From 6f81b2d047c59eb77cd04795a44245d6a52cdaec Mon Sep 17 00:00:00 2001
From: limingyu <limingyu@uniontech.com>
Date: Wed, 22 Apr 2020 17:01:19 +0800
Subject: [PATCH] drm/amdgpu: Init data to avoid oops while reading pp_num_states.
Git-commit: 6f81b2d047c59eb77cd04795a44245d6a52cdaec
Patch-mainline: v5.8-rc1
References: git-fixes
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>
Acked-by: Takashi Iwai <tiwai@suse.de>
---
drivers/gpu/drm/amd/amdgpu/amdgpu_pm.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_pm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_pm.c
@@ -417,8 +417,11 @@ static ssize_t amdgpu_get_pp_num_states(
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++)