Re: [PATCH] crash: Support high memory reservation for range syntax

[kernel test robot]

Hi Youling,

kernel test robot noticed the following build errors:

[auto build test ERROR on akpm-mm/mm-everything]
[also build test ERROR on linus/master v7.0 next-20260414]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Youling-Tang/crash-Support-high-memory-reservation-for-range-syntax/20260414-205035
base:   https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-everything
patch link:    https://lore.kernel.org/r/20260404074103.506793-1-youling.tang%40linux.dev
patch subject: [PATCH] crash: Support high memory reservation for range syntax
config: s390-defconfig (https://download.01.org/0day-ci/archive/20260415/202604150941.oDguaP7A-lkp@xxxxxxxxx/config)
compiler: clang version 23.0.0git (https://github.com/llvm/llvm-project 5bac06718f502014fade905512f1d26d578a18f3)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260415/202604150941.oDguaP7A-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/202604150941.oDguaP7A-lkp@xxxxxxxxx/

All errors (new ones prefixed by >>):

   kernel/crash_reserve.c:264:19: warning: expression which evaluates to zero treated as a null pointer constant of type 'char *' [-Wnon-literal-null-conversion]
     264 |         char *first_gt = false;
         |                          ^~~~~
>> kernel/crash_reserve.c:324:16: error: use of undeclared identifier 'DEFAULT_CRASH_KERNEL_LOW_SIZE'
     324 |                         *low_size = DEFAULT_CRASH_KERNEL_LOW_SIZE;
         |                                     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   1 warning and 1 error generated.


vim +/DEFAULT_CRASH_KERNEL_LOW_SIZE +324 kernel/crash_reserve.c

   282	
   283	static int __init __parse_crashkernel(char *cmdline,
   284				     unsigned long long system_ram,
   285				     unsigned long long *crash_size,
   286				     unsigned long long *crash_base,
   287				     const char *suffix,
   288				     bool *high,
   289				     unsigned long long *low_size)
   290	{
   291		char *first_colon, *first_space;
   292		char *ck_cmdline;
   293		char *name = "crashkernel=";
   294		unsigned long long boundary = 0;
   295		int ret;
   296	
   297		BUG_ON(!crash_size || !crash_base);
   298		*crash_size = 0;
   299		*crash_base = 0;
   300	
   301		ck_cmdline = get_last_crashkernel(cmdline, name, suffix);
   302		if (!ck_cmdline)
   303			return -ENOENT;
   304	
   305		ck_cmdline += strlen(name);
   306	
   307		if (suffix)
   308			return parse_crashkernel_suffix(ck_cmdline, crash_size,
   309					suffix);
   310		/*
   311		 * if the commandline contains a ':', then that's the extended
   312		 * syntax -- if not, it must be the classic syntax
   313		 */
   314		first_colon = strchr(ck_cmdline, ':');
   315		first_space = strchr(ck_cmdline, ' ');
   316		if (first_colon && (!first_space || first_colon < first_space)) {
   317			ret = parse_crashkernel_mem(ck_cmdline, system_ram,
   318					crash_size, crash_base);
   319	
   320			/* Handle optional ',>boundary' condition for range ':' syntax only. */
   321			parse_crashkernel_boundary(ck_cmdline, &boundary);
   322			if (!ret && *crash_size > boundary) {
   323				*high = true;
 > 324				*low_size = DEFAULT_CRASH_KERNEL_LOW_SIZE;
   325			}
   326	
   327			return ret;
   328		}
   329	
   330		return parse_crashkernel_simple(ck_cmdline, crash_size, crash_base);
   331	}
   332	

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