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

kernel test robot
2026-04-15T01:43:42Z

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@intel.com/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@intel.com/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@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202604150941.oDguaP7A-lkp@intel.com/

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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