| Message ID | 1420669790-6525-1-git-send-email-andy.shevchenko@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Wed, Jan 7, 2015 at 5:29 PM, Andy Shevchenko <andy.shevchenko@gmail.com> wrote: > We have to check pointer before usage. > > Reported-by: Andrey Karpov <karpov@viva64.com> > Signed-off-by: Andy Shevchenko <andy.shevchenko@gmail.com> > --- > 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) > return -ENOMEM; > > @@ -330,6 +329,9 @@ nouveau_pstate_new(struct nouveau_clock *clk, int idx) > > pstate->pstate = perfE.pstate; > pstate->fanspeed = perfE.fanspeed; > + > + cstate = &pstate->base; > + > cstate->voltage = perfE.voltage; > cstate->domain[nv_clk_src_core] = perfE.core; > cstate->domain[nv_clk_src_shader] = perfE.shader; > -- > 1.8.3.101.g727a46b > > _______________________________________________ > dri-devel mailing list > dri-devel@lists.freedesktop.org > http://lists.freedesktop.org/mailman/listinfo/dri-devel
On 01/08/2015 10:45 AM, Ilia Mirkin wrote: > On Wed, Jan 7, 2015 at 5:29 PM, Andy Shevchenko > <andy.shevchenko@gmail.com> wrote: >> We have to check pointer before usage. >> >> Reported-by: Andrey Karpov <karpov@viva64.com> >> Signed-off-by: Andy Shevchenko <andy.shevchenko@gmail.com> >> --- >> 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? Thanks, Vince > >> if (!pstate) >> return -ENOMEM; >> >> @@ -330,6 +329,9 @@ nouveau_pstate_new(struct nouveau_clock *clk, int idx) >> >> pstate->pstate = perfE.pstate; >> pstate->fanspeed = perfE.fanspeed; >> + >> + cstate = &pstate->base; >> + >> cstate->voltage = perfE.voltage; >> cstate->domain[nv_clk_src_core] = perfE.core; >> cstate->domain[nv_clk_src_shader] = perfE.shader; >> -- >> 1.8.3.101.g727a46b >> >> _______________________________________________ >> dri-devel mailing list >> dri-devel@lists.freedesktop.org >> http://lists.freedesktop.org/mailman/listinfo/dri-devel > _______________________________________________ > dri-devel mailing list > dri-devel@lists.freedesktop.org > http://lists.freedesktop.org/mailman/listinfo/dri-devel ----------------------------------------------------------------------------------- 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. -----------------------------------------------------------------------------------
On Wed, Jan 7, 2015 at 11:32 PM, Vince Hsu <vinceh@nvidia.com> wrote: > > On 01/08/2015 10:45 AM, Ilia Mirkin wrote: >> >> On Wed, Jan 7, 2015 at 5:29 PM, Andy Shevchenko >> <andy.shevchenko@gmail.com> wrote: >>> >>> We have to check pointer before usage. >>> >>> Reported-by: Andrey Karpov <karpov@viva64.com> >>> Signed-off-by: Andy Shevchenko <andy.shevchenko@gmail.com> >>> --- >>> 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. -ilia
On 01/08/2015 12:57 PM, Ilia Mirkin wrote: > On Wed, Jan 7, 2015 at 11:32 PM, Vince Hsu <vinceh@nvidia.com> wrote: >> On 01/08/2015 10:45 AM, Ilia Mirkin wrote: >>> On Wed, Jan 7, 2015 at 5:29 PM, Andy Shevchenko >>> <andy.shevchenko@gmail.com> wrote: >>>> We have to check pointer before usage. >>>> >>>> Reported-by: Andrey Karpov <karpov@viva64.com> >>>> Signed-off-by: Andy Shevchenko <andy.shevchenko@gmail.com> >>>> --- >>>> 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; }; Thanks, 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. -----------------------------------------------------------------------------------
On Thu, Jan 8, 2015 at 12:40 AM, Vince Hsu <vinceh@nvidia.com> wrote: > On 01/08/2015 12:57 PM, Ilia Mirkin wrote: >> >> On Wed, Jan 7, 2015 at 11:32 PM, Vince Hsu <vinceh@nvidia.com> wrote: >>> >>> On 01/08/2015 10:45 AM, Ilia Mirkin wrote: >>>> >>>> On Wed, Jan 7, 2015 at 5:29 PM, Andy Shevchenko >>>> <andy.shevchenko@gmail.com> wrote: >>>>> >>>>> We have to check pointer before usage. >>>>> >>>>> Reported-by: Andrey Karpov <karpov@viva64.com> >>>>> Signed-off-by: Andy Shevchenko <andy.shevchenko@gmail.com> >>>>> --- >>>>> 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)) Cheers, -ilia
On 01/08/2015 01:52 PM, Ilia Mirkin wrote: > On Thu, Jan 8, 2015 at 12:40 AM, Vince Hsu <vinceh@nvidia.com> wrote: >> On 01/08/2015 12:57 PM, Ilia Mirkin wrote: >>> On Wed, Jan 7, 2015 at 11:32 PM, Vince Hsu <vinceh@nvidia.com> wrote: >>>> On 01/08/2015 10:45 AM, Ilia Mirkin wrote: >>>>> On Wed, Jan 7, 2015 at 5:29 PM, Andy Shevchenko >>>>> <andy.shevchenko@gmail.com> wrote: >>>>>> We have to check pointer before usage. >>>>>> >>>>>> Reported-by: Andrey Karpov <karpov@viva64.com> >>>>>> Signed-off-by: Andy Shevchenko <andy.shevchenko@gmail.com> >>>>>> --- >>>>>> 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. -----------------------------------------------------------------------------------
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; if (!pstate) return -ENOMEM; @@ -330,6 +329,9 @@ nouveau_pstate_new(struct nouveau_clock *clk, int idx) pstate->pstate = perfE.pstate; pstate->fanspeed = perfE.fanspeed; + + cstate = &pstate->base; + cstate->voltage = perfE.voltage; cstate->domain[nv_clk_src_core] = perfE.core; cstate->domain[nv_clk_src_shader] = perfE.shader;
We have to check pointer before usage. Reported-by: Andrey Karpov <karpov@viva64.com> Signed-off-by: Andy Shevchenko <andy.shevchenko@gmail.com> --- drivers/gpu/drm/nouveau/core/subdev/clock/base.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)