it directly?
> 
> Thanks.

I will take this to my tree once Xin adds the missing Fixes tag.
Thanks.