kernel/trace/trace_events_synth.c:436:68: sparse: sparse: incorrect type in argument 2 (different address spaces)

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

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head:   5a6a09e97199d6600d31383055f9d43fbbcbe86f
commit: 0934ae9977c27133449b6dd8c6213970e7eece38 tracing: Fix reading strings from synthetic events
date:   1 year, 1 month ago
config: x86_64-randconfig-x014-20230805 (https://download.01.org/0day-ci/archive/20231101/202311010013.fm8WTxa5-lkp@intel.com/config)
compiler: gcc-12 (Debian 12.2.0-14) 12.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20231101/202311010013.fm8WTxa5-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/202311010013.fm8WTxa5-lkp@intel.com/

sparse warnings: (new ones prefixed by >>)
>> kernel/trace/trace_events_synth.c:436:68: sparse: sparse: incorrect type in argument 2 (different address spaces) @@     expected void const [noderef] __user *unsafe_addr @@     got char *str_val @@
   kernel/trace/trace_events_synth.c:436:68: sparse:     expected void const [noderef] __user *unsafe_addr
   kernel/trace/trace_events_synth.c:436:68: sparse:     got char *str_val

vim +436 kernel/trace/trace_events_synth.c

   404	
   405	static unsigned int trace_string(struct synth_trace_event *entry,
   406					 struct synth_event *event,
   407					 char *str_val,
   408					 bool is_dynamic,
   409					 unsigned int data_size,
   410					 unsigned int *n_u64)
   411	{
   412		unsigned int len = 0;
   413		char *str_field;
   414		int ret;
   415	
   416		if (is_dynamic) {
   417			u32 data_offset;
   418	
   419			data_offset = offsetof(typeof(*entry), fields);
   420			data_offset += event->n_u64 * sizeof(u64);
   421			data_offset += data_size;
   422	
   423			len = kern_fetch_store_strlen((unsigned long)str_val);
   424	
   425			data_offset |= len << 16;
   426			*(u32 *)&entry->fields[*n_u64] = data_offset;
   427	
   428			ret = kern_fetch_store_string((unsigned long)str_val, &entry->fields[*n_u64], entry);
   429	
   430			(*n_u64)++;
   431		} else {
   432			str_field = (char *)&entry->fields[*n_u64];
   433	
   434	#ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
   435			if ((unsigned long)str_val < TASK_SIZE)
 > 436				ret = strncpy_from_user_nofault(str_field, str_val, STR_VAR_LEN_MAX);
   437			else
   438	#endif
   439				ret = strncpy_from_kernel_nofault(str_field, str_val, STR_VAR_LEN_MAX);
   440	
   441			if (ret < 0)
   442				strcpy(str_field, FAULT_STRING);
   443	
   444			(*n_u64) += STR_VAR_LEN_MAX / sizeof(u64);
   445		}
   446	
   447		return len;
   448	}
   449	

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