Re: [PATCH v2] kexec: add resriction on the kexec_load

[kbuild test robot <lkp@intel.com>]

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Hi,

[auto build test ERROR on stable/master]
[also build test ERROR on v4.7-rc7]
[cannot apply to next-20160721]
[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/zhongjiang/kexec-add-resriction-on-the-kexec_load/20160722-143017
base:   https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable.git master
config: i386-defconfig (attached as .config)
compiler: gcc-6 (Debian 6.1.1-9) 6.1.1 20160705
reproduce:
        # save the attached .config to linux build tree
        make ARCH=i386 

All error/warnings (new ones prefixed by >>):

   kernel/kexec_core.c: In function 'sanity_check_segment_list':
>> kernel/kexec_core.c:222:3: error: 'total' undeclared (first use in this function)
      total += image->segment[i].memsz;
      ^~~~~
   kernel/kexec_core.c:222:3: note: each undeclared identifier is reported only once for each function it appears in
>> kernel/kexec_core.c:151:16: warning: unused variable 'total_segments' [-Wunused-variable]
     unsigned long total_segments = 0;
                   ^~~~~~~~~~~~~~

vim +/total +222 kernel/kexec_core.c

   145					       gfp_t gfp_mask,
   146					       unsigned long dest);
   147	
   148	int sanity_check_segment_list(struct kimage *image)
   149	{
   150		int result, i;
 > 151		unsigned long total_segments = 0;
   152		unsigned long nr_segments = image->nr_segments;
   153	
   154		/*
   155		 * Verify we have good destination addresses.  The caller is
   156		 * responsible for making certain we don't attempt to load
   157		 * the new image into invalid or reserved areas of RAM.  This
   158		 * just verifies it is an address we can use.
   159		 *
   160		 * Since the kernel does everything in page size chunks ensure
   161		 * the destination addresses are page aligned.  Too many
   162		 * special cases crop of when we don't do this.  The most
   163		 * insidious is getting overlapping destination addresses
   164		 * simply because addresses are changed to page size
   165		 * granularity.
   166		 */
   167		result = -EADDRNOTAVAIL;
   168		for (i = 0; i < nr_segments; i++) {
   169			unsigned long mstart, mend;
   170	
   171			mstart = image->segment[i].mem;
   172			mend   = mstart + image->segment[i].memsz;
   173			if ((mstart & ~PAGE_MASK) || (mend & ~PAGE_MASK))
   174				return result;
   175			if (mend >= KEXEC_DESTINATION_MEMORY_LIMIT)
   176				return result;
   177		}
   178	
   179		/* Verify our destination addresses do not overlap.
   180		 * If we alloed overlapping destination addresses
   181		 * through very weird things can happen with no
   182		 * easy explanation as one segment stops on another.
   183		 */
   184		result = -EINVAL;
   185		for (i = 0; i < nr_segments; i++) {
   186			unsigned long mstart, mend;
   187			unsigned long j;
   188	
   189			mstart = image->segment[i].mem;
   190			mend   = mstart + image->segment[i].memsz;
   191			for (j = 0; j < i; j++) {
   192				unsigned long pstart, pend;
   193	
   194				pstart = image->segment[j].mem;
   195				pend   = pstart + image->segment[j].memsz;
   196				/* Do the segments overlap ? */
   197				if ((mend > pstart) && (mstart < pend))
   198					return result;
   199			}
   200		}
   201	
   202		/* Ensure our buffer sizes are strictly less than
   203		 * our memory sizes.  This should always be the case,
   204		 * and it is easier to check up front than to be surprised
   205		 * later on.
   206		 */
   207		result = -EINVAL;
   208		for (i = 0; i < nr_segments; i++) {
   209			if (image->segment[i].bufsz > image->segment[i].memsz)
   210				return result;
   211		}
   212	
   213		/* Verity all segment size donnot exceed the specified size.
   214		 * if segment size from user space is too large,  a large
   215		 * amount of time will be wasted when allocating page. so,
   216		 * softlockup may be come up.
   217		 */
   218		for (i = 0; i < nr_segments; i++) {
   219			if (image->segment[i].memsz > (totalram_pages / 2))
   220				return result;
   221	
 > 222			total += image->segment[i].memsz;
   223		}
   224	
   225		if (total > (totalram_pages / 2))

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