2023-10-27 17:28:42

by Harshit Mogalapalli

[permalink] [raw]
Subject: [PATCH v2] i915/perf: Fix NULL deref bugs with drm_dbg() calls

When i915 perf interface is not available dereferencing it will lead to
NULL dereferences.

As returning -ENOTSUPP is pretty clear return when perf interface is not
available.

Fixes: 2fec539112e8 ("i915/perf: Replace DRM_DEBUG with driver specific drm_dbg call")
Suggested-by: Tvrtko Ursulin <[email protected]>
Signed-off-by: Harshit Mogalapalli <[email protected]>
---
v1 --> v2: Remove the debug calls as they don't add much value and
-ENOTSUPP is a good enough return value.
---
drivers/gpu/drm/i915/i915_perf.c | 15 +++------------
1 file changed, 3 insertions(+), 12 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_perf.c b/drivers/gpu/drm/i915/i915_perf.c
index 2f3ecd7d4804..7b1c8de2f9cb 100644
--- a/drivers/gpu/drm/i915/i915_perf.c
+++ b/drivers/gpu/drm/i915/i915_perf.c
@@ -4227,11 +4227,8 @@ int i915_perf_open_ioctl(struct drm_device *dev, void *data,
u32 known_open_flags;
int ret;

- if (!perf->i915) {
- drm_dbg(&perf->i915->drm,
- "i915 perf interface not available for this system\n");
+ if (!perf->i915)
return -ENOTSUPP;
- }

known_open_flags = I915_PERF_FLAG_FD_CLOEXEC |
I915_PERF_FLAG_FD_NONBLOCK |
@@ -4607,11 +4604,8 @@ int i915_perf_add_config_ioctl(struct drm_device *dev, void *data,
struct i915_oa_reg *regs;
int err, id;

- if (!perf->i915) {
- drm_dbg(&perf->i915->drm,
- "i915 perf interface not available for this system\n");
+ if (!perf->i915)
return -ENOTSUPP;
- }

if (!perf->metrics_kobj) {
drm_dbg(&perf->i915->drm,
@@ -4773,11 +4767,8 @@ int i915_perf_remove_config_ioctl(struct drm_device *dev, void *data,
struct i915_oa_config *oa_config;
int ret;

- if (!perf->i915) {
- drm_dbg(&perf->i915->drm,
- "i915 perf interface not available for this system\n");
+ if (!perf->i915)
return -ENOTSUPP;
- }

if (i915_perf_stream_paranoid && !perfmon_capable()) {
drm_dbg(&perf->i915->drm,
--
2.39.3


2023-10-27 17:38:37

by Tvrtko Ursulin

[permalink] [raw]
Subject: Re: [PATCH v2] i915/perf: Fix NULL deref bugs with drm_dbg() calls


On 27/10/2023 18:28, Harshit Mogalapalli wrote:
> When i915 perf interface is not available dereferencing it will lead to
> NULL dereferences.
>
> As returning -ENOTSUPP is pretty clear return when perf interface is not
> available.
>
> Fixes: 2fec539112e8 ("i915/perf: Replace DRM_DEBUG with driver specific drm_dbg call")
> Suggested-by: Tvrtko Ursulin <[email protected]>
> Signed-off-by: Harshit Mogalapalli <[email protected]>
> ---
> v1 --> v2: Remove the debug calls as they don't add much value and
> -ENOTSUPP is a good enough return value.
> ---
> drivers/gpu/drm/i915/i915_perf.c | 15 +++------------
> 1 file changed, 3 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_perf.c b/drivers/gpu/drm/i915/i915_perf.c
> index 2f3ecd7d4804..7b1c8de2f9cb 100644
> --- a/drivers/gpu/drm/i915/i915_perf.c
> +++ b/drivers/gpu/drm/i915/i915_perf.c
> @@ -4227,11 +4227,8 @@ int i915_perf_open_ioctl(struct drm_device *dev, void *data,
> u32 known_open_flags;
> int ret;
>
> - if (!perf->i915) {
> - drm_dbg(&perf->i915->drm,
> - "i915 perf interface not available for this system\n");
> + if (!perf->i915)
> return -ENOTSUPP;
> - }
>
> known_open_flags = I915_PERF_FLAG_FD_CLOEXEC |
> I915_PERF_FLAG_FD_NONBLOCK |
> @@ -4607,11 +4604,8 @@ int i915_perf_add_config_ioctl(struct drm_device *dev, void *data,
> struct i915_oa_reg *regs;
> int err, id;
>
> - if (!perf->i915) {
> - drm_dbg(&perf->i915->drm,
> - "i915 perf interface not available for this system\n");
> + if (!perf->i915)
> return -ENOTSUPP;
> - }
>
> if (!perf->metrics_kobj) {
> drm_dbg(&perf->i915->drm,
> @@ -4773,11 +4767,8 @@ int i915_perf_remove_config_ioctl(struct drm_device *dev, void *data,
> struct i915_oa_config *oa_config;
> int ret;
>
> - if (!perf->i915) {
> - drm_dbg(&perf->i915->drm,
> - "i915 perf interface not available for this system\n");
> + if (!perf->i915)
> return -ENOTSUPP;
> - }
>
> if (i915_perf_stream_paranoid && !perfmon_capable()) {
> drm_dbg(&perf->i915->drm,

Thanks for re-spinning it so quickly! LGTM.

Reviewed-by: Tvrtko Ursulin <[email protected]>

Regards,

Tvrtko

2023-10-30 12:47:19

by Tvrtko Ursulin

[permalink] [raw]
Subject: Re: [PATCH v2] i915/perf: Fix NULL deref bugs with drm_dbg() calls


On 27/10/2023 18:38, Tvrtko Ursulin wrote:
>
> On 27/10/2023 18:28, Harshit Mogalapalli wrote:
>> When i915 perf interface is not available dereferencing it will lead to
>> NULL dereferences.
>>
>> As returning -ENOTSUPP is pretty clear return when perf interface is not
>> available.
>>
>> Fixes: 2fec539112e8 ("i915/perf: Replace DRM_DEBUG with driver
>> specific drm_dbg call")
>> Suggested-by: Tvrtko Ursulin <[email protected]>
>> Signed-off-by: Harshit Mogalapalli <[email protected]>
>> ---
>> v1 --> v2: Remove the debug calls as they don't add much value and
>> -ENOTSUPP is a good enough return value.
>> ---
>>   drivers/gpu/drm/i915/i915_perf.c | 15 +++------------
>>   1 file changed, 3 insertions(+), 12 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/i915/i915_perf.c
>> b/drivers/gpu/drm/i915/i915_perf.c
>> index 2f3ecd7d4804..7b1c8de2f9cb 100644
>> --- a/drivers/gpu/drm/i915/i915_perf.c
>> +++ b/drivers/gpu/drm/i915/i915_perf.c
>> @@ -4227,11 +4227,8 @@ int i915_perf_open_ioctl(struct drm_device
>> *dev, void *data,
>>       u32 known_open_flags;
>>       int ret;
>> -    if (!perf->i915) {
>> -        drm_dbg(&perf->i915->drm,
>> -            "i915 perf interface not available for this system\n");
>> +    if (!perf->i915)
>>           return -ENOTSUPP;
>> -    }
>>       known_open_flags = I915_PERF_FLAG_FD_CLOEXEC |
>>                  I915_PERF_FLAG_FD_NONBLOCK |
>> @@ -4607,11 +4604,8 @@ int i915_perf_add_config_ioctl(struct
>> drm_device *dev, void *data,
>>       struct i915_oa_reg *regs;
>>       int err, id;
>> -    if (!perf->i915) {
>> -        drm_dbg(&perf->i915->drm,
>> -            "i915 perf interface not available for this system\n");
>> +    if (!perf->i915)
>>           return -ENOTSUPP;
>> -    }
>>       if (!perf->metrics_kobj) {
>>           drm_dbg(&perf->i915->drm,
>> @@ -4773,11 +4767,8 @@ int i915_perf_remove_config_ioctl(struct
>> drm_device *dev, void *data,
>>       struct i915_oa_config *oa_config;
>>       int ret;
>> -    if (!perf->i915) {
>> -        drm_dbg(&perf->i915->drm,
>> -            "i915 perf interface not available for this system\n");
>> +    if (!perf->i915)
>>           return -ENOTSUPP;
>> -    }
>>       if (i915_perf_stream_paranoid && !perfmon_capable()) {
>>           drm_dbg(&perf->i915->drm,
>
> Thanks for re-spinning it so quickly! LGTM.
>
> Reviewed-by: Tvrtko Ursulin <[email protected]>

Now merged to drm-intel-gt-next. Thanks again!

Regards,

Tvrtko