[PATCH mlx5-next] net/mlx5: Check device memory pointer before usage

[PATCH mlx5-next] net/mlx5: Check device memory pointer before usage

[Leon Romanovsky]

From: Stav Aviram <saviram@nvidia.com>

Add a NULL check before accessing device memory to prevent a crash if
dev->dm allocation in mlx5_init_once() fails.

Fixes: c9b9dcb430b3 ("net/mlx5: Move device memory management to mlx5_core")
Signed-off-by: Stav Aviram <saviram@nvidia.com>
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
---
 drivers/infiniband/hw/mlx5/dm.c                  | 2 +-
 drivers/net/ethernet/mellanox/mlx5/core/lib/dm.c | 4 ++--
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/infiniband/hw/mlx5/dm.c b/drivers/infiniband/hw/mlx5/dm.c
index b4c97fb62abf..9ded2b7c1e31 100644
--- a/drivers/infiniband/hw/mlx5/dm.c
+++ b/drivers/infiniband/hw/mlx5/dm.c
@@ -282,7 +282,7 @@ static struct ib_dm *handle_alloc_dm_memic(struct ib_ucontext *ctx,
 	int err;
 	u64 address;
 
-	if (!MLX5_CAP_DEV_MEM(dm_db->dev, memic))
+	if (!dm_db || !MLX5_CAP_DEV_MEM(dm_db->dev, memic))
 		return ERR_PTR(-EOPNOTSUPP);
 
 	dm = kzalloc(sizeof(*dm), GFP_KERNEL);
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/lib/dm.c b/drivers/net/ethernet/mellanox/mlx5/core/lib/dm.c
index 7c5516b0a844..8115071c34a4 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/lib/dm.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/lib/dm.c
@@ -30,7 +30,7 @@ struct mlx5_dm *mlx5_dm_create(struct mlx5_core_dev *dev)
 
 	dm = kzalloc(sizeof(*dm), GFP_KERNEL);
 	if (!dm)
-		return ERR_PTR(-ENOMEM);
+		return NULL;
 
 	spin_lock_init(&dm->lock);
 
@@ -96,7 +96,7 @@ struct mlx5_dm *mlx5_dm_create(struct mlx5_core_dev *dev)
 err_steering:
 	kfree(dm);
 
-	return ERR_PTR(-ENOMEM);
+	return NULL;
 }
 
 void mlx5_dm_cleanup(struct mlx5_core_dev *dev)
-- 
2.50.0

Re: [PATCH mlx5-next] net/mlx5: Check device memory pointer before usage

[Michal Swiatkowski]

On Mon, Jun 30, 2025 at 01:35:53PM +0300, Leon Romanovsky wrote:
> From: Stav Aviram <saviram@nvidia.com>
> 
> Add a NULL check before accessing device memory to prevent a crash if
> dev->dm allocation in mlx5_init_once() fails.
> 
> Fixes: c9b9dcb430b3 ("net/mlx5: Move device memory management to mlx5_core")
> Signed-off-by: Stav Aviram <saviram@nvidia.com>
> Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
> ---
>  drivers/infiniband/hw/mlx5/dm.c                  | 2 +-
>  drivers/net/ethernet/mellanox/mlx5/core/lib/dm.c | 4 ++--
>  2 files changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/infiniband/hw/mlx5/dm.c b/drivers/infiniband/hw/mlx5/dm.c
> index b4c97fb62abf..9ded2b7c1e31 100644
> --- a/drivers/infiniband/hw/mlx5/dm.c
> +++ b/drivers/infiniband/hw/mlx5/dm.c
> @@ -282,7 +282,7 @@ static struct ib_dm *handle_alloc_dm_memic(struct ib_ucontext *ctx,
>  	int err;
>  	u64 address;
>  
> -	if (!MLX5_CAP_DEV_MEM(dm_db->dev, memic))
> +	if (!dm_db || !MLX5_CAP_DEV_MEM(dm_db->dev, memic))
>  		return ERR_PTR(-EOPNOTSUPP);
>  
>  	dm = kzalloc(sizeof(*dm), GFP_KERNEL);
> diff --git a/drivers/net/ethernet/mellanox/mlx5/core/lib/dm.c b/drivers/net/ethernet/mellanox/mlx5/core/lib/dm.c
> index 7c5516b0a844..8115071c34a4 100644
> --- a/drivers/net/ethernet/mellanox/mlx5/core/lib/dm.c
> +++ b/drivers/net/ethernet/mellanox/mlx5/core/lib/dm.c
> @@ -30,7 +30,7 @@ struct mlx5_dm *mlx5_dm_create(struct mlx5_core_dev *dev)
>  
>  	dm = kzalloc(sizeof(*dm), GFP_KERNEL);
>  	if (!dm)
> -		return ERR_PTR(-ENOMEM);
> +		return NULL;
>  
>  	spin_lock_init(&dm->lock);
>  
> @@ -96,7 +96,7 @@ struct mlx5_dm *mlx5_dm_create(struct mlx5_core_dev *dev)
>  err_steering:
>  	kfree(dm);
>  
> -	return ERR_PTR(-ENOMEM);
> +	return NULL;

In mlx5_init_once() IS_ERR is used (still). It should be consistent.
Looks like you can use IS_ERR() instead of checking just dm_db, however,
mlx5_dm_create() returns also NULL. I am not sure if it is fine (will
not cause an error in mlx5_init_once()).

Maybe the best is to change a check in mlx5_init_once() from IS_ERROR()
to just !dm.

Thanks

>  }
>  
>  void mlx5_dm_cleanup(struct mlx5_core_dev *dev)
> -- 
> 2.50.0

Re: [PATCH mlx5-next] net/mlx5: Check device memory pointer before usage

[Dawid Osuchowski]

On 2025-06-30 12:35 PM, Leon Romanovsky wrote:
> From: Stav Aviram <saviram@nvidia.com>
> 
> Add a NULL check before accessing device memory to prevent a crash if
> dev->dm allocation in mlx5_init_once() fails.
> 
> Fixes: c9b9dcb430b3 ("net/mlx5: Move device memory management to mlx5_core")
> Signed-off-by: Stav Aviram <saviram@nvidia.com>
> Signed-off-by: Leon Romanovsky <leonro@nvidia.com>

Given this is a fix, the net tree should be targeted instead of next.

Best regards,
Dawid

Re: [PATCH mlx5-next] net/mlx5: Check device memory pointer before usage

[Leon Romanovsky]

On Mon, Jun 30, 2025 at 01:18:22PM +0200, Dawid Osuchowski wrote:
> On 2025-06-30 12:35 PM, Leon Romanovsky wrote:
> > From: Stav Aviram <saviram@nvidia.com>
> > 
> > Add a NULL check before accessing device memory to prevent a crash if
> > dev->dm allocation in mlx5_init_once() fails.
> > 
> > Fixes: c9b9dcb430b3 ("net/mlx5: Move device memory management to mlx5_core")
> > Signed-off-by: Stav Aviram <saviram@nvidia.com>
> > Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
> 
> Given this is a fix, the net tree should be targeted instead of next.

This fix is mainly for RDMA and changes in net-next are by-product. The
current target is mlx5-next.

Thanks

> 
> Best regards,
> Dawid

Re: [PATCH mlx5-next] net/mlx5: Check device memory pointer before usage

[Leon Romanovsky]

On Mon, Jun 30, 2025 at 12:56:46PM +0200, Michal Swiatkowski wrote:
> On Mon, Jun 30, 2025 at 01:35:53PM +0300, Leon Romanovsky wrote:
> > From: Stav Aviram <saviram@nvidia.com>
> > 
> > Add a NULL check before accessing device memory to prevent a crash if
> > dev->dm allocation in mlx5_init_once() fails.
> > 
> > Fixes: c9b9dcb430b3 ("net/mlx5: Move device memory management to mlx5_core")
> > Signed-off-by: Stav Aviram <saviram@nvidia.com>
> > Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
> > ---
> >  drivers/infiniband/hw/mlx5/dm.c                  | 2 +-
> >  drivers/net/ethernet/mellanox/mlx5/core/lib/dm.c | 4 ++--
> >  2 files changed, 3 insertions(+), 3 deletions(-)
> > 
> > diff --git a/drivers/infiniband/hw/mlx5/dm.c b/drivers/infiniband/hw/mlx5/dm.c
> > index b4c97fb62abf..9ded2b7c1e31 100644
> > --- a/drivers/infiniband/hw/mlx5/dm.c
> > +++ b/drivers/infiniband/hw/mlx5/dm.c
> > @@ -282,7 +282,7 @@ static struct ib_dm *handle_alloc_dm_memic(struct ib_ucontext *ctx,
> >  	int err;
> >  	u64 address;
> >  
> > -	if (!MLX5_CAP_DEV_MEM(dm_db->dev, memic))
> > +	if (!dm_db || !MLX5_CAP_DEV_MEM(dm_db->dev, memic))
> >  		return ERR_PTR(-EOPNOTSUPP);
> >  
> >  	dm = kzalloc(sizeof(*dm), GFP_KERNEL);
> > diff --git a/drivers/net/ethernet/mellanox/mlx5/core/lib/dm.c b/drivers/net/ethernet/mellanox/mlx5/core/lib/dm.c
> > index 7c5516b0a844..8115071c34a4 100644
> > --- a/drivers/net/ethernet/mellanox/mlx5/core/lib/dm.c
> > +++ b/drivers/net/ethernet/mellanox/mlx5/core/lib/dm.c
> > @@ -30,7 +30,7 @@ struct mlx5_dm *mlx5_dm_create(struct mlx5_core_dev *dev)
> >  
> >  	dm = kzalloc(sizeof(*dm), GFP_KERNEL);
> >  	if (!dm)
> > -		return ERR_PTR(-ENOMEM);
> > +		return NULL;
> >  
> >  	spin_lock_init(&dm->lock);
> >  
> > @@ -96,7 +96,7 @@ struct mlx5_dm *mlx5_dm_create(struct mlx5_core_dev *dev)
> >  err_steering:
> >  	kfree(dm);
> >  
> > -	return ERR_PTR(-ENOMEM);
> > +	return NULL;
> 
> In mlx5_init_once() IS_ERR is used (still). It should be consistent.
> Looks like you can use IS_ERR() instead of checking just dm_db, however,
> mlx5_dm_create() returns also NULL. I am not sure if it is fine (will
> not cause an error in mlx5_init_once()).
> 
> Maybe the best is to change a check in mlx5_init_once() from IS_ERROR()
> to just !dm.

We need to remove IS_ERR() check from all places.

> 
> Thanks
> 
> >  }
> >  
> >  void mlx5_dm_cleanup(struct mlx5_core_dev *dev)
> > -- 
> > 2.50.0