[PATCH] drm/amdgpu: Fix regression in adjusting power table/profile

[Matt Coffin]

Hello all, I just did some testing with this applied, and while it no
longer returns -EINVAL, running `sudo sh -c 'echo "vc 2 2150 1195" >
/sys/class/drm/card1/device/pp_od_clk_voltage'` results in `sh` spiking
to, and staying at 100% CPU usage, with no indicating information in
`dmesg` from the kernel.

It appeared to work at least ONCE, but potentially not after.

This is not unique to Navi, and caused the problem on a POLARIS10 card
as well.

Sorry for the bad news, and thanks for any insight you may have,
Matt Coffin

On 7/29/20 8:53 PM, Alex Deucher wrote:
> On Wed, Jul 29, 2020 at 10:20 PM Paweł Gronowski <me at woland.xyz> wrote:
>>
>> Regression was introduced in commit 38e0c89a19fd
>> ("drm/amdgpu: Fix NULL dereference in dpm sysfs handlers") which
>> made the set_pp_od_clk_voltage and set_pp_power_profile_mode return
>> -EINVAL for previously valid input. This was caused by an empty
>> string (starting at the \0 character) being passed to the kstrtol.
>>
>> Signed-off-by: Paweł Gronowski <me at woland.xyz>
> 
> Applied.  Thanks!
> 
> Alex
> 
>> ---
>>  drivers/gpu/drm/amd/amdgpu/amdgpu_pm.c | 9 +++++++--
>>  1 file changed, 7 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_pm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_pm.c
>> index ebb8a28ff002..cbf623ff03bd 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_pm.c
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_pm.c
>> @@ -778,12 +778,14 @@ static ssize_t amdgpu_set_pp_od_clk_voltage(struct device *dev,
>>                 tmp_str++;
>>         while (isspace(*++tmp_str));
>>
>> -       while ((sub_str = strsep(&tmp_str, delimiter)) != NULL) {
>> +       while ((sub_str = strsep(&tmp_str, delimiter)) && *sub_str) {
>>                 ret = kstrtol(sub_str, 0, &parameter[parameter_size]);
>>                 if (ret)
>>                         return -EINVAL;
>>                 parameter_size++;
>>
>> +               if (!tmp_str)
>> +                       break;
>>                 while (isspace(*tmp_str))
>>                         tmp_str++;
>>         }
>> @@ -1635,11 +1637,14 @@ static ssize_t amdgpu_set_pp_power_profile_mode(struct device *dev,
>>                         i++;
>>                 memcpy(buf_cpy, buf, count-i);
>>                 tmp_str = buf_cpy;
>> -               while ((sub_str = strsep(&tmp_str, delimiter)) != NULL) {
>> +               while ((sub_str = strsep(&tmp_str, delimiter)) && *sub_str) {
>>                         ret = kstrtol(sub_str, 0, &parameter[parameter_size]);
>>                         if (ret)
>>                                 return -EINVAL;
>>                         parameter_size++;
>> +
>> +                       if (!tmp_str)
>> +                               break;
>>                         while (isspace(*tmp_str))
>>                                 tmp_str++;
>>                 }
>> --
>> 2.25.1
>>
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>> amd-gfx at lists.freedesktop.org
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