Re: [PATCH v5] tracing/eprobes: Allow use of BTF names to dereference pointers

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

Hi Steven,

kernel test robot noticed the following build errors:

[auto build test ERROR on trace/for-next]
[also build test ERROR on linus/master v7.1-rc4 next-20260519]
[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/Steven-Rostedt/tracing-eprobes-Allow-use-of-BTF-names-to-dereference-pointers/20260520-011353
base:   https://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace for-next
patch link:    https://lore.kernel.org/r/20260519130144.40e71a00%40fedora
patch subject: [PATCH v5] tracing/eprobes: Allow use of BTF names to dereference pointers
config: s390-randconfig-r071-20260520 (https://download.01.org/0day-ci/archive/20260520/202605200427.0xXjKghz-lkp@intel.com/config)
compiler: s390-linux-gcc (GCC) 8.5.0
smatch: v0.5.0-9185-gbcc58b9c
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260520/202605200427.0xXjKghz-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/202605200427.0xXjKghz-lkp@intel.com/

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

   kernel/trace/trace_probe.c: In function 'parse_probe_vars':
>> kernel/trace/trace_probe.c:1035:7: error: implicit declaration of function 'parse_trace_event'; did you mean 'parse_trace_event_arg'? [-Werror=implicit-function-declaration]
      if (parse_trace_event(arg, code, ctx) < 0)
          ^~~~~~~~~~~~~~~~~
          parse_trace_event_arg
   kernel/trace/trace_probe.c: In function 'sprint_nth_btf_arg':
>> kernel/trace/trace_probe.c:1803:20: error: implicit declaration of function 'ctx_btf' [-Werror=implicit-function-declaration]
     struct btf *btf = ctx_btf(ctx);
                       ^~~~~~~
>> kernel/trace/trace_probe.c:1803:20: warning: initialization of 'struct btf *' from 'int' makes pointer from integer without a cast [-Wint-conversion]
   At top level:
>> kernel/trace/trace_probe.c:318:12: warning: 'parse_trace_event_arg' defined but not used [-Wunused-function]
    static int parse_trace_event_arg(char *arg, struct fetch_insn *code,
               ^~~~~~~~~~~~~~~~~~~~~
   cc1: some warnings being treated as errors


vim +1035 kernel/trace/trace_probe.c

  1020	
  1021	/* Parse $vars. @orig_arg points '$', which syncs to @ctx->offset */
  1022	static int parse_probe_vars(char *orig_arg, const struct fetch_type *t,
  1023				    struct fetch_insn **pcode,
  1024				    struct fetch_insn *end,
  1025				    struct traceprobe_parse_context *ctx)
  1026	{
  1027		struct fetch_insn *code = *pcode;
  1028		int err = TP_ERR_BAD_VAR;
  1029		char *arg = orig_arg + 1;
  1030		unsigned long param;
  1031		int ret = 0;
  1032		int len;
  1033	
  1034		if (ctx->flags & TPARG_FL_TEVENT) {
> 1035			if (parse_trace_event(arg, code, ctx) < 0)
  1036				goto inval;
  1037			return 0;
  1038		}
  1039	
  1040		if (str_has_prefix(arg, "retval")) {
  1041			if (!(ctx->flags & TPARG_FL_RETURN)) {
  1042				err = TP_ERR_RETVAL_ON_PROBE;
  1043				goto inval;
  1044			}
  1045			if (!(ctx->flags & TPARG_FL_KERNEL) ||
  1046			    !IS_ENABLED(CONFIG_PROBE_EVENTS_BTF_ARGS)) {
  1047				code->op = FETCH_OP_RETVAL;
  1048				return 0;
  1049			}
  1050			return parse_btf_arg(orig_arg, pcode, end, ctx);
  1051		}
  1052	
  1053		len = str_has_prefix(arg, "stack");
  1054		if (len) {
  1055	
  1056			if (arg[len] == '\0') {
  1057				code->op = FETCH_OP_STACKP;
  1058				return 0;
  1059			}
  1060	
  1061			if (isdigit(arg[len])) {
  1062				ret = kstrtoul(arg + len, 10, &param);
  1063				if (ret)
  1064					goto inval;
  1065	
  1066				if ((ctx->flags & TPARG_FL_KERNEL) &&
  1067				    param > PARAM_MAX_STACK) {
  1068					err = TP_ERR_BAD_STACK_NUM;
  1069					goto inval;
  1070				}
  1071				code->op = FETCH_OP_STACK;
  1072				code->param = (unsigned int)param;
  1073				return 0;
  1074			}
  1075			goto inval;
  1076		}
  1077	
  1078		if (strcmp(arg, "comm") == 0 || strcmp(arg, "COMM") == 0) {
  1079			code->op = FETCH_OP_COMM;
  1080			return 0;
  1081		}
  1082	

--
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https://github.com/intel/lkp-tests/wiki