Hello Alex Deucher,
Commit 8fae3b201fee ("drm/amdgpu: cache gpu pcie link width") from
Jan 6, 2025 (linux-next), leads to the following Smatch static
checker warning:
drivers/gpu/drm/amd/amdgpu/amdgpu_device.c:6193 amdgpu_device_gpu_bandwidth()
error: we previously assumed 'parent' could be null (see line 6180)
drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
6170 static void amdgpu_device_gpu_bandwidth(struct amdgpu_device *adev,
6171 enum pci_bus_speed *speed,
6172 enum pcie_link_width *width)
6173 {
6174 struct pci_dev *parent = adev->pdev;
6175
6176 if (!speed || !width)
6177 return;
6178
6179 parent = pci_upstream_bridge(parent);
6180 if (parent && parent->vendor == PCI_VENDOR_ID_ATI) {
^^^^^^
If parent is NULL
6181 /* use the upstream/downstream switches internal to dGPU */
6182 *speed = pcie_get_speed_cap(parent);
6183 *width = pcie_get_width_cap(parent);
6184 while ((parent = pci_upstream_bridge(parent))) {
6185 if (parent->vendor == PCI_VENDOR_ID_ATI) {
6186 /* use the upstream/downstream switches internal to dGPU */
6187 *speed = pcie_get_speed_cap(parent);
6188 *width = pcie_get_width_cap(parent);
6189 }
6190 }
6191 } else {
6192 /* use the device itself */
--> 6193 *speed = pcie_get_speed_cap(parent);
^^^^^^
Then we are toasted here.
6194 *width = pcie_get_width_cap(parent);
6195 }
6196 }
regards,
dan carpenter
