* [PATCH] drm/v3d: Fix null pointer dereference of pointer perfmon
@ 2022-04-24 18:35 Colin Ian King
2022-04-25 7:10 ` Juan A. Suárez
0 siblings, 1 reply; 4+ messages in thread
From: Colin Ian King @ 2022-04-24 18:35 UTC (permalink / raw)
To: Emma Anholt, David Airlie, Daniel Vetter, Melissa Wen,
Juan A . Suarez Romero, dri-devel
Cc: kernel-janitors, linux-kernel
In the unlikely event that pointer perfmon is null the WARN_ON return path
occurs after the pointer has already been deferenced. Fix this by only
dereferencing perfmon after it has been null checked.
Fixes: 26a4dc29b74a ("drm/v3d: Expose performance counters to userspace")
Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
---
drivers/gpu/drm/v3d/v3d_perfmon.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/v3d/v3d_perfmon.c b/drivers/gpu/drm/v3d/v3d_perfmon.c
index 0288ef063513..f6a88abccc7d 100644
--- a/drivers/gpu/drm/v3d/v3d_perfmon.c
+++ b/drivers/gpu/drm/v3d/v3d_perfmon.c
@@ -25,11 +25,12 @@ void v3d_perfmon_start(struct v3d_dev *v3d, struct v3d_perfmon *perfmon)
{
unsigned int i;
u32 mask;
- u8 ncounters = perfmon->ncounters;
+ u8 ncounters;
if (WARN_ON_ONCE(!perfmon || v3d->active_perfmon))
return;
+ ncounters = perfmon->ncounters;
mask = GENMASK(ncounters - 1, 0);
for (i = 0; i < ncounters; i++) {
--
2.35.1
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH] drm/v3d: Fix null pointer dereference of pointer perfmon
2022-04-24 18:35 [PATCH] drm/v3d: Fix null pointer dereference of pointer perfmon Colin Ian King
@ 2022-04-25 7:10 ` Juan A. Suárez
2022-04-26 12:58 ` Melissa Wen
0 siblings, 1 reply; 4+ messages in thread
From: Juan A. Suárez @ 2022-04-25 7:10 UTC (permalink / raw)
To: Colin Ian King, Emma Anholt, David Airlie, Daniel Vetter,
Melissa Wen, dri-devel
Cc: kernel-janitors, linux-kernel
On Sun, 2022-04-24 at 19:35 +0100, Colin Ian King wrote:
> In the unlikely event that pointer perfmon is null the WARN_ON return
> path
> occurs after the pointer has already been deferenced. Fix this by
> only
> dereferencing perfmon after it has been null checked.
>
Good catch!
Reviewed-by: Juan A. Suarez <jasuarez@igalia.com>
J.A.
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] drm/v3d: Fix null pointer dereference of pointer perfmon
2022-04-25 7:10 ` Juan A. Suárez
@ 2022-04-26 12:58 ` Melissa Wen
0 siblings, 0 replies; 4+ messages in thread
From: Melissa Wen @ 2022-04-26 12:58 UTC (permalink / raw)
To: Juan A. Suárez
Cc: Colin Ian King, Emma Anholt, David Airlie, Daniel Vetter,
dri-devel, kernel-janitors, linux-kernel
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On 04/25, Juan A. Suárez wrote:
> On Sun, 2022-04-24 at 19:35 +0100, Colin Ian King wrote:
> > In the unlikely event that pointer perfmon is null the WARN_ON return
> > path
> > occurs after the pointer has already been deferenced. Fix this by
> > only
> > dereferencing perfmon after it has been null checked.
> >
>
> Good catch!
>
> Reviewed-by: Juan A. Suarez <jasuarez@igalia.com>
Applied to drm-misc-next.
Thanks,
Melissa
>
>
> J.A.
>
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^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] drm/v3d: Fix null pointer dereference of pointer perfmon
@ 2022-04-26 12:58 ` Melissa Wen
0 siblings, 0 replies; 4+ messages in thread
From: Melissa Wen @ 2022-04-26 12:58 UTC (permalink / raw)
To: Juan A. Suárez
Cc: Emma Anholt, David Airlie, kernel-janitors, linux-kernel,
dri-devel, Colin Ian King
[-- Attachment #1: Type: text/plain, Size: 472 bytes --]
On 04/25, Juan A. Suárez wrote:
> On Sun, 2022-04-24 at 19:35 +0100, Colin Ian King wrote:
> > In the unlikely event that pointer perfmon is null the WARN_ON return
> > path
> > occurs after the pointer has already been deferenced. Fix this by
> > only
> > dereferencing perfmon after it has been null checked.
> >
>
> Good catch!
>
> Reviewed-by: Juan A. Suarez <jasuarez@igalia.com>
Applied to drm-misc-next.
Thanks,
Melissa
>
>
> J.A.
>
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^ permalink raw reply [flat|nested] 4+ messages in thread
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2022-04-24 18:35 [PATCH] drm/v3d: Fix null pointer dereference of pointer perfmon Colin Ian King
2022-04-25 7:10 ` Juan A. Suárez
2022-04-26 12:58 ` Melissa Wen
2022-04-26 12:58 ` Melissa Wen
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