linux-kernel - arch/riscv/include/asm/io.h:108:53: warning: performing pointer arithmetic on a null pointer has undefined behavior

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [day] [month] [year] [list]
Message-ID: <202512300518.85jsnXn2-lkp@intel.com>
Date: Tue, 30 Dec 2025 05:24:19 +0800
From: kernel test robot <lkp@...el.com>
To: Danilo Krummrich <dakr@...nel.org>
Cc: oe-kbuild-all@...ts.linux.dev, linux-kernel@...r.kernel.org,
 Alice Ryhl <aliceryhl@...gle.com>,
 Joel Fernandes <joelagnelf@...dia.com>
Subject: arch/riscv/include/asm/io.h:108:53: warning: performing
 pointer arithmetic on a null pointer has undefined behavior

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head:   8640b74557fc8b4c300030f6ccb8cd078f665ec8
commit: 473b9f331718267815649cd93801da832200db71 rust: pci: fix build failure when CONFIG_PCI_MSI is disabled
date:   4 weeks ago
config: riscv-randconfig-r063-20251230 (https://download.01.org/0day-ci/archive/20251230/202512300518.85jsnXn2-lkp@intel.com/config)
compiler: clang version 22.0.0git (https://github.com/llvm/llvm-project 4ef602d446057dabf5f61fb221669ecbeda49279)
rustc: rustc 1.88.0 (6b00bc388 2025-06-23)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20251230/202512300518.85jsnXn2-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@...el.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202512300518.85jsnXn2-lkp@intel.com/

All warnings (new ones prefixed by >>):

   In file included from include/linux/blk-mq.h:5:
   In file included from include/linux/blkdev.h:9:
   In file included from include/linux/blk_types.h:10:
   In file included from include/linux/bvec.h:10:
   In file included from include/linux/highmem.h:12:
   In file included from include/linux/hardirq.h:11:
   In file included from ./arch/riscv/include/generated/asm/hardirq.h:1:
   In file included from include/asm-generic/hardirq.h:17:
   In file included from include/linux/irq.h:20:
   In file included from include/linux/io.h:12:
   In file included from arch/riscv/include/asm/io.h:140:
   include/asm-generic/io.h:854:2: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
   854 |         insl(addr, buffer, count);
   |         ^~~~~~~~~~~~~~~~~~~~~~~~~
   arch/riscv/include/asm/io.h:110:53: note: expanded from macro 'insl'
   110 | #define insl(addr, buffer, count) __insl(PCI_IOBASE + (addr), buffer, count)
   |                                          ~~~~~~~~~~ ^
   In file included from rust/helpers/helpers.c:16:
   In file included from rust/helpers/blk.c:3:
   In file included from include/linux/blk-mq.h:5:
   In file included from include/linux/blkdev.h:9:
   In file included from include/linux/blk_types.h:10:
   In file included from include/linux/bvec.h:10:
   In file included from include/linux/highmem.h:12:
   In file included from include/linux/hardirq.h:11:
   In file included from ./arch/riscv/include/generated/asm/hardirq.h:1:
   In file included from include/asm-generic/hardirq.h:17:
   In file included from include/linux/irq.h:20:
   In file included from include/linux/io.h:12:
   In file included from arch/riscv/include/asm/io.h:140:
   include/asm-generic/io.h:863:2: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
   863 |         outsb(addr, buffer, count);
   |         ^~~~~~~~~~~~~~~~~~~~~~~~~~
   arch/riscv/include/asm/io.h:122:55: note: expanded from macro 'outsb'
   122 | #define outsb(addr, buffer, count) __outsb(PCI_IOBASE + (addr), buffer, count)
   |                                            ~~~~~~~~~~ ^
   In file included from rust/helpers/helpers.c:16:
   In file included from rust/helpers/blk.c:3:
   In file included from include/linux/blk-mq.h:5:
   In file included from include/linux/blkdev.h:9:
   In file included from include/linux/blk_types.h:10:
   In file included from include/linux/bvec.h:10:
   In file included from include/linux/highmem.h:12:
   In file included from include/linux/hardirq.h:11:
   In file included from ./arch/riscv/include/generated/asm/hardirq.h:1:
   In file included from include/asm-generic/hardirq.h:17:
   In file included from include/linux/irq.h:20:
   In file included from include/linux/io.h:12:
   In file included from arch/riscv/include/asm/io.h:140:
   include/asm-generic/io.h:872:2: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
   872 |         outsw(addr, buffer, count);
   |         ^~~~~~~~~~~~~~~~~~~~~~~~~~
   arch/riscv/include/asm/io.h:123:55: note: expanded from macro 'outsw'
   123 | #define outsw(addr, buffer, count) __outsw(PCI_IOBASE + (addr), buffer, count)
   |                                            ~~~~~~~~~~ ^
   In file included from rust/helpers/helpers.c:16:
   In file included from rust/helpers/blk.c:3:
   In file included from include/linux/blk-mq.h:5:
   In file included from include/linux/blkdev.h:9:
   In file included from include/linux/blk_types.h:10:
   In file included from include/linux/bvec.h:10:
   In file included from include/linux/highmem.h:12:
   In file included from include/linux/hardirq.h:11:
   In file included from ./arch/riscv/include/generated/asm/hardirq.h:1:
   In file included from include/asm-generic/hardirq.h:17:
   In file included from include/linux/irq.h:20:
   In file included from include/linux/io.h:12:
   In file included from arch/riscv/include/asm/io.h:140:
   include/asm-generic/io.h:881:2: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
   881 |         outsl(addr, buffer, count);
   |         ^~~~~~~~~~~~~~~~~~~~~~~~~~
   arch/riscv/include/asm/io.h:124:55: note: expanded from macro 'outsl'
   124 | #define outsl(addr, buffer, count) __outsl(PCI_IOBASE + (addr), buffer, count)
   |                                            ~~~~~~~~~~ ^
   In file included from rust/helpers/helpers.c:16:
   In file included from rust/helpers/blk.c:3:
   In file included from include/linux/blk-mq.h:5:
   In file included from include/linux/blkdev.h:9:
   In file included from include/linux/blk_types.h:10:
   In file included from include/linux/bvec.h:10:
   In file included from include/linux/highmem.h:12:
   In file included from include/linux/hardirq.h:11:
   In file included from ./arch/riscv/include/generated/asm/hardirq.h:1:
   In file included from include/asm-generic/hardirq.h:17:
   In file included from include/linux/irq.h:20:
   In file included from include/linux/io.h:12:
   In file included from arch/riscv/include/asm/io.h:140:
   include/asm-generic/io.h:1209:55: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
   1209 |         return (port > MMIO_UPPER_LIMIT) ? NULL : PCI_IOBASE + port;
   |                                                   ~~~~~~~~~~ ^
   In file included from rust/helpers/helpers.c:40:
   rust/helpers/pci.c:36:2: error: call to undeclared function 'pci_free_irq_vectors'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
   36 |         pci_free_irq_vectors(dev);
   |         ^
   rust/helpers/pci.c:36:2: note: did you mean 'pci_alloc_irq_vectors'?
   include/linux/pci.h:2161:1: note: 'pci_alloc_irq_vectors' declared here
   2161 | pci_alloc_irq_vectors(struct pci_dev *dev, unsigned int min_vecs,
   | ^
   7 warnings and 1 error generated.
   make[3]: *** [rust/Makefile:495: rust/helpers/helpers.o] Error 1
>> arch/riscv/include/asm/io.h:108:53: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
   arch/riscv/include/asm/io.h:109:53: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
   arch/riscv/include/asm/io.h:110:53: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
   arch/riscv/include/asm/io.h:122:55: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
   arch/riscv/include/asm/io.h:123:55: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
   arch/riscv/include/asm/io.h:124:55: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
   include/asm-generic/io.h:1209:55: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
   rust/helpers/pci.c:36:2: error: call to undeclared function 'pci_free_irq_vectors'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
>> clang diag: arch/riscv/include/asm/io.h:108:53: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
   clang diag: arch/riscv/include/asm/io.h:109:53: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
   clang diag: arch/riscv/include/asm/io.h:110:53: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
   clang diag: arch/riscv/include/asm/io.h:122:55: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
   clang diag: arch/riscv/include/asm/io.h:123:55: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
   clang diag: arch/riscv/include/asm/io.h:124:55: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
   clang diag: include/asm-generic/io.h:1209:55: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
   Unable to generate bindings: clang diagnosed error: rust/helpers/pci.c:36:2: error: call to undeclared function 'pci_free_irq_vectors'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
--
   make[3]: *** [rust/Makefile:384: rust/bindings/bindings_helpers_generated.rs] Error 1
   make[3]: *** Deleting file 'rust/bindings/bindings_helpers_generated.rs'
>> clang diag: arch/riscv/include/asm/io.h:108:53: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
   clang diag: arch/riscv/include/asm/io.h:109:53: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
   clang diag: arch/riscv/include/asm/io.h:110:53: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
   clang diag: arch/riscv/include/asm/io.h:122:55: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
   clang diag: arch/riscv/include/asm/io.h:123:55: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
   clang diag: arch/riscv/include/asm/io.h:124:55: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
   clang diag: include/asm-generic/io.h:1209:55: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>> clang diag: arch/riscv/include/asm/io.h:108:53: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
   clang diag: arch/riscv/include/asm/io.h:109:53: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
   clang diag: arch/riscv/include/asm/io.h:110:53: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
   clang diag: arch/riscv/include/asm/io.h:122:55: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
   clang diag: arch/riscv/include/asm/io.h:123:55: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
   clang diag: arch/riscv/include/asm/io.h:124:55: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
   clang diag: include/asm-generic/io.h:1209:55: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
   make[3]: Target 'rust/' not remade because of errors.
   make[2]: *** [Makefile:1286: prepare] Error 2
   make[1]: *** [Makefile:248: __sub-make] Error 2
   make[1]: Target 'prepare' not remade because of errors.
   make: *** [Makefile:248: __sub-make] Error 2
   make: Target 'prepare' not remade because of errors.


vim +108 arch/riscv/include/asm/io.h

fab957c11efe2f Palmer Dabbelt    2017-07-10  104  
ce246c444a08e0 Will Deacon       2019-02-22  105  __io_reads_ins(ins,  u8, b, __io_pbr(), __io_par(addr))
ce246c444a08e0 Will Deacon       2019-02-22  106  __io_reads_ins(ins, u16, w, __io_pbr(), __io_par(addr))
ce246c444a08e0 Will Deacon       2019-02-22  107  __io_reads_ins(ins, u32, l, __io_pbr(), __io_par(addr))
9cc205e3c17d57 Maciej W. Rozycki 2022-09-22 @108  #define insb(addr, buffer, count) __insb(PCI_IOBASE + (addr), buffer, count)
9cc205e3c17d57 Maciej W. Rozycki 2022-09-22  109  #define insw(addr, buffer, count) __insw(PCI_IOBASE + (addr), buffer, count)
9cc205e3c17d57 Maciej W. Rozycki 2022-09-22  110  #define insl(addr, buffer, count) __insl(PCI_IOBASE + (addr), buffer, count)
fab957c11efe2f Palmer Dabbelt    2017-07-10  111  

:::::: The code at line 108 was first introduced by commit
:::::: 9cc205e3c17d5716da7ebb7fa0c985555e95d009 RISC-V: Make port I/O string accessors actually work

:::::: TO: Maciej W. Rozycki <macro@...am.me.uk>
:::::: CC: Palmer Dabbelt <palmer@...osinc.com>

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki