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* [PATCH] vme: Added NULL check for bridge
@ 2022-06-19  7:06 Souptick Joarder
  2022-06-20  8:02 ` Greg KH
  2022-06-20  8:49 ` Dan Carpenter
  0 siblings, 2 replies; 3+ messages in thread
From: Souptick Joarder @ 2022-06-19  7:06 UTC (permalink / raw)
  To: martyn, manohar.vanga, gregkh, alexandre.belloni, rafael,
	mathieu.poirier, u.kleine-koenig, arnd
  Cc: linux-kernel, linux-staging, Souptick Joarder (HPE),
	Kernel test robot

From: "Souptick Joarder (HPE)" <jrdr.linux@gmail.com>

Kernel test robot throws below warning ->
drivers/staging/vme_user/vme.c:662:20: warning: dereference
of NULL 'bridge' [CWE-476] [-Wanalyzer-null-dereference]

Added a NULL check.

Reported-by: Kernel test robot <lkp@intel.com>
Signed-off-by: Souptick Joarder (HPE) <jrdr.linux@gmail.com>
---
 drivers/staging/vme_user/vme.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/staging/vme_user/vme.c b/drivers/staging/vme_user/vme.c
index b5555683a069..ede774f2fe5a 100644
--- a/drivers/staging/vme_user/vme.c
+++ b/drivers/staging/vme_user/vme.c
@@ -659,7 +659,7 @@ ssize_t vme_master_read(struct vme_resource *resource, void *buf, size_t count,
 	struct vme_master_resource *image;
 	size_t length;
 
-	if (!bridge->master_read) {
+	if (bridge && !bridge->master_read) {
 		printk(KERN_WARNING "Reading from resource not supported\n");
 		return -EINVAL;
 	}
-- 
2.25.1


^ permalink raw reply related	[flat|nested] 3+ messages in thread

* Re: [PATCH] vme: Added NULL check for bridge
  2022-06-19  7:06 [PATCH] vme: Added NULL check for bridge Souptick Joarder
@ 2022-06-20  8:02 ` Greg KH
  2022-06-20  8:49 ` Dan Carpenter
  1 sibling, 0 replies; 3+ messages in thread
From: Greg KH @ 2022-06-20  8:02 UTC (permalink / raw)
  To: Souptick Joarder
  Cc: martyn, manohar.vanga, alexandre.belloni, rafael, mathieu.poirier,
	u.kleine-koenig, arnd, linux-kernel, linux-staging,
	Kernel test robot

On Sun, Jun 19, 2022 at 12:36:45PM +0530, Souptick Joarder wrote:
> From: "Souptick Joarder (HPE)" <jrdr.linux@gmail.com>
> 
> Kernel test robot throws below warning ->
> drivers/staging/vme_user/vme.c:662:20: warning: dereference
> of NULL 'bridge' [CWE-476] [-Wanalyzer-null-dereference]
> 
> Added a NULL check.
> 
> Reported-by: Kernel test robot <lkp@intel.com>
> Signed-off-by: Souptick Joarder (HPE) <jrdr.linux@gmail.com>
> ---
>  drivers/staging/vme_user/vme.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/staging/vme_user/vme.c b/drivers/staging/vme_user/vme.c
> index b5555683a069..ede774f2fe5a 100644
> --- a/drivers/staging/vme_user/vme.c
> +++ b/drivers/staging/vme_user/vme.c
> @@ -659,7 +659,7 @@ ssize_t vme_master_read(struct vme_resource *resource, void *buf, size_t count,
>  	struct vme_master_resource *image;
>  	size_t length;
>  
> -	if (!bridge->master_read) {
> +	if (bridge && !bridge->master_read) {

How can bridge ever be NULL here?

thanks,

greg k-h

^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: [PATCH] vme: Added NULL check for bridge
  2022-06-19  7:06 [PATCH] vme: Added NULL check for bridge Souptick Joarder
  2022-06-20  8:02 ` Greg KH
@ 2022-06-20  8:49 ` Dan Carpenter
  1 sibling, 0 replies; 3+ messages in thread
From: Dan Carpenter @ 2022-06-20  8:49 UTC (permalink / raw)
  To: Souptick Joarder
  Cc: martyn, manohar.vanga, gregkh, alexandre.belloni, rafael,
	mathieu.poirier, u.kleine-koenig, arnd, linux-kernel,
	linux-staging, Kernel test robot

On Sun, Jun 19, 2022 at 12:36:45PM +0530, Souptick Joarder wrote:
> From: "Souptick Joarder (HPE)" <jrdr.linux@gmail.com>
> 
> Kernel test robot throws below warning ->
> drivers/staging/vme_user/vme.c:662:20: warning: dereference
> of NULL 'bridge' [CWE-476] [-Wanalyzer-null-dereference]
> 
> Added a NULL check.
> 
> Reported-by: Kernel test robot <lkp@intel.com>
> Signed-off-by: Souptick Joarder (HPE) <jrdr.linux@gmail.com>
> ---
>  drivers/staging/vme_user/vme.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/staging/vme_user/vme.c b/drivers/staging/vme_user/vme.c
> index b5555683a069..ede774f2fe5a 100644
> --- a/drivers/staging/vme_user/vme.c
> +++ b/drivers/staging/vme_user/vme.c
> @@ -659,7 +659,7 @@ ssize_t vme_master_read(struct vme_resource *resource, void *buf, size_t count,
>  	struct vme_master_resource *image;
>  	size_t length;
>  
> -	if (!bridge->master_read) {
> +	if (bridge && !bridge->master_read) {

This patch does not help anything.  If "bridge" is NULL here then the
kernel will just crash later in the function.  Smatch complains about it
now:

drivers/staging/vme_user/vme.c:688 vme_master_read() error: we previously assumed 'bridge' could be null (see line 666)

However, I don't believe that bridge can actually be NULL here.  We do
not write code just to silence that static checker false positives.  Fix
the checker instead.

regards,
dan carpenter


^ permalink raw reply	[flat|nested] 3+ messages in thread

end of thread, other threads:[~2022-06-20  8:50 UTC | newest]

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2022-06-19  7:06 [PATCH] vme: Added NULL check for bridge Souptick Joarder
2022-06-20  8:02 ` Greg KH
2022-06-20  8:49 ` Dan Carpenter

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