drivers/rapidio/rio_cm.c:240:21: warning: variable 'dev_minor_base' set but not used
From: kernel test robot
Date: Sun Mar 29 2026 - 21:29:40 EST
Hi Tiwei,
First bad commit (maybe != root cause):
tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head: 7aaa8047eafd0bd628065b15757d9b48c5f9c07d
commit: a0e2cb6a90634f3dc80f16e882a683ee5761b0b0 um: Add VFIO-based virtual PCI driver
date: 11 months ago
config: um-randconfig-002-20260330 (https://download.01.org/0day-ci/archive/20260330/202603300941.gWpJLYkn-lkp@xxxxxxxxx/config)
compiler: clang version 23.0.0git (https://github.com/llvm/llvm-project 054e11d1a17e5ba88bb1a8ef32fad3346e80b186)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260330/202603300941.gWpJLYkn-lkp@xxxxxxxxx/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@xxxxxxxxx>
| Closes: https://lore.kernel.org/oe-kbuild-all/202603300941.gWpJLYkn-lkp@xxxxxxxxx/
All warnings (new ones prefixed by >>):
In file included from drivers/rapidio/rio_cm.c:12:
In file included from include/linux/dma-mapping.h:8:
In file included from include/linux/scatterlist.h:9:
In file included from arch/um/include/asm/io.h:24:
include/asm-generic/io.h:549:31: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
549 | val = __raw_readb(PCI_IOBASE + addr);
| ~~~~~~~~~~ ^
include/asm-generic/io.h:567:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
567 | val = __le16_to_cpu((__le16 __force)__raw_readw(PCI_IOBASE + addr));
| ~~~~~~~~~~ ^
include/uapi/linux/byteorder/little_endian.h:37:51: note: expanded from macro '__le16_to_cpu'
37 | #define __le16_to_cpu(x) ((__force __u16)(__le16)(x))
| ^
In file included from drivers/rapidio/rio_cm.c:12:
In file included from include/linux/dma-mapping.h:8:
In file included from include/linux/scatterlist.h:9:
In file included from arch/um/include/asm/io.h:24:
include/asm-generic/io.h:585:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
585 | val = __le32_to_cpu((__le32 __force)__raw_readl(PCI_IOBASE + addr));
| ~~~~~~~~~~ ^
include/uapi/linux/byteorder/little_endian.h:35:51: note: expanded from macro '__le32_to_cpu'
35 | #define __le32_to_cpu(x) ((__force __u32)(__le32)(x))
| ^
In file included from drivers/rapidio/rio_cm.c:12:
In file included from include/linux/dma-mapping.h:8:
In file included from include/linux/scatterlist.h:9:
In file included from arch/um/include/asm/io.h:24:
include/asm-generic/io.h:601:33: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
601 | __raw_writeb(value, PCI_IOBASE + addr);
| ~~~~~~~~~~ ^
include/asm-generic/io.h:616:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
616 | __raw_writew((u16 __force)cpu_to_le16(value), PCI_IOBASE + addr);
| ~~~~~~~~~~ ^
include/asm-generic/io.h:631:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
631 | __raw_writel((u32 __force)cpu_to_le32(value), PCI_IOBASE + addr);
| ~~~~~~~~~~ ^
include/asm-generic/io.h:724:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
724 | readsb(PCI_IOBASE + addr, buffer, count);
| ~~~~~~~~~~ ^
include/asm-generic/io.h:737:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
737 | readsw(PCI_IOBASE + addr, buffer, count);
| ~~~~~~~~~~ ^
include/asm-generic/io.h:750:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
750 | readsl(PCI_IOBASE + addr, buffer, count);
| ~~~~~~~~~~ ^
include/asm-generic/io.h:764:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
764 | writesb(PCI_IOBASE + addr, buffer, count);
| ~~~~~~~~~~ ^
include/asm-generic/io.h:778:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
778 | writesw(PCI_IOBASE + addr, buffer, count);
| ~~~~~~~~~~ ^
include/asm-generic/io.h:792:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
792 | writesl(PCI_IOBASE + addr, buffer, count);
| ~~~~~~~~~~ ^
drivers/rapidio/rio_cm.c:675:7: warning: variable 'rc' set but not used [-Wunused-but-set-variable]
675 | int rc;
| ^
>> drivers/rapidio/rio_cm.c:240:21: warning: variable 'dev_minor_base' set but not used [-Wunused-but-set-global]
240 | static unsigned int dev_minor_base;
| ^
14 warnings generated.
vim +/dev_minor_base +240 drivers/rapidio/rio_cm.c
b6e8d4aa111030 Alexandre Bounine 2016-08-02 235
d712d205210c49 Ivan Orlov 2023-08-10 236 static const struct class dev_class = {
d712d205210c49 Ivan Orlov 2023-08-10 237 .name = DRV_NAME,
d712d205210c49 Ivan Orlov 2023-08-10 238 };
b6e8d4aa111030 Alexandre Bounine 2016-08-02 239 static unsigned int dev_major;
b6e8d4aa111030 Alexandre Bounine 2016-08-02 @240 static unsigned int dev_minor_base;
b6e8d4aa111030 Alexandre Bounine 2016-08-02 241 static dev_t dev_number;
b6e8d4aa111030 Alexandre Bounine 2016-08-02 242 static struct channel_dev riocm_cdev;
b6e8d4aa111030 Alexandre Bounine 2016-08-02 243
:::::: The code at line 240 was first introduced by commit
:::::: b6e8d4aa1110306378af0f3472a6b85a1f039a16 rapidio: add RapidIO channelized messaging driver
:::::: TO: Alexandre Bounine <alexandre.bounine@xxxxxxx>
:::::: CC: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
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