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drm/amdgpu: Init data to avoid oops while reading pp_num_states.

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For chip like CHIP_OLAND with si enabled(amdgpu.si_support=1),
the amdgpu will expose pp_num_states to the /sys directory.
In this moment, read the pp_num_states file will excute the
amdgpu_get_pp_num_states func. In our case, the data hasn't
been initialized, so the kernel will access some ilegal
address, trigger the segmentfault and system will reboot soon:

    uos@uos-PC:~$ cat /sys/devices/pci0000\:00/0000\:00\:00.0/0000\:01\:00
    .0/pp_num_states

    Message from syslogd@uos-PC at Apr 22 09:26:20 ...
     kernel:[   82.154129] Internal error: Oops: 96000004 [#1] SMP

This patch aims to fix this problem, avoid that reading file
triggers the kernel sementfault.

Signed-off-by: limingyu <limingyu@uniontech.com>
Signed-off-by: zhoubinbin <zhoubinbin@uniontech.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
This commit is contained in:
limingyu 2020-04-22 17:01:19 +08:00 committed by Alex Deucher
parent 00aba6da21
commit 6f81b2d047
1 changed files with 4 additions and 1 deletions
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5
drivers/gpu/drm/amd/amdgpu/amdgpu_pm.c
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@ -444,8 +444,11 @@ static ssize_t amdgpu_get_pp_num_states(struct device *dev,
ret = smu_get_power_num_states(&adev->smu, &data);
if (ret)
return ret;
} else if (adev->powerplay.pp_funcs->get_pp_num_states)
} else if (adev->powerplay.pp_funcs->get_pp_num_states) {
amdgpu_dpm_get_pp_num_states(adev, &data);
} else {
memset(&data, 0, sizeof(data));
}
pm_runtime_mark_last_busy(ddev->dev);
pm_runtime_put_autosuspend(ddev->dev);