From: limingyu limingyu@uniontech.com
[ Upstream commit 6f81b2d047c59eb77cd04795a44245d6a52cdaec ]
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 Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/gpu/drm/amd/amdgpu/amdgpu_pm.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_pm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_pm.c index 51263b8d94b1..c8008b956363 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_pm.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_pm.c @@ -416,8 +416,11 @@ 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)); + }
buf_len = snprintf(buf, PAGE_SIZE, "states: %d\n", data.nums); for (i = 0; i < data.nums; i++)