[kbuild-all] drivers/infiniband/hw/qib/qib_sysfs.c:411:1: warning: performing pointer subtraction with a null pointer has undefined behavior

tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master head: 8cae8cd89f05f6de223d63e6d15e31c8ba9cf53b commit: 4a7aaf88c89f12f8048137e274ce0d40fe1056b2 RDMA/qib: Use attributes for the port sysfs date: 5 weeks ago config: x86_64-randconfig-r016-20210720 (attached as .config) compiler: clang version 13.0.0 (https://github.com/llvm/llvm-project c781eb153bfbd1b52b03efe34f56bbeccbb8aba6) 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 x86_64 cross compiling tool for clang build # apt-get install binutils-x86-64-linux-gnu # https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit... git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git git fetch --no-tags linus master git checkout 4a7aaf88c89f12f8048137e274ce0d40fe1056b2 # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=x86_64 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 >>): QIB_DIAGC_ATTR(rc_resends); ^~~~~~~~~~~~~~~~~~~~~~~~~~ drivers/infiniband/hw/qib/qib_sysfs.c:408:51: note: expanded from macro 'QIB_DIAGC_ATTR' .counter = &((struct qib_ibport *)0)->rvp.n_##N - (u64 *)0, \ ^ ~~~~~~~~ drivers/infiniband/hw/qib/qib_sysfs.c:412:1: warning: performing pointer subtraction with a null pointer has undefined behavior [-Wnull-pointer-subtraction] QIB_DIAGC_ATTR(seq_naks); ^~~~~~~~~~~~~~~~~~~~~~~~ drivers/infiniband/hw/qib/qib_sysfs.c:408:51: note: expanded from macro 'QIB_DIAGC_ATTR' .counter = &((struct qib_ibport *)0)->rvp.n_##N - (u64 *)0, \ ^ ~~~~~~~~ drivers/infiniband/hw/qib/qib_sysfs.c:413:1: warning: performing pointer subtraction with a null pointer has undefined behavior [-Wnull-pointer-subtraction] QIB_DIAGC_ATTR(rdma_seq); ^~~~~~~~~~~~~~~~~~~~~~~~ drivers/infiniband/hw/qib/qib_sysfs.c:408:51: note: expanded from macro 'QIB_DIAGC_ATTR' .counter = &((struct qib_ibport *)0)->rvp.n_##N - (u64 *)0, \ ^ ~~~~~~~~ drivers/infiniband/hw/qib/qib_sysfs.c:414:1: warning: performing pointer subtraction with a null pointer has undefined behavior [-Wnull-pointer-subtraction] QIB_DIAGC_ATTR(rnr_naks); ^~~~~~~~~~~~~~~~~~~~~~~~ drivers/infiniband/hw/qib/qib_sysfs.c:408:51: note: expanded from macro 'QIB_DIAGC_ATTR' .counter = &((struct qib_ibport *)0)->rvp.n_##N - (u64 *)0, \ ^ ~~~~~~~~ drivers/infiniband/hw/qib/qib_sysfs.c:415:1: warning: performing pointer subtraction with a null pointer has undefined behavior [-Wnull-pointer-subtraction] QIB_DIAGC_ATTR(other_naks); ^~~~~~~~~~~~~~~~~~~~~~~~~~ drivers/infiniband/hw/qib/qib_sysfs.c:408:51: note: expanded from macro 'QIB_DIAGC_ATTR' .counter = &((struct qib_ibport *)0)->rvp.n_##N - (u64 *)0, \ ^ ~~~~~~~~ drivers/infiniband/hw/qib/qib_sysfs.c:416:1: warning: performing pointer subtraction with a null pointer has undefined behavior [-Wnull-pointer-subtraction] QIB_DIAGC_ATTR(rc_timeouts); ^~~~~~~~~~~~~~~~~~~~~~~~~~~ drivers/infiniband/hw/qib/qib_sysfs.c:408:51: note: expanded from macro 'QIB_DIAGC_ATTR' .counter = &((struct qib_ibport *)0)->rvp.n_##N - (u64 *)0, \ ^ ~~~~~~~~ drivers/infiniband/hw/qib/qib_sysfs.c:417:1: warning: performing pointer subtraction with a null pointer has undefined behavior [-Wnull-pointer-subtraction] QIB_DIAGC_ATTR(loop_pkts); ^~~~~~~~~~~~~~~~~~~~~~~~~ drivers/infiniband/hw/qib/qib_sysfs.c:408:51: note: expanded from macro 'QIB_DIAGC_ATTR' .counter = &((struct qib_ibport *)0)->rvp.n_##N - (u64 *)0, \ ^ ~~~~~~~~ drivers/infiniband/hw/qib/qib_sysfs.c:418:1: warning: performing pointer subtraction with a null pointer has undefined behavior [-Wnull-pointer-subtraction] QIB_DIAGC_ATTR(pkt_drops); ^~~~~~~~~~~~~~~~~~~~~~~~~ drivers/infiniband/hw/qib/qib_sysfs.c:408:51: note: expanded from macro 'QIB_DIAGC_ATTR' .counter = &((struct qib_ibport *)0)->rvp.n_##N - (u64 *)0, \ ^ ~~~~~~~~ drivers/infiniband/hw/qib/qib_sysfs.c:419:1: warning: performing pointer subtraction with a null pointer has undefined behavior [-Wnull-pointer-subtraction] QIB_DIAGC_ATTR(dmawait); ^~~~~~~~~~~~~~~~~~~~~~~ drivers/infiniband/hw/qib/qib_sysfs.c:408:51: note: expanded from macro 'QIB_DIAGC_ATTR' .counter = &((struct qib_ibport *)0)->rvp.n_##N - (u64 *)0, \ ^ ~~~~~~~~ drivers/infiniband/hw/qib/qib_sysfs.c:420:1: warning: performing pointer subtraction with a null pointer has undefined behavior [-Wnull-pointer-subtraction] QIB_DIAGC_ATTR(unaligned); ^~~~~~~~~~~~~~~~~~~~~~~~~ drivers/infiniband/hw/qib/qib_sysfs.c:408:51: note: expanded from macro 'QIB_DIAGC_ATTR' .counter = &((struct qib_ibport *)0)->rvp.n_##N - (u64 *)0, \ ^ ~~~~~~~~ drivers/infiniband/hw/qib/qib_sysfs.c:421:1: warning: performing pointer subtraction with a null pointer has undefined behavior [-Wnull-pointer-subtraction] QIB_DIAGC_ATTR(rc_dupreq); ^~~~~~~~~~~~~~~~~~~~~~~~~ drivers/infiniband/hw/qib/qib_sysfs.c:408:51: note: expanded from macro 'QIB_DIAGC_ATTR' .counter = &((struct qib_ibport *)0)->rvp.n_##N - (u64 *)0, \ ^ ~~~~~~~~ drivers/infiniband/hw/qib/qib_sysfs.c:422:1: warning: performing pointer subtraction with a null pointer has undefined behavior [-Wnull-pointer-subtraction] QIB_DIAGC_ATTR(rc_seqnak); ^~~~~~~~~~~~~~~~~~~~~~~~~ drivers/infiniband/hw/qib/qib_sysfs.c:408:51: note: expanded from macro 'QIB_DIAGC_ATTR' .counter = &((struct qib_ibport *)0)->rvp.n_##N - (u64 *)0, \ ^ ~~~~~~~~ drivers/infiniband/hw/qib/qib_sysfs.c:423:1: warning: performing pointer subtraction with a null pointer has undefined behavior [-Wnull-pointer-subtraction] QIB_DIAGC_ATTR(rc_crwaits); ^~~~~~~~~~~~~~~~~~~~~~~~~~ drivers/infiniband/hw/qib/qib_sysfs.c:408:51: note: expanded from macro 'QIB_DIAGC_ATTR' .counter = &((struct qib_ibport *)0)->rvp.n_##N - (u64 *)0, \ ^ ~~~~~~~~ 13 warnings generated. vim +411 drivers/infiniband/hw/qib/qib_sysfs.c f24a6d4887668c Harish Chegondi 2016-01-22 404 4a7aaf88c89f12 Jason Gunthorpe 2021-06-11 405 #define QIB_DIAGC_ATTR(N) \ f24a6d4887668c Harish Chegondi 2016-01-22 406 static struct qib_diagc_attr qib_diagc_attr_##N = { \ 4a7aaf88c89f12 Jason Gunthorpe 2021-06-11 407 .attr = __ATTR(N, 0664, diagc_attr_show, diagc_attr_store), \ 4a7aaf88c89f12 Jason Gunthorpe 2021-06-11 408 .counter = &((struct qib_ibport *)0)->rvp.n_##N - (u64 *)0, \ f931551bafe1f1 Ralph Campbell 2010-05-23 409 } f931551bafe1f1 Ralph Campbell 2010-05-23 410 f931551bafe1f1 Ralph Campbell 2010-05-23 @411 QIB_DIAGC_ATTR(rc_resends); f931551bafe1f1 Ralph Campbell 2010-05-23 412 QIB_DIAGC_ATTR(seq_naks); f931551bafe1f1 Ralph Campbell 2010-05-23 413 QIB_DIAGC_ATTR(rdma_seq); f931551bafe1f1 Ralph Campbell 2010-05-23 414 QIB_DIAGC_ATTR(rnr_naks); f931551bafe1f1 Ralph Campbell 2010-05-23 415 QIB_DIAGC_ATTR(other_naks); f931551bafe1f1 Ralph Campbell 2010-05-23 416 QIB_DIAGC_ATTR(rc_timeouts); f931551bafe1f1 Ralph Campbell 2010-05-23 417 QIB_DIAGC_ATTR(loop_pkts); f931551bafe1f1 Ralph Campbell 2010-05-23 418 QIB_DIAGC_ATTR(pkt_drops); f931551bafe1f1 Ralph Campbell 2010-05-23 419 QIB_DIAGC_ATTR(dmawait); f931551bafe1f1 Ralph Campbell 2010-05-23 420 QIB_DIAGC_ATTR(unaligned); f931551bafe1f1 Ralph Campbell 2010-05-23 421 QIB_DIAGC_ATTR(rc_dupreq); f931551bafe1f1 Ralph Campbell 2010-05-23 422 QIB_DIAGC_ATTR(rc_seqnak); 7199435414868b Kaike Wan 2019-09-11 423 QIB_DIAGC_ATTR(rc_crwaits); f931551bafe1f1 Ralph Campbell 2010-05-23 424 :::::: The code at line 411 was first introduced by commit :::::: f931551bafe1f10ded7f5282e2aa162c267a2e5d IB/qib: Add new qib driver for QLogic PCIe InfiniBand adapters :::::: TO: Ralph Campbell <ralph.campbell(a)qlogic.com&gt; :::::: CC: Roland Dreier <rolandd(a)cisco.com&gt; 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