[openeuler:openEuler-1.0-LTS 1341/1341] include/linux/uaccess.h:112:17: warning: 'bind' may be used uninitialized - Kernel

21 Dec 2024


      Hi Jean-Philippe,
FYI, the error/warning still remains.
tree:   https://gitee.com/openeuler/kernel.git openEuler-1.0-LTS
head:   02951ceaa6d546dfa0f741f52f6d47e0fb0ac7b4
commit: 2dd8345826607c5d2d6528de872118da554015b6 [1341/1341] vfio: Add support for Shared Virtual Addressing
config: arm64-randconfig-002-20241220 (https://download.01.org/0day-ci/archive/20241221/202412210041.OxTX5o7L-lkp@i...)
compiler: aarch64-linux-gcc (GCC) 14.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20241221/202412210041.OxTX5o7L-lkp@i...)
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@intel.com
| Closes: https://lore.kernel.org/oe-kbuild-all/202412210041.OxTX5o7L-lkp@intel.com/
Note: it may well be a FALSE warning. FWIW you are at least aware of it now.
http://gcc.gnu.org/wiki/Better_Uninitialized_Warnings
All warnings (new ones prefixed by >>):
In file included from include/linux/compat.h:19,
                    from drivers/vfio/vfio_iommu_type1.c:27:
   In function '_copy_from_user',
       inlined from 'copy_from_user' at include/linux/uaccess.h:144:7,
       inlined from 'vfio_iommu_type1_bind_process' at drivers/vfio/vfio_iommu_type1.c:1933:6:
   include/linux/uaccess.h:112:17: warning: 'params' may be used uninitialized [-Wmaybe-uninitialized]
     112 |                 kasan_check_write(to, n);
         |                 ^~~~~~~~~~~~~~~~~~~~~~~~
   In file included from include/linux/compiler.h:251,
                    from include/asm-generic/div64.h:25,
                    from ./arch/arm64/include/generated/asm/div64.h:1,
                    from include/linux/math64.h:6,
                    from include/linux/time64.h:5,
                    from include/linux/compat_time.h:6,
                    from include/linux/compat.h:10:
   include/linux/kasan-checks.h: In function 'vfio_iommu_type1_bind_process':
   include/linux/kasan-checks.h:7:6: note: by argument 1 of type 'const volatile void *' to 'kasan_check_write' declared here
       7 | void kasan_check_write(const volatile void *p, unsigned int size);
         |      ^~~~~~~~~~~~~~~~~
   drivers/vfio/vfio_iommu_type1.c:1920:46: note: 'params' declared here
    1920 |         struct vfio_iommu_type1_bind_process params;
         |                                              ^~~~~~
   In function '_copy_from_user',
       inlined from 'copy_from_user' at include/linux/uaccess.h:144:7,
       inlined from 'vfio_iommu_type1_unbind_process' at drivers/vfio/vfio_iommu_type1.c:2021:6:
   include/linux/uaccess.h:112:17: warning: 'params' may be used uninitialized [-Wmaybe-uninitialized]
     112 |                 kasan_check_write(to, n);
         |                 ^~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/kasan-checks.h: In function 'vfio_iommu_type1_unbind_process':
   include/linux/kasan-checks.h:7:6: note: by argument 1 of type 'const volatile void *' to 'kasan_check_write' declared here
       7 | void kasan_check_write(const volatile void *p, unsigned int size);
         |      ^~~~~~~~~~~~~~~~~
   drivers/vfio/vfio_iommu_type1.c:2014:46: note: 'params' declared here
    2014 |         struct vfio_iommu_type1_bind_process params;
         |                                              ^~~~~~
   In function '_copy_from_user',
       inlined from 'copy_from_user' at include/linux/uaccess.h:144:7,
       inlined from 'vfio_iommu_type1_ioctl.part.0' at drivers/vfio/vfio_iommu_type1.c:2084:7:
   include/linux/uaccess.h:112:17: warning: 'info' may be used uninitialized [-Wmaybe-uninitialized]
     112 |                 kasan_check_write(to, n);
         |                 ^~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/kasan-checks.h: In function 'vfio_iommu_type1_ioctl.part.0':
   include/linux/kasan-checks.h:7:6: note: by argument 1 of type 'const volatile void *' to 'kasan_check_write' declared here
       7 | void kasan_check_write(const volatile void *p, unsigned int size);
         |      ^~~~~~~~~~~~~~~~~
   drivers/vfio/vfio_iommu_type1.c:2080:46: note: 'info' declared here
    2080 |                 struct vfio_iommu_type1_info info;
         |                                              ^~~~
   In function '_copy_from_user',
       inlined from 'copy_from_user' at include/linux/uaccess.h:144:7,
       inlined from 'vfio_iommu_type1_ioctl.part.0' at drivers/vfio/vfio_iommu_type1.c:2104:7:
   include/linux/uaccess.h:112:17: warning: 'map' may be used uninitialized [-Wmaybe-uninitialized]
     112 |                 kasan_check_write(to, n);
         |                 ^~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/kasan-checks.h: In function 'vfio_iommu_type1_ioctl.part.0':
   include/linux/kasan-checks.h:7:6: note: by argument 1 of type 'const volatile void *' to 'kasan_check_write' declared here
       7 | void kasan_check_write(const volatile void *p, unsigned int size);
         |      ^~~~~~~~~~~~~~~~~
   drivers/vfio/vfio_iommu_type1.c:2098:49: note: 'map' declared here
    2098 |                 struct vfio_iommu_type1_dma_map map;
         |                                                 ^~~
   In function '_copy_from_user',
       inlined from 'copy_from_user' at include/linux/uaccess.h:144:7,
       inlined from 'vfio_iommu_type1_ioctl.part.0' at drivers/vfio/vfio_iommu_type1.c:2118:7:
   include/linux/uaccess.h:112:17: warning: 'unmap' may be used uninitialized [-Wmaybe-uninitialized]
     112 |                 kasan_check_write(to, n);
         |                 ^~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/kasan-checks.h: In function 'vfio_iommu_type1_ioctl.part.0':
   include/linux/kasan-checks.h:7:6: note: by argument 1 of type 'const volatile void *' to 'kasan_check_write' declared here
       7 | void kasan_check_write(const volatile void *p, unsigned int size);
         |      ^~~~~~~~~~~~~~~~~
   drivers/vfio/vfio_iommu_type1.c:2113:51: note: 'unmap' declared here
    2113 |                 struct vfio_iommu_type1_dma_unmap unmap;
         |                                                   ^~~~~
   In function '_copy_from_user',
       inlined from 'copy_from_user' at include/linux/uaccess.h:144:7,
       inlined from 'vfio_iommu_type1_ioctl.part.0' at drivers/vfio/vfio_iommu_type1.c:2136:7:
...
...
include/linux/uaccess.h:112:17: warning: 'bind' may be used uninitialized [-Wmaybe-uninitialized]
112 |                 kasan_check_write(to, n);
         |                 ^~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/kasan-checks.h: In function 'vfio_iommu_type1_ioctl.part.0':
   include/linux/kasan-checks.h:7:6: note: by argument 1 of type 'const volatile void *' to 'kasan_check_write' declared here
       7 | void kasan_check_write(const volatile void *p, unsigned int size);
         |      ^~~~~~~~~~~~~~~~~
   drivers/vfio/vfio_iommu_type1.c:2132:46: note: 'bind' declared here
    2132 |                 struct vfio_iommu_type1_bind bind;
         |                                              ^~~~
   In function '_copy_from_user',
       inlined from 'copy_from_user' at include/linux/uaccess.h:144:7,
       inlined from 'vfio_iommu_type1_ioctl.part.0' at drivers/vfio/vfio_iommu_type1.c:2155:7:
...
...
include/linux/uaccess.h:112:17: warning: 'bind' may be used uninitialized [-Wmaybe-uninitialized]
112 |                 kasan_check_write(to, n);
         |                 ^~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/kasan-checks.h: In function 'vfio_iommu_type1_ioctl.part.0':
   include/linux/kasan-checks.h:7:6: note: by argument 1 of type 'const volatile void *' to 'kasan_check_write' declared here
       7 | void kasan_check_write(const volatile void *p, unsigned int size);
         |      ^~~~~~~~~~~~~~~~~
   drivers/vfio/vfio_iommu_type1.c:2151:46: note: 'bind' declared here
    2151 |                 struct vfio_iommu_type1_bind bind;
         |                                              ^~~~
vim +/bind +112 include/linux/uaccess.h
d597580d373774 Al Viro        2017-03-20  104  
d597580d373774 Al Viro        2017-03-20  105  #ifdef INLINE_COPY_FROM_USER
d597580d373774 Al Viro        2017-03-20  106  static inline unsigned long
d597580d373774 Al Viro        2017-03-20  107  _copy_from_user(void *to, const void __user *from, unsigned long n)
d597580d373774 Al Viro        2017-03-20  108  {
d597580d373774 Al Viro        2017-03-20  109  	unsigned long res = n;
9c5f6908de03a4 Al Viro        2017-06-29  110  	might_fault();
4983cb67a383a7 Linus Torvalds 2019-02-14  111  	if (likely(access_ok(from, n))) {
9c5f6908de03a4 Al Viro        2017-06-29 @112  		kasan_check_write(to, n);
d597580d373774 Al Viro        2017-03-20  113  		res = raw_copy_from_user(to, from, n);
9c5f6908de03a4 Al Viro        2017-06-29  114  	}
d597580d373774 Al Viro        2017-03-20  115  	if (unlikely(res))
d597580d373774 Al Viro        2017-03-20  116  		memset(to + (n - res), 0, res);
d597580d373774 Al Viro        2017-03-20  117  	return res;
d597580d373774 Al Viro        2017-03-20  118  }
d597580d373774 Al Viro        2017-03-20  119  #else
d597580d373774 Al Viro        2017-03-20  120  extern unsigned long
d597580d373774 Al Viro        2017-03-20  121  _copy_from_user(void *, const void __user *, unsigned long);
d597580d373774 Al Viro        2017-03-20  122  #endif
d597580d373774 Al Viro        2017-03-20  123
:::::: The code at line 112 was first introduced by commit
:::::: 9c5f6908de03a4f52ba7364b11fcd6116225480c copy_{from,to}_user(): move kasan checks and might_fault() out-of-line
:::::: TO: Al Viro viro@zeniv.linux.org.uk
:::::: CC: Al Viro viro@zeniv.linux.org.uk
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