Hi Robin,

[auto build test WARNING on char-misc/char-misc-testing]
[also build test WARNING on v4.10-rc2 next-20170104]
[if your patch is applied to the wrong git tree, please drop us a note to help 
improve the system]

url:    
https://github.com/0day-ci/linux/commits/Robin-Murphy/drivers-char-mem-Fix-thinko-in-kmem-address-checks/20170104-235754
config: tile-allmodconfig (attached as .config)
compiler: tilegx-linux-gcc (GCC) 4.6.2
reproduce:
        wget 
https://git.kernel.org/cgit/linux/kernel/git/wfg/lkp-tests.git/plain/sbin/make.cross
 -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # save the attached .config to linux build tree
        make.cross ARCH=tile 

All warnings (new ones prefixed by >>):

   drivers/char/mem.c: In function 'read_kmem':
>> drivers/char/mem.c:384:2: warning: passing argument 1 of 'kaddr_to_pfn' 
>> makes pointer from integer without a cast [enabled by default]
   arch/tile/include/asm/page.h:281:29: note: expected 'const volatile void *' 
but argument is of type 'long unsigned int'
   drivers/char/mem.c: In function 'write_kmem':
   drivers/char/mem.c:515:2: warning: passing argument 1 of 'kaddr_to_pfn' 
makes pointer from integer without a cast [enabled by default]
   arch/tile/include/asm/page.h:281:29: note: expected 'const volatile void *' 
but argument is of type 'long unsigned int'

vim +/kaddr_to_pfn +384 drivers/char/mem.c

   368  
   369          vma->vm_pgoff = pfn;
   370          return mmap_mem(file, vma);
   371  }
   372  
   373  /*
   374   * This function reads the *virtual* memory as seen by the kernel.
   375   */
   376  static ssize_t read_kmem(struct file *file, char __user *buf,
   377                           size_t count, loff_t *ppos)
   378  {
   379          unsigned long p = *ppos;
   380          ssize_t low_count, read, sz;
   381          char *kbuf; /* k-addr because vread() takes vmlist_lock rwlock 
*/
   382          int err = 0;
   383  
 > 384          if (!virt_addr_valid(p))
   385                  return -EIO;
   386  
   387          read = 0;
   388          if (p < (unsigned long) high_memory) {
   389                  low_count = count;
   390                  if (count > (unsigned long)high_memory - p)
   391                          low_count = (unsigned long)high_memory - p;
   392  

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

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