Re: [PATCH v8 11/13] iommu/amd: Don't copy GCR3 table root pointer

From: kbuild test robot
Date: Sun Jul 23 2017 - 18:34:59 EST

Hi Baoquan,

[auto build test WARNING on iommu/next]
[also build test WARNING on v4.13-rc1]
[cannot apply to next-20170721]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url: https://github.com/0day-ci/linux/commits/Baoquan-He/Fix-the-on-flight-DMA-issue-on-system-with-amd-iommu/20170724-060048
base: https://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu.git next
config: x86_64-randconfig-x005-201730 (attached as .config)
compiler: gcc-6 (Debian 6.2.0-3) 6.2.0 20160901
reproduce:
# save the attached .config to linux build tree
make ARCH=x86_64

Note: it may well be a FALSE warning. FWIW you are at least aware of it now.
http://gcc.gnu.org/wiki/Better_Uninitialized_Warnings

All warnings (new ones prefixed by >>):

drivers//iommu/amd_iommu_v2.c: In function 'ppr_notifier':
>> drivers//iommu/amd_iommu_v2.c:566:6: warning: 'ret' may be used uninitialized in this function [-Wmaybe-uninitialized]
int ret;
^~~

vim +/ret +566 drivers//iommu/amd_iommu_v2.c

028eeacc Joerg Roedel 2011-11-24 556
028eeacc Joerg Roedel 2011-11-24 557 static int ppr_notifier(struct notifier_block *nb, unsigned long e, void *data)
028eeacc Joerg Roedel 2011-11-24 558 {
028eeacc Joerg Roedel 2011-11-24 559 struct amd_iommu_fault *iommu_fault;
028eeacc Joerg Roedel 2011-11-24 560 struct pasid_state *pasid_state;
028eeacc Joerg Roedel 2011-11-24 561 struct device_state *dev_state;
028eeacc Joerg Roedel 2011-11-24 562 unsigned long flags;
028eeacc Joerg Roedel 2011-11-24 563 struct fault *fault;
028eeacc Joerg Roedel 2011-11-24 564 bool finish;
49f3c23d Baoquan He 2017-07-21 565 u16 tag, devid;
028eeacc Joerg Roedel 2011-11-24 @566 int ret;
49f3c23d Baoquan He 2017-07-21 567 struct iommu_dev_data *dev_data;
49f3c23d Baoquan He 2017-07-21 568 struct pci_dev *pdev = NULL;
028eeacc Joerg Roedel 2011-11-24 569
028eeacc Joerg Roedel 2011-11-24 570 iommu_fault = data;
028eeacc Joerg Roedel 2011-11-24 571 tag = iommu_fault->tag & 0x1ff;
028eeacc Joerg Roedel 2011-11-24 572 finish = (iommu_fault->tag >> 9) & 1;
028eeacc Joerg Roedel 2011-11-24 573
49f3c23d Baoquan He 2017-07-21 574 devid = iommu_fault->device_id;
49f3c23d Baoquan He 2017-07-21 575 pdev = pci_get_bus_and_slot(PCI_BUS_NUM(devid), devid & 0xff);
49f3c23d Baoquan He 2017-07-21 576 if (!pdev)
49f3c23d Baoquan He 2017-07-21 577 return -ENODEV;
49f3c23d Baoquan He 2017-07-21 578 dev_data = get_dev_data(&pdev->dev);
49f3c23d Baoquan He 2017-07-21 579
49f3c23d Baoquan He 2017-07-21 580 /* In kdump kernel pci dev is not initialized yet -> send INVALID */
49f3c23d Baoquan He 2017-07-21 581 if (translation_pre_enabled(amd_iommu_rlookup_table[devid])
49f3c23d Baoquan He 2017-07-21 582 && dev_data->defer_attach) {
49f3c23d Baoquan He 2017-07-21 583 amd_iommu_complete_ppr(pdev, iommu_fault->pasid,
49f3c23d Baoquan He 2017-07-21 584 PPR_INVALID, tag);
49f3c23d Baoquan He 2017-07-21 585 goto out;
49f3c23d Baoquan He 2017-07-21 586 }
49f3c23d Baoquan He 2017-07-21 587
028eeacc Joerg Roedel 2011-11-24 588 ret = NOTIFY_DONE;
028eeacc Joerg Roedel 2011-11-24 589 dev_state = get_device_state(iommu_fault->device_id);
028eeacc Joerg Roedel 2011-11-24 590 if (dev_state == NULL)
028eeacc Joerg Roedel 2011-11-24 591 goto out;
028eeacc Joerg Roedel 2011-11-24 592
028eeacc Joerg Roedel 2011-11-24 593 pasid_state = get_pasid_state(dev_state, iommu_fault->pasid);
53d340ef Joerg Roedel 2014-07-08 594 if (pasid_state == NULL || pasid_state->invalid) {
028eeacc Joerg Roedel 2011-11-24 595 /* We know the device but not the PASID -> send INVALID */
028eeacc Joerg Roedel 2011-11-24 596 amd_iommu_complete_ppr(dev_state->pdev, iommu_fault->pasid,
028eeacc Joerg Roedel 2011-11-24 597 PPR_INVALID, tag);
028eeacc Joerg Roedel 2011-11-24 598 goto out_drop_state;
028eeacc Joerg Roedel 2011-11-24 599 }
028eeacc Joerg Roedel 2011-11-24 600
028eeacc Joerg Roedel 2011-11-24 601 spin_lock_irqsave(&pasid_state->lock, flags);
028eeacc Joerg Roedel 2011-11-24 602 atomic_inc(&pasid_state->pri[tag].inflight);
028eeacc Joerg Roedel 2011-11-24 603 if (finish)
028eeacc Joerg Roedel 2011-11-24 604 pasid_state->pri[tag].finish = true;
028eeacc Joerg Roedel 2011-11-24 605 spin_unlock_irqrestore(&pasid_state->lock, flags);
028eeacc Joerg Roedel 2011-11-24 606
028eeacc Joerg Roedel 2011-11-24 607 fault = kzalloc(sizeof(*fault), GFP_ATOMIC);
028eeacc Joerg Roedel 2011-11-24 608 if (fault == NULL) {
028eeacc Joerg Roedel 2011-11-24 609 /* We are OOM - send success and let the device re-fault */
028eeacc Joerg Roedel 2011-11-24 610 finish_pri_tag(dev_state, pasid_state, tag);
028eeacc Joerg Roedel 2011-11-24 611 goto out_drop_state;
028eeacc Joerg Roedel 2011-11-24 612 }
028eeacc Joerg Roedel 2011-11-24 613
028eeacc Joerg Roedel 2011-11-24 614 fault->dev_state = dev_state;
028eeacc Joerg Roedel 2011-11-24 615 fault->address = iommu_fault->address;
028eeacc Joerg Roedel 2011-11-24 616 fault->state = pasid_state;
028eeacc Joerg Roedel 2011-11-24 617 fault->tag = tag;
028eeacc Joerg Roedel 2011-11-24 618 fault->finish = finish;
b00675b8 Alexey Skidanov 2014-07-08 619 fault->pasid = iommu_fault->pasid;
028eeacc Joerg Roedel 2011-11-24 620 fault->flags = iommu_fault->flags;
028eeacc Joerg Roedel 2011-11-24 621 INIT_WORK(&fault->work, do_fault);
028eeacc Joerg Roedel 2011-11-24 622
028eeacc Joerg Roedel 2011-11-24 623 queue_work(iommu_wq, &fault->work);
028eeacc Joerg Roedel 2011-11-24 624
028eeacc Joerg Roedel 2011-11-24 625 ret = NOTIFY_OK;
028eeacc Joerg Roedel 2011-11-24 626
028eeacc Joerg Roedel 2011-11-24 627 out_drop_state:
dc88db7e Joerg Roedel 2014-07-08 628
dc88db7e Joerg Roedel 2014-07-08 629 if (ret != NOTIFY_OK && pasid_state)
dc88db7e Joerg Roedel 2014-07-08 630 put_pasid_state(pasid_state);
dc88db7e Joerg Roedel 2014-07-08 631
028eeacc Joerg Roedel 2011-11-24 632 put_device_state(dev_state);
028eeacc Joerg Roedel 2011-11-24 633
028eeacc Joerg Roedel 2011-11-24 634 out:
028eeacc Joerg Roedel 2011-11-24 635 return ret;
028eeacc Joerg Roedel 2011-11-24 636 }
028eeacc Joerg Roedel 2011-11-24 637

:::::: The code at line 566 was first introduced by commit
:::::: 028eeacc412a8bebf6711e58629b0cab56a9ba87 iommu/amd: Implement IO page-fault handler

:::::: TO: Joerg Roedel <joerg.roedel@xxxxxxx>
:::::: CC: Joerg Roedel <joerg.roedel@xxxxxxx>

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