Hi Mike, Thank you for the patch! Perhaps something to improve: [auto build test WARNING on vhost/linux-next] [also build test WARNING on v5.9-rc6 next-20200921] [cannot apply to target/for-next] [If your patch is applied to the wrong git tree, kindly drop us a note. And when submitting patch, we suggest to use '--base' as documented in https://git-scm.com/docs/git-format-patch] url: https://github.com/0day-ci/linux/commits/Mike-Christie/vhost-scsi-fixes-a... base: https://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost.git linux-next config: s390-randconfig-r022-20200920 (attached as .config) compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project 4e8c028158b56d9c2142a62464e8e0686bde3584) reproduce (this is a W=1 build): wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross chmod +x ~/bin/make.cross # install s390 cross compiling tool for clang build # apt-get install binutils-s390x-linux-gnu # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=s390 If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; All warnings (new ones prefixed by >>): include/asm-generic/io.h:490:45: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] val = __le32_to_cpu(__raw_readl(PCI_IOBASE + addr)); ~~~~~~~~~~ ^ include/uapi/linux/byteorder/big_endian.h:34:59: note: expanded from macro '__le32_to_cpu' #define __le32_to_cpu(x) __swab32((__force __u32)(__le32)(x)) ^ include/uapi/linux/swab.h:119:21: note: expanded from macro '__swab32' ___constant_swab32(x) : \ ^ include/uapi/linux/swab.h:20:12: note: expanded from macro '___constant_swab32' (((__u32)(x) & (__u32)0x0000ff00UL) << 8) | \ ^ In file included from drivers/vhost/scsi.c:45: In file included from include/uapi/linux/vhost.h:14: In file included from include/uapi/linux/vhost_types.h:16: In file included from include/linux/virtio_config.h:7: In file included from include/linux/virtio.h:7: In file included from include/linux/scatterlist.h:9: In file included from arch/s390/include/asm/io.h:72: include/asm-generic/io.h:490:45: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] val = __le32_to_cpu(__raw_readl(PCI_IOBASE + addr)); ~~~~~~~~~~ ^ include/uapi/linux/byteorder/big_endian.h:34:59: note: expanded from macro '__le32_to_cpu' #define __le32_to_cpu(x) __swab32((__force __u32)(__le32)(x)) ^ include/uapi/linux/swab.h:119:21: note: expanded from macro '__swab32' ___constant_swab32(x) : \ ^ include/uapi/linux/swab.h:21:12: note: expanded from macro '___constant_swab32' (((__u32)(x) & (__u32)0x00ff0000UL) >> 8) | \ ^ In file included from drivers/vhost/scsi.c:45: In file included from include/uapi/linux/vhost.h:14: In file included from include/uapi/linux/vhost_types.h:16: In file included from include/linux/virtio_config.h:7: In file included from include/linux/virtio.h:7: In file included from include/linux/scatterlist.h:9: In file included from arch/s390/include/asm/io.h:72: include/asm-generic/io.h:490:45: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] val = __le32_to_cpu(__raw_readl(PCI_IOBASE + addr)); ~~~~~~~~~~ ^ include/uapi/linux/byteorder/big_endian.h:34:59: note: expanded from macro '__le32_to_cpu' #define __le32_to_cpu(x) __swab32((__force __u32)(__le32)(x)) ^ include/uapi/linux/swab.h:119:21: note: expanded from macro '__swab32' ___constant_swab32(x) : \ ^ include/uapi/linux/swab.h:22:12: note: expanded from macro '___constant_swab32' (((__u32)(x) & (__u32)0xff000000UL) >> 24))) ^ In file included from drivers/vhost/scsi.c:45: In file included from include/uapi/linux/vhost.h:14: In file included from include/uapi/linux/vhost_types.h:16: In file included from include/linux/virtio_config.h:7: In file included from include/linux/virtio.h:7: In file included from include/linux/scatterlist.h:9: In file included from arch/s390/include/asm/io.h:72: include/asm-generic/io.h:490:45: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] val = __le32_to_cpu(__raw_readl(PCI_IOBASE + addr)); ~~~~~~~~~~ ^ include/uapi/linux/byteorder/big_endian.h:34:59: note: expanded from macro '__le32_to_cpu' #define __le32_to_cpu(x) __swab32((__force __u32)(__le32)(x)) ^ include/uapi/linux/swab.h:120:12: note: expanded from macro '__swab32' __fswab32(x)) ^ In file included from drivers/vhost/scsi.c:45: In file included from include/uapi/linux/vhost.h:14: In file included from include/uapi/linux/vhost_types.h:16: In file included from include/linux/virtio_config.h:7: In file included from include/linux/virtio.h:7: In file included from include/linux/scatterlist.h:9: In file included from arch/s390/include/asm/io.h:72: include/asm-generic/io.h:501:33: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] __raw_writeb(value, PCI_IOBASE + addr); ~~~~~~~~~~ ^ include/asm-generic/io.h:511:46: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] __raw_writew(cpu_to_le16(value), PCI_IOBASE + addr); ~~~~~~~~~~ ^ include/asm-generic/io.h:521:46: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] __raw_writel(cpu_to_le32(value), PCI_IOBASE + addr); ~~~~~~~~~~ ^ include/asm-generic/io.h:609:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] readsb(PCI_IOBASE + addr, buffer, count); ~~~~~~~~~~ ^ include/asm-generic/io.h:617:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] readsw(PCI_IOBASE + addr, buffer, count); ~~~~~~~~~~ ^ include/asm-generic/io.h:625:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] readsl(PCI_IOBASE + addr, buffer, count); ~~~~~~~~~~ ^ include/asm-generic/io.h:634:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] writesb(PCI_IOBASE + addr, buffer, count); ~~~~~~~~~~ ^ include/asm-generic/io.h:643:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] writesw(PCI_IOBASE + addr, buffer, count); ~~~~~~~~~~ ^ include/asm-generic/io.h:652:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] writesl(PCI_IOBASE + addr, buffer, count); ~~~~~~~~~~ ^ cmd->tvc_se_cmd.map_cpu = cpu; ^~~ drivers/vhost/scsi.c:583:14: note: initialize the variable 'cpu' to silence this warning int tag, cpu; ^ = 0 21 warnings generated. # https://github.com/0day-ci/linux/commit/aef0e1e9298ab68f2d7bdf1afb9a37664... git remote add linux-review https://github.com/0day-ci/linux git fetch --no-tags linux-review Mike-Christie/vhost-scsi-fixes-and-cleanups/20200922-031251 git checkout aef0e1e9298ab68f2d7bdf1afb9a376641b993d5 vim +/cpu +606 drivers/vhost/scsi.c 057cbf49a1f082 drivers/vhost/tcm_vhost.c Nicholas Bellinger 2012-07-18 571 1a1ff8256af679 drivers/vhost/scsi.c Nicholas Bellinger 2015-01-31 572 static struct vhost_scsi_cmd * aef0e1e9298ab6 drivers/vhost/scsi.c Mike Christie 2020-09-21 573 vhost_scsi_get_cmd(struct vhost_virtqueue *vq, struct vhost_scsi_tpg *tpg, 95e7c4341b8e28 drivers/vhost/scsi.c Nicholas Bellinger 2014-02-22 574 unsigned char *cdb, u64 scsi_tag, u16 lun, u8 task_attr, 95e7c4341b8e28 drivers/vhost/scsi.c Nicholas Bellinger 2014-02-22 575 u32 exp_data_len, int data_direction) 057cbf49a1f082 drivers/vhost/tcm_vhost.c Nicholas Bellinger 2012-07-18 576 { aef0e1e9298ab6 drivers/vhost/scsi.c Mike Christie 2020-09-21 577 struct vhost_scsi_virtqueue *svq = container_of(vq, aef0e1e9298ab6 drivers/vhost/scsi.c Mike Christie 2020-09-21 578 struct vhost_scsi_virtqueue, vq); 1a1ff8256af679 drivers/vhost/scsi.c Nicholas Bellinger 2015-01-31 579 struct vhost_scsi_cmd *cmd; 1a1ff8256af679 drivers/vhost/scsi.c Nicholas Bellinger 2015-01-31 580 struct vhost_scsi_nexus *tv_nexus; b1935f687bb93b drivers/vhost/scsi.c Nicholas Bellinger 2014-02-22 581 struct scatterlist *sg, *prot_sg; 3aee26b4ae9104 drivers/vhost/scsi.c Nicholas Bellinger 2013-06-21 582 struct page **pages; 10e9cbb6b53111 drivers/vhost/scsi.c Matthew Wilcox 2018-06-12 583 int tag, cpu; 057cbf49a1f082 drivers/vhost/tcm_vhost.c Nicholas Bellinger 2012-07-18 584 9871831283e795 drivers/vhost/scsi.c Asias He 2013-05-06 585 tv_nexus = tpg->tpg_nexus; 057cbf49a1f082 drivers/vhost/tcm_vhost.c Nicholas Bellinger 2012-07-18 586 if (!tv_nexus) { 1a1ff8256af679 drivers/vhost/scsi.c Nicholas Bellinger 2015-01-31 587 pr_err("Unable to locate active struct vhost_scsi_nexus\n"); 057cbf49a1f082 drivers/vhost/tcm_vhost.c Nicholas Bellinger 2012-07-18 588 return ERR_PTR(-EIO); 057cbf49a1f082 drivers/vhost/tcm_vhost.c Nicholas Bellinger 2012-07-18 589 } 057cbf49a1f082 drivers/vhost/tcm_vhost.c Nicholas Bellinger 2012-07-18 590 aef0e1e9298ab6 drivers/vhost/scsi.c Mike Christie 2020-09-21 591 tag = sbitmap_get(&svq->scsi_tags, 0, false); 4a47d3a1ff10e5 drivers/vhost/scsi.c Nicholas Bellinger 2013-09-23 592 if (tag < 0) { 1a1ff8256af679 drivers/vhost/scsi.c Nicholas Bellinger 2015-01-31 593 pr_err("Unable to obtain tag for vhost_scsi_cmd\n"); 4a47d3a1ff10e5 drivers/vhost/scsi.c Nicholas Bellinger 2013-09-23 594 return ERR_PTR(-ENOMEM); 4a47d3a1ff10e5 drivers/vhost/scsi.c Nicholas Bellinger 2013-09-23 595 } 4a47d3a1ff10e5 drivers/vhost/scsi.c Nicholas Bellinger 2013-09-23 596 aef0e1e9298ab6 drivers/vhost/scsi.c Mike Christie 2020-09-21 597 cmd = &svq->scsi_cmds[tag]; 3aee26b4ae9104 drivers/vhost/scsi.c Nicholas Bellinger 2013-06-21 598 sg = cmd->tvc_sgl; b1935f687bb93b drivers/vhost/scsi.c Nicholas Bellinger 2014-02-22 599 prot_sg = cmd->tvc_prot_sgl; 3aee26b4ae9104 drivers/vhost/scsi.c Nicholas Bellinger 2013-06-21 600 pages = cmd->tvc_upages; 473f0b15a4c97d drivers/vhost/scsi.c Markus Elfring 2017-05-20 601 memset(cmd, 0, sizeof(*cmd)); 3aee26b4ae9104 drivers/vhost/scsi.c Nicholas Bellinger 2013-06-21 602 cmd->tvc_sgl = sg; b1935f687bb93b drivers/vhost/scsi.c Nicholas Bellinger 2014-02-22 603 cmd->tvc_prot_sgl = prot_sg; 3aee26b4ae9104 drivers/vhost/scsi.c Nicholas Bellinger 2013-06-21 604 cmd->tvc_upages = pages; 4824d3bfb9097a drivers/vhost/scsi.c Nicholas Bellinger 2013-06-07 605 cmd->tvc_se_cmd.map_tag = tag; 10e9cbb6b53111 drivers/vhost/scsi.c Matthew Wilcox 2018-06-12 @606 cmd->tvc_se_cmd.map_cpu = cpu; 95e7c4341b8e28 drivers/vhost/scsi.c Nicholas Bellinger 2014-02-22 607 cmd->tvc_tag = scsi_tag; 95e7c4341b8e28 drivers/vhost/scsi.c Nicholas Bellinger 2014-02-22 608 cmd->tvc_lun = lun; 95e7c4341b8e28 drivers/vhost/scsi.c Nicholas Bellinger 2014-02-22 609 cmd->tvc_task_attr = task_attr; 3c63f66a0dcdd6 drivers/vhost/scsi.c Asias He 2013-05-06 610 cmd->tvc_exp_data_len = exp_data_len; 3c63f66a0dcdd6 drivers/vhost/scsi.c Asias He 2013-05-06 611 cmd->tvc_data_direction = data_direction; 3c63f66a0dcdd6 drivers/vhost/scsi.c Asias He 2013-05-06 612 cmd->tvc_nexus = tv_nexus; 1a1ff8256af679 drivers/vhost/scsi.c Nicholas Bellinger 2015-01-31 613 cmd->inflight = vhost_scsi_get_inflight(vq); 057cbf49a1f082 drivers/vhost/tcm_vhost.c Nicholas Bellinger 2012-07-18 614 1a1ff8256af679 drivers/vhost/scsi.c Nicholas Bellinger 2015-01-31 615 memcpy(cmd->tvc_cdb, cdb, VHOST_SCSI_MAX_CDB_SIZE); 95e7c4341b8e28 drivers/vhost/scsi.c Nicholas Bellinger 2014-02-22 616 3c63f66a0dcdd6 drivers/vhost/scsi.c Asias He 2013-05-06 617 return cmd; 057cbf49a1f082 drivers/vhost/tcm_vhost.c Nicholas Bellinger 2012-07-18 618 } 057cbf49a1f082 drivers/vhost/tcm_vhost.c Nicholas Bellinger 2012-07-18 619 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org