Hi Keqian, url: https://github.com/0day-ci/linux/commits/Keqian-Zhu/vfio-iommu_type1-Some... base: https://github.com/awilliam/linux-vfio.git next config: x86_64-randconfig-m001-20201215 (attached as .config) compiler: gcc-9 (Debian 9.3.0-15) 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/vfio/vfio_iommu_type1.c:648 vfio_iommu_type1_pin_pages() warn: variable dereferenced before check 'iommu' (see line 640) vim +/iommu +648 drivers/vfio/vfio_iommu_type1.c a54eb55045ae9b3 Kirti Wankhede 2016-11-17 631 static int vfio_iommu_type1_pin_pages(void *iommu_data, 95fc87b44104d9a Kirti Wankhede 2020-05-29 632 struct iommu_group *iommu_group, a54eb55045ae9b3 Kirti Wankhede 2016-11-17 633 unsigned long *user_pfn, a54eb55045ae9b3 Kirti Wankhede 2016-11-17 634 int npage, int prot, a54eb55045ae9b3 Kirti Wankhede 2016-11-17 635 unsigned long *phys_pfn) a54eb55045ae9b3 Kirti Wankhede 2016-11-17 636 { a54eb55045ae9b3 Kirti Wankhede 2016-11-17 637 struct vfio_iommu *iommu = iommu_data; 95fc87b44104d9a Kirti Wankhede 2020-05-29 638 struct vfio_group *group; a54eb55045ae9b3 Kirti Wankhede 2016-11-17 639 int i, j, ret; 2b172c0ea2a6daf Keqian Zhu 2020-12-10 @640 unsigned long pgshift = __ffs(iommu->pgsize_bitmap); ^^^^^^^^^^^^^^^^^^^^ The patch introduces a new dereference. a54eb55045ae9b3 Kirti Wankhede 2016-11-17 641 unsigned long remote_vaddr; 2b172c0ea2a6daf Keqian Zhu 2020-12-10 642 unsigned long bitmap_offset; 2b172c0ea2a6daf Keqian Zhu 2020-12-10 643 unsigned long *bitmap_added; 2b172c0ea2a6daf Keqian Zhu 2020-12-10 644 dma_addr_t iova; a54eb55045ae9b3 Kirti Wankhede 2016-11-17 645 struct vfio_dma *dma; a54eb55045ae9b3 Kirti Wankhede 2016-11-17 646 bool do_accounting; a54eb55045ae9b3 Kirti Wankhede 2016-11-17 647 a54eb55045ae9b3 Kirti Wankhede 2016-11-17 @648 if (!iommu || !user_pfn || !phys_pfn) ^^^^^^ Checked too late. a54eb55045ae9b3 Kirti Wankhede 2016-11-17 649 return -EINVAL; a54eb55045ae9b3 Kirti Wankhede 2016-11-17 650 a54eb55045ae9b3 Kirti Wankhede 2016-11-17 651 /* Supported for v2 version only */ a54eb55045ae9b3 Kirti Wankhede 2016-11-17 652 if (!iommu->v2) a54eb55045ae9b3 Kirti Wankhede 2016-11-17 653 return -EACCES; a54eb55045ae9b3 Kirti Wankhede 2016-11-17 654 a54eb55045ae9b3 Kirti Wankhede 2016-11-17 655 mutex_lock(&iommu->lock); a54eb55045ae9b3 Kirti Wankhede 2016-11-17 656 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org _______________________________________________ kbuild mailing list -- kbuild(a)lists.01.org To unsubscribe send an email to kbuild-leave(a)lists.01.org