* [PATCH] drm/i915/gvt/scheduler: fix potential NULL pointer dereference
@ 2018-03-19 19:30 Gustavo A. R. Silva
2018-03-19 20:38 ` Chris Wilson
0 siblings, 1 reply; 6+ messages in thread
From: Gustavo A. R. Silva @ 2018-03-19 19:30 UTC (permalink / raw)
To: Zhenyu Wang, Zhi Wang, Jani Nikula, Joonas Lahtinen, Rodrigo Vivi,
David Airlie
Cc: intel-gvt-dev, intel-gfx, dri-devel, linux-kernel,
Gustavo A. R. Silva
_workload_ is being dereferenced before it is null checked, hence
there is a potential null pointer dereference.
Fix this by moving the pointer dereference after _workload_ has
been null checked.
Addresses-Coverity-ID: 1430136 ("Dereference before null check")
Fixes: fa3dd623e559 ("drm/i915/gvt: keep oa config in shadow ctx")
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
---
drivers/gpu/drm/i915/gvt/scheduler.c | 10 +++++++---
1 file changed, 7 insertions(+), 3 deletions(-)
diff --git a/drivers/gpu/drm/i915/gvt/scheduler.c b/drivers/gpu/drm/i915/gvt/scheduler.c
index 0681264..be1a297 100644
--- a/drivers/gpu/drm/i915/gvt/scheduler.c
+++ b/drivers/gpu/drm/i915/gvt/scheduler.c
@@ -60,9 +60,9 @@ static void set_context_pdp_root_pointer(
static void sr_oa_regs(struct intel_vgpu_workload *workload,
u32 *reg_state, bool save)
{
- struct drm_i915_private *dev_priv = workload->vgpu->gvt->dev_priv;
- u32 ctx_oactxctrl = dev_priv->perf.oa.ctx_oactxctrl_offset;
- u32 ctx_flexeu0 = dev_priv->perf.oa.ctx_flexeu0_offset;
+ struct drm_i915_private *dev_priv;
+ u32 ctx_oactxctrl;
+ u32 ctx_flexeu0;
int i = 0;
u32 flex_mmio[] = {
i915_mmio_reg_offset(EU_PERF_CNTL0),
@@ -77,6 +77,10 @@ static void sr_oa_regs(struct intel_vgpu_workload *workload,
if (!workload || !reg_state || workload->ring_id != RCS)
return;
+ dev_priv = workload->vgpu->gvt->dev_priv;
+ ctx_oactxctrl = dev_priv->perf.oa.ctx_oactxctrl_offset;
+ ctx_flexeu0 = dev_priv->perf.oa.ctx_flexeu0_offset;
+
if (save) {
workload->oactxctrl = reg_state[ctx_oactxctrl + 1];
--
2.7.4
^ permalink raw reply related [flat|nested] 6+ messages in thread* Re: [PATCH] drm/i915/gvt/scheduler: fix potential NULL pointer dereference
2018-03-19 19:30 [PATCH] drm/i915/gvt/scheduler: fix potential NULL pointer dereference Gustavo A. R. Silva
@ 2018-03-19 20:38 ` Chris Wilson
0 siblings, 0 replies; 6+ messages in thread
From: Chris Wilson @ 2018-03-19 20:38 UTC (permalink / raw)
To: Zhenyu Wang, Zhi Wang, Jani Nikula, Joonas Lahtinen, Rodrigo Vivi,
David Airlie
Cc: intel-gfx, intel-gvt-dev, linux-kernel, dri-devel,
Gustavo A. R. Silva
Quoting Gustavo A. R. Silva (2018-03-19 19:30:53)
> _workload_ is being dereferenced before it is null checked, hence
> there is a potential null pointer dereference.
>
> Fix this by moving the pointer dereference after _workload_ has
> been null checked.
The checks are misleading and not required.
-Chris
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] drm/i915/gvt/scheduler: fix potential NULL pointer dereference
@ 2018-03-19 20:38 ` Chris Wilson
0 siblings, 0 replies; 6+ messages in thread
From: Chris Wilson @ 2018-03-19 20:38 UTC (permalink / raw)
To: Gustavo A. R. Silva, Zhenyu Wang, Zhi Wang, Jani Nikula,
Joonas Lahtinen, Rodrigo Vivi, David Airlie
Cc: intel-gvt-dev, intel-gfx, dri-devel, linux-kernel,
Gustavo A. R. Silva
Quoting Gustavo A. R. Silva (2018-03-19 19:30:53)
> _workload_ is being dereferenced before it is null checked, hence
> there is a potential null pointer dereference.
>
> Fix this by moving the pointer dereference after _workload_ has
> been null checked.
The checks are misleading and not required.
-Chris
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] drm/i915/gvt/scheduler: fix potential NULL pointer dereference
2018-03-19 20:38 ` Chris Wilson
(?)
@ 2018-03-19 20:50 ` Gustavo A. R. Silva
2018-03-19 21:23 ` Chris Wilson
-1 siblings, 1 reply; 6+ messages in thread
From: Gustavo A. R. Silva @ 2018-03-19 20:50 UTC (permalink / raw)
To: Chris Wilson, Zhenyu Wang, Zhi Wang, Jani Nikula, Joonas Lahtinen,
Rodrigo Vivi, David Airlie
Cc: intel-gvt-dev, intel-gfx, dri-devel, linux-kernel
Hi Chris,
On 03/19/2018 03:38 PM, Chris Wilson wrote:
> Quoting Gustavo A. R. Silva (2018-03-19 19:30:53)
>> _workload_ is being dereferenced before it is null checked, hence
>> there is a potential null pointer dereference.
>>
>> Fix this by moving the pointer dereference after _workload_ has
>> been null checked.
>
> The checks are misleading and not required.
All of them?
if (!workload || !reg_state || workload->ring_id != RCS)
return;
or just the null check on workload ?
Thanks for the feedback.
--
Gustavo
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] drm/i915/gvt/scheduler: fix potential NULL pointer dereference
2018-03-19 20:50 ` Gustavo A. R. Silva
@ 2018-03-19 21:23 ` Chris Wilson
2018-03-19 21:45 ` Gustavo A. R. Silva
0 siblings, 1 reply; 6+ messages in thread
From: Chris Wilson @ 2018-03-19 21:23 UTC (permalink / raw)
To: Gustavo A. R. Silva, Zhenyu Wang, Zhi Wang, Jani Nikula,
Joonas Lahtinen, Rodrigo Vivi, David Airlie
Cc: intel-gvt-dev, intel-gfx, dri-devel, linux-kernel
Quoting Gustavo A. R. Silva (2018-03-19 20:50:12)
> Hi Chris,
>
> On 03/19/2018 03:38 PM, Chris Wilson wrote:
> > Quoting Gustavo A. R. Silva (2018-03-19 19:30:53)
> >> _workload_ is being dereferenced before it is null checked, hence
> >> there is a potential null pointer dereference.
> >>
> >> Fix this by moving the pointer dereference after _workload_ has
> >> been null checked.
> >
> > The checks are misleading and not required.
>
> All of them?
>
> if (!workload || !reg_state || workload->ring_id != RCS)
> return;
workload can not be NULL (dereference in caller), reg_state can not be
NULL (by construct from kmap()).
It may be not an RCS ring through.
-Chris
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] drm/i915/gvt/scheduler: fix potential NULL pointer dereference
2018-03-19 21:23 ` Chris Wilson
@ 2018-03-19 21:45 ` Gustavo A. R. Silva
0 siblings, 0 replies; 6+ messages in thread
From: Gustavo A. R. Silva @ 2018-03-19 21:45 UTC (permalink / raw)
To: Chris Wilson, Zhenyu Wang, Zhi Wang, Jani Nikula, Joonas Lahtinen,
Rodrigo Vivi, David Airlie
Cc: intel-gvt-dev, intel-gfx, dri-devel, linux-kernel
On 03/19/2018 04:23 PM, Chris Wilson wrote:
> Quoting Gustavo A. R. Silva (2018-03-19 20:50:12)
>> Hi Chris,
>>
>> On 03/19/2018 03:38 PM, Chris Wilson wrote:
>>> Quoting Gustavo A. R. Silva (2018-03-19 19:30:53)
>>>> _workload_ is being dereferenced before it is null checked, hence
>>>> there is a potential null pointer dereference.
>>>>
>>>> Fix this by moving the pointer dereference after _workload_ has
>>>> been null checked.
>>>
>>> The checks are misleading and not required.
>>
>> All of them?
>>
>> if (!workload || !reg_state || workload->ring_id != RCS)
>> return;
>
> workload can not be NULL (dereference in caller), reg_state can not be
> NULL (by construct from kmap()).
>
> It may be not an RCS ring through
I got it.
I'll send the following patch then:
--- a/drivers/gpu/drm/i915/gvt/scheduler.c
+++ b/drivers/gpu/drm/i915/gvt/scheduler.c
@@ -74,7 +74,7 @@ static void sr_oa_regs(struct intel_vgpu_workload
*workload,
i915_mmio_reg_offset(EU_PERF_CNTL6),
};
- if (!workload || !reg_state || workload->ring_id != RCS)
+ if(workload->ring_id != RCS)
return;
if (save) {
Thanks
--
Gustavo
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2018-03-19 21:45 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz follow: Atom feed
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2018-03-19 19:30 [PATCH] drm/i915/gvt/scheduler: fix potential NULL pointer dereference Gustavo A. R. Silva
2018-03-19 20:38 ` Chris Wilson
2018-03-19 20:38 ` Chris Wilson
2018-03-19 20:50 ` Gustavo A. R. Silva
2018-03-19 21:23 ` Chris Wilson
2018-03-19 21:45 ` Gustavo A. R. Silva
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