On 19/07/2021 08:58, Dan Carpenter wrote: > Hi John, > > url: https://github.com/0day-ci/linux/commits/John-Garry/iommu-Allow-IOVA-rcache-range-be-configured/20210714-184328 > 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 > Reported-by: Dan Carpenter > > 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. > 0db2e5d18f76a6 Robin Murphy 2015-10-01 394 return 0; > 7c1b058c8b5a31 Robin Murphy 2017-03-16 395 > 7c1b058c8b5a31 Robin Murphy 2017-03-16 396 return iova_reserve_iommu_regions(dev, domain); > 0db2e5d18f76a6 Robin Murphy 2015-10-01 397 } > > --- > 0-DAY CI Kernel Test Service, Intel Corporation > https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org > > . > _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu