[kbuild-all] Re: [PATCH v4 6/6] dma-iommu: Pass iova len for IOVA domain init

On 19/07/2021 08:58, Dan Carpenter wrote: > Hi John, > > url: > https://github.com/0day-ci/linux/commits/John-Garry/iommu-Allow-IOVA-rcac... > > base:   https://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu.git > next > config: ia64-randconfig-m031-20210714 (attached as .config) > compiler: ia64-linux-gcc (GCC) 9.3.0 > > If you fix the issue, kindly add following tag as appropriate > Reported-by: kernel test robot <lkp(a)intel.com&gt; > Reported-by: Dan Carpenter <dan.carpenter(a)oracle.com&gt; > > smatch warnings: > drivers/iommu/dma-iommu.c:384 iommu_dma_init_domain() warn: variable > dereferenced before check 'dev' (see line 374) > thanks for the notice > vim +/dev +384 drivers/iommu/dma-iommu.c > > 06d60728ff5c01 Christoph Hellwig     2019-05-20  332  static int > iommu_dma_init_domain(struct iommu_domain *domain, dma_addr_t base, > ac6d704679d343 Jean-Philippe Brucker 2021-06-18  333 > dma_addr_t limit, struct device *dev) > 0db2e5d18f76a6 Robin Murphy          2015-10-01  334  { > fdbe574eb69312 Robin Murphy          2017-01-19  335      struct > iommu_dma_cookie *cookie = domain->iova_cookie; > c61a4633a56aaa Shaokun Zhang         2019-01-24  336      unsigned > long order, base_pfn; > 6b0c54e7f27159 Yunsheng Lin          2019-08-24  337      struct > iova_domain *iovad; > de4ba360c3e4ed John Garry            2021-07-14  338      size_t > max_opt_dma_size; > de4ba360c3e4ed John Garry            2021-07-14  339      unsigned > long iova_len = 0; > 0db2e5d18f76a6 Robin Murphy          2015-10-01  340 > fdbe574eb69312 Robin Murphy          2017-01-19  341      if (!cookie > || cookie->type != IOMMU_DMA_IOVA_COOKIE) > fdbe574eb69312 Robin Murphy          2017-01-19  342          return > -EINVAL; > 0db2e5d18f76a6 Robin Murphy          2015-10-01  343 > 6b0c54e7f27159 Yunsheng Lin          2019-08-24  344      iovad = > &cookie->iovad; > 6b0c54e7f27159 Yunsheng Lin          2019-08-24  345 > 0db2e5d18f76a6 Robin Murphy          2015-10-01  346      /* Use the > smallest supported page size for IOVA granularity */ > d16e0faab911cc Robin Murphy          2016-04-07  347      order = > __ffs(domain->pgsize_bitmap); > 0db2e5d18f76a6 Robin Murphy          2015-10-01  348      base_pfn = > max_t(unsigned long, 1, base >> order); > 0db2e5d18f76a6 Robin Murphy          2015-10-01  349 > 0db2e5d18f76a6 Robin Murphy          2015-10-01  350      /* Check the > domain allows at least some access to the device... */ > 0db2e5d18f76a6 Robin Murphy          2015-10-01  351      if > (domain->geometry.force_aperture) { > 0db2e5d18f76a6 Robin Murphy          2015-10-01  352          if (base > > domain->geometry.aperture_end || > ac6d704679d343 Jean-Philippe Brucker 2021-06-18  353 > limit < domain->geometry.aperture_start) { > 0db2e5d18f76a6 Robin Murphy          2015-10-01  354 > pr_warn("specified DMA range outside IOMMU capability\n"); > 0db2e5d18f76a6 Robin Murphy          2015-10-01  355 > return -EFAULT; > 0db2e5d18f76a6 Robin Murphy          2015-10-01  356          } > 0db2e5d18f76a6 Robin Murphy          2015-10-01  357          /* > ...then finally give it a kicking to make sure it fits */ > 0db2e5d18f76a6 Robin Murphy          2015-10-01  358          base_pfn > = max_t(unsigned long, base_pfn, > 0db2e5d18f76a6 Robin Murphy          2015-10-01  359 > domain->geometry.aperture_start >> order); > 0db2e5d18f76a6 Robin Murphy          2015-10-01  360      } > 0db2e5d18f76a6 Robin Murphy          2015-10-01  361 > f51d7bb79c1124 Robin Murphy          2017-01-16  362      /* start_pfn > is always nonzero for an already-initialised domain */ > 0db2e5d18f76a6 Robin Murphy          2015-10-01  363      if > (iovad->start_pfn) { > 0db2e5d18f76a6 Robin Murphy          2015-10-01  364          if (1UL > << order != iovad->granule || > f51d7bb79c1124 Robin Murphy          2017-01-16  365 > base_pfn != iovad->start_pfn) { > 0db2e5d18f76a6 Robin Murphy          2015-10-01  366 > pr_warn("Incompatible range for DMA domain\n"); > 0db2e5d18f76a6 Robin Murphy          2015-10-01  367 > return -EFAULT; > 0db2e5d18f76a6 Robin Murphy          2015-10-01  368          } > 7c1b058c8b5a31 Robin Murphy          2017-03-16  369 > 7c1b058c8b5a31 Robin Murphy          2017-03-16  370          return 0; > 0db2e5d18f76a6 Robin Murphy          2015-10-01  371      } > 7c1b058c8b5a31 Robin Murphy          2017-03-16  372 > de4ba360c3e4ed John Garry            2021-07-14  373 > de4ba360c3e4ed John Garry            2021-07-14 @374 > max_opt_dma_size = iommu_group_get_max_opt_dma_size(dev->iommu_group); > > ^^^^^^^^^^^^^^^^ > New unchecked dereference > > de4ba360c3e4ed John Garry            2021-07-14  375      if > (max_opt_dma_size) { > de4ba360c3e4ed John Garry            2021-07-14  376          unsigned > long shift = __ffs(1UL << order); > de4ba360c3e4ed John Garry            2021-07-14  377 > de4ba360c3e4ed John Garry            2021-07-14  378          iova_len > = max_opt_dma_size >> shift; > de4ba360c3e4ed John Garry            2021-07-14  379          iova_len > = roundup_pow_of_two(iova_len); > de4ba360c3e4ed John Garry            2021-07-14  380      } > de4ba360c3e4ed John Garry            2021-07-14  381 > de4ba360c3e4ed John Garry            2021-07-14  382 > init_iova_domain(iovad, 1UL << order, base_pfn, iova_len); > 2da274cdf998a1 Zhen Lei              2018-09-20  383 > 82c3cefb9f1652 Lu Baolu              2021-02-25 @384      if > (!cookie->fq_domain && (!dev || !dev_is_untrusted(dev)) && > > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ > > > a250c23f15c21c Robin Murphy          2021-04-01  385 > domain->ops->flush_iotlb_all && !iommu_get_dma_strict(domain)) { > b34e9b0de3c411 Tom Murphy            2020-09-10  386          if > (init_iova_flush_queue(iovad, iommu_dma_flush_iotlb_all, > 2a2b8eaa5b2566 Tom Murphy            2020-11-24 > 387                        iommu_dma_entry_dtor)) > b34e9b0de3c411 Tom Murphy            2020-09-10  388 > pr_warn("iova flush queue initialization failed\n"); > b34e9b0de3c411 Tom Murphy            2020-09-10  389          else > 2da274cdf998a1 Zhen Lei              2018-09-20  390 > cookie->fq_domain = domain; > 2da274cdf998a1 Zhen Lei              2018-09-20  391      } > 2da274cdf998a1 Zhen Lei              2018-09-20  392 > 7c1b058c8b5a31 Robin Murphy          2017-03-16  393      if (!dev) >                                                              ^^^^ > Old code has checks for NULL > I doubt that in practice we need this check. Function iommu_dma_init_domain() is only called by iommu_setup_dma_ops(). Furthermore, iommu_setup_dma_ops() calls iommu_get_domain_for_dev(dev), which cannot safely handle dev == NULL for when we call iommu_dma_init_domain() there. As such, the dev == NULL checks in iommu_dma_init_domain() are effectively redundant.