[PATCH AUTOSEL 5.15 09/10] drm/amdgpu: Fix cat debugfs amdgpu_regs_didt causes kernel null pointer

Sasha Levin
2023-12-04T20:39:51Z

From: Lu Yao <yaolu@kylinos.cn>

[ Upstream commit 2161e09cd05a50d80736fe397145340d2e8f6c05 ]

For 'AMDGPU_FAMILY_SI' family cards, in 'si_common_early_init' func, init
'didt_rreg' and 'didt_wreg' to 'NULL'. But in func
'amdgpu_debugfs_regs_didt_read/write', using 'RREG32_DIDT' 'WREG32_DIDT'
lacks of relevant judgment. And other 'amdgpu_ip_block_version' that use
these two definitions won't be added for 'AMDGPU_FAMILY_SI'.

So, add null pointer judgment before calling.

Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Lu Yao <yaolu@kylinos.cn>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c | 6 ++++++
1 file changed, 6 insertions(+)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c
index beb199d13451b..632d8df04ef45 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c
@@ -342,6 +342,9 @@ static ssize_t amdgpu_debugfs_regs_didt_read(struct file *f, char __user *buf,
if (size & 0x3 || *pos & 0x3)
return -EINVAL;

+ if (!adev->didt_rreg)
+ return -EOPNOTSUPP;
+
r = pm_runtime_get_sync(adev_to_drm(adev)->dev);
if (r < 0) {
pm_runtime_put_autosuspend(adev_to_drm(adev)->dev);
@@ -401,6 +404,9 @@ static ssize_t amdgpu_debugfs_regs_didt_write(struct file *f, const char __user
if (size & 0x3 || *pos & 0x3)
return -EINVAL;

+ if (!adev->didt_wreg)
+ return -EOPNOTSUPP;
+
r = pm_runtime_get_sync(adev_to_drm(adev)->dev);
if (r < 0) {
pm_runtime_put_autosuspend(adev_to_drm(adev)->dev);
--
2.42.0