Re: [PATCH v3 3/5] tracing: fprobe: support comma-separated symbols and :entry/:exit

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

Hi Ryan,

kernel test robot noticed the following build errors:

[auto build test ERROR on v6.17]
[also build test ERROR on linus/master next-20251010]
[cannot apply to trace/for-next]
[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/Ryan-Chung/docs-tracing-fprobe-document-list-filters-and-entry-exit/20251010-111713
base:   v6.17
patch link:    https://lore.kernel.org/r/20251004235001.133111-4-seokwoo.chung130%40gmail.com
patch subject: [PATCH v3 3/5] tracing: fprobe: support comma-separated symbols and :entry/:exit
config: x86_64-rhel-9.4 (https://download.01.org/0day-ci/archive/20251010/202510102331.y36ENO9m-lkp@intel.com/config)
compiler: gcc-14 (Debian 14.2.0-19) 14.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20251010/202510102331.y36ENO9m-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/202510102331.y36ENO9m-lkp@intel.com/

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

   kernel/trace/trace_fprobe.c: In function 'parse_fprobe_spec':
>> kernel/trace/trace_fprobe.c:274:28: error: assignment of read-only location '*p'
     274 |                         *p = '\0';
         |                            ^
   kernel/trace/trace_fprobe.c:276:28: error: assignment of read-only location '*p'
     276 |                         *p = '\0';
         |                            ^
   kernel/trace/trace_fprobe.c: In function 'parse_symbol_and_return':
>> kernel/trace/trace_fprobe.c:1281:31: error: 'nofilter' undeclared (first use in this function); did you mean 'filter'?
    1281 |         char *filter = NULL; *nofilter = NULL;
         |                               ^~~~~~~~
         |                               filter
   kernel/trace/trace_fprobe.c:1281:31: note: each undeclared identifier is reported only once for each function it appears in
   kernel/trace/trace_fprobe.c: In function 'trace_fprobe_create_internal':
   kernel/trace/trace_fprobe.c:1355:14: warning: unused variable 'has_wild' [-Wunused-variable]
    1355 |         bool has_wild = false;
         |              ^~~~~~~~
   kernel/trace/trace_fprobe.c: At top level:
>> kernel/trace/trace_fprobe.c:1275:12: warning: 'parse_symbol_and_return' defined but not used [-Wunused-function]
    1275 | static int parse_symbol_and_return(int argc, const char *argv[],
         |            ^~~~~~~~~~~~~~~~~~~~~~~


vim +274 kernel/trace/trace_fprobe.c

   233	
   234	static int parse_fprobe_spec(const char *in, bool is_tracepoint,
   235			char **base, bool *is_return, bool *list_mode,
   236			char **filter, char **nofilter)
   237	{
   238		const char *p;
   239		char *work = NULL;
   240		char *b = NULL, *f = NULL, *nf = NULL;
   241		bool legacy_ret = false;
   242		bool list = false;
   243		int ret = 0;
   244	
   245		if (!in || !base || !is_return || !list_mode || !filter || !nofilter)
   246			return -EINVAL;
   247	
   248		*base = NULL; *filter = NULL; *nofilter = NULL;
   249		*is_return = false; *list_mode = false;
   250	
   251		if (is_tracepoint) {
   252			if (strchr(in, ',') || strchr(in, ':'))
   253				return -EINVAL;
   254			if (strstr(in, "%return"))
   255				return -EINVAL;
   256			for (p = in; *p; p++)
   257				if (!isalnum(*p) && *p != '_')
   258					return -EINVAL;
   259			b = kstrdup(in, GFP_KERNEL);
   260			if (!b)
   261				return -ENOMEM;
   262			*base = b;
   263			return 0;
   264		}
   265	
   266		work = kstrdup(in, GFP_KERNEL);
   267		if (!work)
   268			return -ENOMEM;
   269	
   270		p = strstr(work, "%return");
   271		if (p) {
   272			if (!strcmp(p, ":exit")) {
   273				*is_return = true;
 > 274				*p = '\0';
   275			} else if (!strcmp(p, ":entry")) {
   276				*p = '\0';
   277			} else {
   278				ret = -EINVAL;
   279				goto out;
   280			}
   281		}
   282	
   283		list = !!strchr(work, ',') || has_wildcard(work);
   284		if (legacy_ret)
   285			*is_return = true;
   286	
   287		b = kstrdup(work, GFP_KERNEL);
   288		if (!b) {
   289			ret = -ENOMEM;
   290			goto out;
   291		}
   292	
   293		if (list) {
   294			char *tmp = b, *tok;
   295			size_t fsz = strlen(b) + 1, nfsz = strlen(b) + 1;
   296	
   297			f = kzalloc(fsz, GFP_KERNEL);
   298			nf = kzalloc(nfsz, GFP_KERNEL);
   299			if (!f || !nf) {
   300				ret = -ENOMEM;
   301				goto out;
   302			}
   303	
   304			while ((tok = strsep(&tmp, ",")) != NULL) {
   305				char *dst;
   306				bool neg = (*tok == '!');
   307	
   308				if (*tok == '\0')
   309					continue;
   310				if (neg)
   311					tok++;
   312				dst = neg ? nf : f;
   313				if (dst[0] != '\0')
   314					strcat(dst, ",");
   315				strcat(dst, tok);
   316			}
   317			*list_mode = true;
   318		}
   319	
   320		*base = b; b = NULL;
   321		*filter = f; f = NULL;
   322		*nofilter = nf; nf = NULL;
   323	
   324	out:
   325		kfree(work);
   326		kfree(b);
   327		kfree(f);
   328		kfree(nf);
   329		return ret;
   330	}
   331	

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