Re: [PATCH][next] soc: fsl: dpio: fix dereference of pointer p before null check

[Dan Carpenter]

On Fri, Feb 21, 2020 at 11:11:43PM +, Colin King wrote:
> ---
>  drivers/soc/fsl/dpio/qbman-portal.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/soc/fsl/dpio/qbman-portal.c 
> b/drivers/soc/fsl/dpio/qbman-portal.c
> index 740ee0d19582..d1f49caa5b13 100644
> --- a/drivers/soc/fsl/dpio/qbman-portal.c
> +++ b/drivers/soc/fsl/dpio/qbman-portal.c
> @@ -249,10 +249,11 @@ struct qbman_swp *qbman_swp_init(const struct 
> qbman_swp_desc *d)
>   u32 mask_size;
>   u32 eqcr_pi;
>  
> - spin_lock_init(>access_spinlock);
> -
>   if (!p)
>   return NULL;
> +
> + spin_lock_init(>access_spinlock);

Allocations in the declaration blog are not super common in the kernel,
but they're more bug prone.  Generally, it's not beautiful to call a
function which can fail in the allocation block.

regards,
dan carpenter

RE: [PATCH][next] soc: fsl: dpio: fix dereference of pointer p before null check

[Leo Li]

> -Original Message-
> From: Colin King 
> Sent: Friday, February 21, 2020 5:12 PM
> To: Roy Pledge ; Leo Li ; Youri
> Querry ; linuxppc-dev@lists.ozlabs.org; linux-
> arm-ker...@lists.infradead.org
> Cc: kernel-janit...@vger.kernel.org; linux-ker...@vger.kernel.org
> Subject: [PATCH][next] soc: fsl: dpio: fix dereference of pointer p before 
> null
> check
> 
> From: Colin Ian King 
> 
> Pointer p is currently being dereferenced before it is null checked on a
> memory allocation failure check. Fix this by checking if p is null before
> dereferencing it.
> 
> Addresses-Coverity: ("Dereference before null check")
> Fixes: 3b2abda7d28c ("soc: fsl: dpio: Replace QMAN array mode with ring
> mode enqueue")
> Signed-off-by: Colin Ian King 

Applied for next.  Thanks.

> ---
>  drivers/soc/fsl/dpio/qbman-portal.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/soc/fsl/dpio/qbman-portal.c
> b/drivers/soc/fsl/dpio/qbman-portal.c
> index 740ee0d19582..d1f49caa5b13 100644
> --- a/drivers/soc/fsl/dpio/qbman-portal.c
> +++ b/drivers/soc/fsl/dpio/qbman-portal.c
> @@ -249,10 +249,11 @@ struct qbman_swp *qbman_swp_init(const struct
> qbman_swp_desc *d)
>   u32 mask_size;
>   u32 eqcr_pi;
> 
> - spin_lock_init(>access_spinlock);
> -
>   if (!p)
>   return NULL;
> +
> + spin_lock_init(>access_spinlock);
> +
>   p->desc = d;
>   p->mc.valid_bit = QB_VALID_BIT;
>   p->sdq = 0;
> --
> 2.25.0