From dc915275ea5e7e476d174f84cb7674a1e69273d3 Mon Sep 17 00:00:00 2001 From: Srinivasan Shanmugam Date: Mon, 20 Jan 2025 17:57:04 +0530 Subject: [PATCH 1643/5403] drm/amd/amdgpu: Prevent null pointer dereference in GPU bandwidth calculation MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit If the parent is NULL, adev->pdev is used to retrieve the PCIe speed and width, ensuring that the function can still determine these capabilities from the device itself. Fixes the below: 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 } Fixes: 757e8b951ce2 ("drm/amdgpu: cache gpu pcie link width") Cc: Christian König Cc: Alex Deucher Reported-by: Dan Carpenter Signed-off-by: Srinivasan Shanmugam Suggested-by: Lijo Lazar Reviewed-by: Lijo Lazar Reviewed-by: Christian König Signed-off-by: Alex Deucher --- drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c index e5f09d8a5052..d100bb7a137c 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c @@ -6190,8 +6190,8 @@ static void amdgpu_device_gpu_bandwidth(struct amdgpu_device *adev, } } else { /* use the device itself */ - *speed = pcie_get_speed_cap(parent); - *width = pcie_get_width_cap(parent); + *speed = pcie_get_speed_cap(adev->pdev); + *width = pcie_get_width_cap(adev->pdev); } } -- 2.54.0