Subject: Re: [PATCH v1 2/2] iommu/arm-smmu-v3: Recover ATC invalidate timeouts

From: kernel test robot <[email-masked]>
Date: Fri, 6 Mar 2026 10:35:17 +0800

Hi Nicolin,

kernel test robot noticed the following build errors:

[auto build test ERROR on pci/next]
[also build test ERROR on pci/for-linus rafael-pm/linux-next rafael-pm/bleeding-edge soc/for-next linus/master v7.0-rc2 next-20260305]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Nicolin-Chen/iommu-Do-not-call-pci_dev_reset_iommu_done-unless-reset-succeeds/20260305-132923
base:   https://git.kernel.org/pub/scm/linux/kernel/git/pci/pci.git next
patch link:    https://lore.kernel.org/r/ca7ab934bf0f433b62a5c15d42241632c4cb9366.1772686998.git.nicolinc%40nvidia.com
patch subject: [PATCH v1 2/2] iommu/arm-smmu-v3: Recover ATC invalidate timeouts
config: arm64-randconfig-001-20260306 (https://download.01.org/0day-ci/archive/20260306/[email-masked]/config)
compiler: aarch64-linux-gcc (GCC) 12.5.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260306/[email-masked]/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <[email-masked]>
| Closes: https://lore.kernel.org/oe-kbuild-all/[email-masked]/

All errors (new ones prefixed by >>):

   drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c: In function 'arm_smmu_atc_recovery_worker':
>> drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c:467:9: error: implicit declaration of function 'pci_dev_lock'; did you mean 'pci_dev_get'? [-Werror=implicit-function-declaration]
     467 |         pci_dev_lock(pdev);
         |         ^~~~~~~~~~~~
         |         pci_dev_get
>> drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c:471:9: error: implicit declaration of function 'pci_dev_unlock'; did you mean 'inode_unlock'? [-Werror=implicit-function-declaration]
     471 |         pci_dev_unlock(pdev);
         |         ^~~~~~~~~~~~~~
         |         inode_unlock
>> drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c:480:14: error: implicit declaration of function 'pci_reset_function' [-Werror=implicit-function-declaration]
     480 |         if (!pci_reset_function(pdev)) {
         |              ^~~~~~~~~~~~~~~~~~
   cc1: some warnings being treated as errors

vim +467 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c

   431	
   432	static void arm_smmu_atc_recovery_worker(struct work_struct *work)
   433	{
   434		struct arm_smmu_atc_recovery_param *param =
   435			container_of(work, struct arm_smmu_atc_recovery_param, work);
   436		struct pci_dev *pdev;
   437	
   438		scoped_guard(mutex, &param->smmu->streams_mutex) {
   439			struct arm_smmu_master *master;
   440	
   441			master = arm_smmu_find_master(param->smmu, param->sid);
   442			if (!master || WARN_ON(!dev_is_pci(master->dev)))
   443				goto free_param;
   444			pdev = to_pci_dev(master->dev);
   445			pci_dev_get(pdev);
   446		}
   447	
   448		scoped_guard(spinlock_irqsave, &param->smmu->atc_recovery.lock) {
   449			struct arm_smmu_atc_recovery_param *e;
   450	
   451			list_for_each_entry(e, &param->smmu->atc_recovery.list, node) {
   452				/* Device is already being recovered */
   453				if (e->pdev == pdev)
   454					goto put_pdev;
   455			}
   456			param->pdev = pdev;
   457			list_add(&param->node, &param->smmu->atc_recovery.list);
   458		}
   459	
   460		/*
   461		 * Stop DMA (PCI) and block ATS (IOMMU) immediately, to prevent memory
   462		 * corruption. This must take pci_dev_lock to prevent any racy unplug.
   463		 *
   464		 * If pci_dev_reset_iommu_prepare() fails, pci_reset_function will call
   465		 * it again internally.
   466		 */
 > 467		pci_dev_lock(pdev);
   468		pci_clear_master(pdev);
   469		if (pci_dev_reset_iommu_prepare(pdev))
   470			pci_err(pdev, "failed to block ATS!\n");
 > 471		pci_dev_unlock(pdev);
   472	
   473		/*
   474		 * ATC timeout indicates the device has stopped responding to coherence
   475		 * protocol requests. The only safe recovery is a reset to flush stale
   476		 * cached translations. Note that pci_reset_function() internally calls
   477		 * pci_dev_reset_iommu_prepare/done() as well and ensures to block ATS
   478		 * if PCI-level reset fails.
   479		 */
 > 480		if (!pci_reset_function(pdev)) {
   481			/*
   482			 * If reset succeeds, set BME back. Otherwise, fence the system
   483			 * from a faulty device, in which case user will have to replug
   484			 * the device to invoke pci_set_master().
   485			 */
   486			pci_dev_lock(pdev);
   487			pci_set_master(pdev);
   488			pci_dev_unlock(pdev);
   489		}
   490		scoped_guard(spinlock_irqsave, &param->smmu->atc_recovery.lock)
   491			list_del(&param->node);
   492	put_pdev:
   493		pci_dev_put(pdev);
   494	free_param:
   495		kfree(param);
   496	}
   497	

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