On 01/08/2015 01:52 PM, Ilia Mirkin wrote:
On Thu, Jan 8, 2015 at 12:40 AM, Vince Hsu <vinceh@xxxxxxxxxx> wrote:
On 01/08/2015 12:57 PM, Ilia Mirkin wrote:
On Wed, Jan 7, 2015 at 11:32 PM, Vince Hsu <vinceh@xxxxxxxxxx> wrote:
On 01/08/2015 10:45 AM, Ilia Mirkin wrote:
On Wed, Jan 7, 2015 at 5:29 PM, Andy Shevchenko
<andy.shevchenko@xxxxxxxxx> wrote:
We have to check pointer before usage.
Reported-by: Andrey Karpov <karpov@xxxxxxxxxx>
Signed-off-by: Andy Shevchenko <andy.shevchenko@xxxxxxxxx>
---
drivers/gpu/drm/nouveau/core/subdev/clock/base.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/nouveau/core/subdev/clock/base.c
b/drivers/gpu/drm/nouveau/core/subdev/clock/base.c
index e51b72d..2e84436 100644
--- a/drivers/gpu/drm/nouveau/core/subdev/clock/base.c
+++ b/drivers/gpu/drm/nouveau/core/subdev/clock/base.c
@@ -322,7 +322,6 @@ nouveau_pstate_new(struct nouveau_clock *clk, int
idx)
return 0;
pstate = kzalloc(sizeof(*pstate), GFP_KERNEL);
- cstate = &pstate->base;
What's wrong with this line? If pstate == NULL, &pstate->base == NULL
as well and we return.
If pstate == NULL (kzalloc returned NULL), pstate->base triggers a null
pointer
deference error?
Where do you see "pstate->base"? I only see "&pstate->base" which
merely computes an offset into a structure... No reason to dereference
pstate.
Sorry that I don't quite understand. We do need deference pstate to get
the member base which has type nouveau_cstate, and then assign
the address of base to cstate for later use.
struct nouveau_pstate {
struct list_head head;
struct list_head list; /* c-states */
struct nouveau_cstate base;
u8 pstate;
u8 fanspeed;
};
&pstate->base is the same thing as
(void *)pstate + offsetof(struct nouveau_pstate, base)
At no point is pstate dereferenced. In fact, take a look at
http://en.wikipedia.org/wiki/Offsetof
which says that the traditional implementation of offsetof is
#define offsetof(st, m) ((size_t)(&((st *)0)->m))
Oh I got your point. You're absolutely right. Thanks for the patience. :)
Vince
-----------------------------------------------------------------------------------
This email message is for the sole use of the intended recipient(s) and may contain
confidential information. Any unauthorized review, use, disclosure or distribution
is prohibited. If you are not the intended recipient, please contact the sender by
reply email and destroy all copies of the original message.
-----------------------------------------------------------------------------------
_______________________________________________
dri-devel mailing list
dri-devel@xxxxxxxxxxxxxxxxxxxxx
http://lists.freedesktop.org/mailman/listinfo/dri-devel
