CC: kbuild-all(a)lists.01.org CC: linux-kernel(a)vger.kernel.org TO: Mike Rapoport <rppt(a)linux.ibm.com&gt; CC: Andrew Morton <akpm(a)linux-foundation.org&gt; CC: Linux Memory Management List <linux-mm(a)kvack.org&gt; tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master head: 0513e464f9007b70b96740271a948ca5ab6e7dd7 commit: 050b2da268f8fc4f8123f6462c430a61547b2f7b arc: use FLATMEM with freeing of unused memory map instead of DISCONTIGMEM date: 10 months ago :::::: branch date: 18 hours ago :::::: commit date: 10 months ago config: arc-randconfig-m031-20210928 (attached as .config) compiler: arc-elf-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; New smatch warnings: arch/arc/mm/dma.c:30 arch_dma_prep_coherent() warn: should '((page - mem_map) + arch_pfn_offset) << 13' be a 64 bit type? kernel/dma/direct.c:90 __dma_direct_alloc_pages() warn: should '((page - mem_map) + arch_pfn_offset) << 13' be a 64 bit type? kernel/dma/direct.c:129 dma_direct_alloc_from_pool() warn: should '((page - mem_map) + arch_pfn_offset) << 13' be a 64 bit type? kernel/dma/direct.c:152 dma_direct_alloc() warn: should '((page - mem_map) + arch_pfn_offset) << 13' be a 64 bit type? kernel/dma/direct.c:310 dma_direct_alloc_pages() warn: should '((page - mem_map) + arch_pfn_offset) << 13' be a 64 bit type? kernel/dma/pool.c:123 atomic_pool_expand() warn: should '((page - mem_map) + arch_pfn_offset) << 13' be a 64 bit type? Old smatch warnings: arch/arc/include/asm/thread_info.h:65 current_thread_info() error: uninitialized symbol 'sp'. arch/arc/include/asm/thread_info.h:65 current_thread_info() error: uninitialized symbol 'sp'. vim +30 arch/arc/mm/dma.c 1162b0701b14ba Vineet Gupta 2013-01-18 9 2820a708d5a321 Eugeniy Paltsev 2018-07-30 10 /* f73c9045343931 Christoph Hellwig 2019-06-14 11 * ARCH specific callbacks for generic noncoherent DMA ops 2820a708d5a321 Eugeniy Paltsev 2018-07-30 12 * - hardware IOC not available (or "dma-coherent" not set for device in DT) 2820a708d5a321 Eugeniy Paltsev 2018-07-30 13 * - But still handle both coherent and non-coherent requests from caller 2820a708d5a321 Eugeniy Paltsev 2018-07-30 14 * 2820a708d5a321 Eugeniy Paltsev 2018-07-30 15 * For DMA coherent hardware (IOC) generic code suffices 2820a708d5a321 Eugeniy Paltsev 2018-07-30 16 */ 1162b0701b14ba Vineet Gupta 2013-01-18 17 f73c9045343931 Christoph Hellwig 2019-06-14 18 void arch_dma_prep_coherent(struct page *page, size_t size) f73c9045343931 Christoph Hellwig 2019-06-14 19 { 795f4558562fd5 Vineet Gupta 2015-04-03 20 /* 795f4558562fd5 Vineet Gupta 2015-04-03 21 * Evict any existing L1 and/or L2 lines for the backing page 795f4558562fd5 Vineet Gupta 2015-04-03 22 * in case it was used earlier as a normal "cached" page. 795f4558562fd5 Vineet Gupta 2015-04-03 23 * Yeah this bit us - STAR 9000898266 795f4558562fd5 Vineet Gupta 2015-04-03 24 * 795f4558562fd5 Vineet Gupta 2015-04-03 25 * Although core does call flush_cache_vmap(), it gets kvaddr hence 795f4558562fd5 Vineet Gupta 2015-04-03 26 * can't be used to efficiently flush L1 and/or L2 which need paddr 795f4558562fd5 Vineet Gupta 2015-04-03 27 * Currently flush_cache_vmap nukes the L1 cache completely which 795f4558562fd5 Vineet Gupta 2015-04-03 28 * will be optimized as a separate commit 795f4558562fd5 Vineet Gupta 2015-04-03 29 */ f73c9045343931 Christoph Hellwig 2019-06-14 @30 dma_cache_wback_inv(page_to_phys(page), size); a79a812131b072 Alexey Brodkin 2016-11-03 31 } a79a812131b072 Alexey Brodkin 2016-11-03 32 :::::: The code at line 30 was first introduced by commit :::::: f73c904534393133e7ddbbe5c36bb007f9c2fb7f arc: use the generic remapping allocator for coherent DMA allocations :::::: TO: Christoph Hellwig <hch(a)lst.de&gt; :::::: CC: Christoph Hellwig <hch(a)lst.de&gt; --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org