[bug report] drm/amdgpu: Multi-GPU DPC recovery support

[Dan Carpenter]

Hello Ce Sun,

Commit 8ba904f54148 ("drm/amdgpu: Multi-GPU DPC recovery support")
from Mar 21, 2025 (linux-next), leads to the following Smatch static
checker warning:

	drivers/gpu/drm/amd/amdgpu/amdgpu_device.c:6820 amdgpu_pci_slot_reset()
	warn: iterator used outside loop: 'tmp_adev'

drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
    6753 pci_ers_result_t amdgpu_pci_slot_reset(struct pci_dev *pdev)
    6754 {
    6755         struct drm_device *dev = pci_get_drvdata(pdev);
    6756         struct amdgpu_device *adev = drm_to_adev(dev);
    6757         struct amdgpu_reset_context reset_context;
    6758         struct amdgpu_device *tmp_adev = NULL;
    6759         struct amdgpu_hive_info *hive = NULL;
    6760         struct list_head device_list;
    6761         int r = 0, i;
    6762         u32 memsize;
    6763 
    6764         /* PCI error slot reset should be skipped During RAS recovery */
    6765         if ((amdgpu_ip_version(adev, GC_HWIP, 0) == IP_VERSION(9, 4, 3) ||
    6766             amdgpu_ip_version(adev, GC_HWIP, 0) == IP_VERSION(9, 4, 4)) &&
    6767             amdgpu_ras_in_recovery(adev))
    6768                 return PCI_ERS_RESULT_RECOVERED;
    6769 
    6770         dev_info(adev->dev, "PCI error: slot reset callback!!\n");
    6771 
    6772         memset(&reset_context, 0, sizeof(reset_context));
    6773 
    6774         /* wait for asic to come out of reset */
    6775         msleep(700);
    6776 
    6777         /* Restore PCI confspace */
    6778         amdgpu_device_load_pci_state(pdev);
    6779 
    6780         /* confirm  ASIC came out of reset */
    6781         for (i = 0; i < adev->usec_timeout; i++) {
    6782                 memsize = amdgpu_asic_get_config_memsize(adev);
    6783 
    6784                 if (memsize != 0xffffffff)
    6785                         break;
    6786                 udelay(1);
    6787         }
    6788         if (memsize == 0xffffffff) {
    6789                 r = -ETIME;
    6790                 goto out;
    6791         }
    6792 
    6793         reset_context.method = AMD_RESET_METHOD_NONE;
    6794         reset_context.reset_req_dev = adev;
    6795         set_bit(AMDGPU_NEED_FULL_RESET, &reset_context.flags);
    6796         set_bit(AMDGPU_SKIP_COREDUMP, &reset_context.flags);
    6797         INIT_LIST_HEAD(&device_list);
    6798 
    6799         hive = amdgpu_get_xgmi_hive(adev);
    6800         if (hive) {
    6801                 mutex_lock(&hive->hive_lock);
    6802                 reset_context.hive = hive;
    6803                 list_for_each_entry(tmp_adev, &hive->device_list, gmc.xgmi.head) {
    6804                         tmp_adev->pcie_reset_ctx.in_link_reset = true;
    6805                         list_add_tail(&tmp_adev->reset_list, &device_list);
    6806                 }

tmp_adev is an invalid non-NULL pointer.

    6807         } else {
    6808                 set_bit(AMDGPU_SKIP_HW_RESET, &reset_context.flags);
    6809                 list_add_tail(&adev->reset_list, &device_list);
    6810         }
    6811 
    6812         r = amdgpu_device_asic_reset(adev, &device_list, &reset_context);
    6813 out:
    6814         if (!r) {
    6815                 if (amdgpu_device_cache_pci_state(adev->pdev))
    6816                         pci_restore_state(adev->pdev);
    6817                 dev_info(adev->dev, "PCIe error recovery succeeded\n");
    6818         } else {
    6819                 dev_err(adev->dev, "PCIe error recovery failed, err:%d\n", r);
--> 6820                 if (tmp_adev) {

This looks like it might have been intentional but it would be more
readable to check if (hive) {

    6821                         list_for_each_entry(tmp_adev, &device_list, reset_list)
    6822                                 amdgpu_device_unset_mp1_state(tmp_adev);
    6823                         amdgpu_device_unlock_reset_domain(adev->reset_domain);
    6824                 }
    6825         }
    6826 
    6827         if (hive) {
    6828                 mutex_unlock(&hive->hive_lock);
    6829                 amdgpu_put_xgmi_hive(hive);
    6830         }
    6831 
    6832         return r ? PCI_ERS_RESULT_DISCONNECT : PCI_ERS_RESULT_RECOVERED;
    6833 }

regards,
dan carpenter