Hi Xie, First bad commit (maybe != root cause): tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master head: 79e06c4c4950be2abd8ca5d2428a8c915aa62c24 commit: c8a6153b6c59d95c0e091f053f6f180952ade91e vduse: Introduce VDUSE - vDPA Device in Userspace config: arm-randconfig-m031-20220116 (https://download.01.org/0day-ci/archive/20220117/202201171409.rqbXNHlz-lk...) compiler: arm-linux-gnueabi-gcc (GCC) 11.2.0 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/vdpa/vdpa_user/iova_domain.c:305 vduse_domain_alloc_iova() warn: should 'iova_pfn << shift' be a 64 bit type? vim +305 drivers/vdpa/vdpa_user/iova_domain.c 8c773d53fb7b64 Xie Yongji 2021-08-31 287 static dma_addr_t 8c773d53fb7b64 Xie Yongji 2021-08-31 288 vduse_domain_alloc_iova(struct iova_domain *iovad, 8c773d53fb7b64 Xie Yongji 2021-08-31 289 unsigned long size, unsigned long limit) 8c773d53fb7b64 Xie Yongji 2021-08-31 290 { 8c773d53fb7b64 Xie Yongji 2021-08-31 291 unsigned long shift = iova_shift(iovad); 8c773d53fb7b64 Xie Yongji 2021-08-31 292 unsigned long iova_len = iova_align(iovad, size) >> shift; 8c773d53fb7b64 Xie Yongji 2021-08-31 293 unsigned long iova_pfn; 8c773d53fb7b64 Xie Yongji 2021-08-31 294 8c773d53fb7b64 Xie Yongji 2021-08-31 295 /* 8c773d53fb7b64 Xie Yongji 2021-08-31 296 * Freeing non-power-of-two-sized allocations back into the IOVA caches 8c773d53fb7b64 Xie Yongji 2021-08-31 297 * will come back to bite us badly, so we have to waste a bit of space 8c773d53fb7b64 Xie Yongji 2021-08-31 298 * rounding up anything cacheable to make sure that can't happen. The 8c773d53fb7b64 Xie Yongji 2021-08-31 299 * order of the unadjusted size will still match upon freeing. 8c773d53fb7b64 Xie Yongji 2021-08-31 300 */ 8c773d53fb7b64 Xie Yongji 2021-08-31 301 if (iova_len < (1 << (IOVA_RANGE_CACHE_MAX_SIZE - 1))) 8c773d53fb7b64 Xie Yongji 2021-08-31 302 iova_len = roundup_pow_of_two(iova_len); 8c773d53fb7b64 Xie Yongji 2021-08-31 303 iova_pfn = alloc_iova_fast(iovad, iova_len, limit >> shift, true); 8c773d53fb7b64 Xie Yongji 2021-08-31 304 8c773d53fb7b64 Xie Yongji 2021-08-31 @305 return iova_pfn << shift; I feel like iova_pfn should probably be declared as dma_addr_t?