perf symbols: /proc/kallsyms does not sort module symbols

kallsyms__parse assumes that /proc/kallsyms is sorted and sets the end of the previous symbol to the start of the current one. Unfortunately module symbols are not sorted, eg: ffffffffa0081f30 t e1000_clean_rx_irq [e1000e] ffffffffa00817a0 t e1000_alloc_rx_buffers [e1000e] Some symbols end up with a negative length and others have a length larger than they should. This results in confusing perf output. We already have a function to fixup the end of zero length symbols so use that instead. Cc: Eric B Munson <emunson@mgebm.net> Cc: Ingo Molnar <mingo@elte.hu> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/20110824065242.969681349@samba.org Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

perf symbols: /proc/kallsyms does not sort module symbols
kallsyms__parse assumes that /proc/kallsyms is sorted and sets the end of the previous symbol to the start of the current one. Unfortunately module symbols are not sorted, eg: ffffffffa0081f30 t e1000_clean_rx_irq [e1000e] ffffffffa00817a0 t e1000_alloc_rx_buffers [e1000e] Some symbols end up with a negative length and others have a length larger than they should. This results in confusing perf output. We already have a function to fixup the end of zero length symbols so use that instead. Cc: Eric B Munson <emunson@mgebm.net> Cc: Ingo Molnar <mingo@elte.hu> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/20110824065242.969681349@samba.org Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Anton Blanchard · Arnaldo Carvalho de Melo
1 parent adb0918463
Showing 1 changed file with 11 additions and 22 deletions Side-by-side Diff
tools/perf/util/symbol.c
@@ -438,18 +438,11 @@
 	char *line = NULL;
 	size_t n;
 	int err = -1;
-	u64 prev_start = 0;
-	char prev_symbol_type = 0;
-	char *prev_symbol_name;
 	FILE *file = fopen(filename, "r");
  
 	if (file == NULL)
 		goto out_failure;
  
-	prev_symbol_name = malloc(KSYM_NAME_LEN);
-	if (prev_symbol_name == NULL)
-		goto out_close;
-
 	err = 0;
  
 	while (!feof(file)) {
  
  
@@ -480,24 +473,18 @@
 			break;
 		}
  
-		if (prev_symbol_type) {
-			u64 end = start;
-			if (end != prev_start)
-				--end;
-			err = process_symbol(arg, prev_symbol_name,
-					     prev_symbol_type, prev_start, end);
-			if (err)
-				break;
-		}
-
-		memcpy(prev_symbol_name, symbol_name, len + 1);
-		prev_symbol_type = symbol_type;
-		prev_start = start;
+		/*
+		 * module symbols are not sorted so we add all
+		 * symbols with zero length and rely on
+		 * symbols__fixup_end() to fix it up.
+		 */
+		err = process_symbol(arg, symbol_name,
+				     symbol_type, start, start);
+		if (err)
+			break;
 	}
  
-	free(prev_symbol_name);
 	free(line);
-out_close:
 	fclose(file);
 	return err;
  
@@ -702,6 +689,8 @@
  
 	if (dso__load_all_kallsyms(dso, filename, map) < 0)
 		return -1;
+
+	symbols__fixup_end(&dso->symbols[map->type]);
  
 	if (dso->kernel == DSO_TYPE_GUEST_KERNEL)
 		dso->symtab_type = SYMTAB__GUEST_KALLSYMS;
...	...	@@ -438,18 +438,11 @@
438	438	char *line = NULL;
439	439	size_t n;
440	440	int err = -1;
441		- u64 prev_start = 0;
442		- char prev_symbol_type = 0;
443		- char *prev_symbol_name;
444	441	FILE *file = fopen(filename, "r");
445	442
446	443	if (file == NULL)
447	444	goto out_failure;
448	445
449		- prev_symbol_name = malloc(KSYM_NAME_LEN);
450		- if (prev_symbol_name == NULL)
451		- goto out_close;
452		-
453	446	err = 0;
454	447
455	448	while (!feof(file)) {
456	449
457	450
...	...	@@ -480,24 +473,18 @@
480	473	break;
481	474	}
482	475
483		- if (prev_symbol_type) {
484		- u64 end = start;
485		- if (end != prev_start)
486		- --end;
487		- err = process_symbol(arg, prev_symbol_name,
488		- prev_symbol_type, prev_start, end);
489		- if (err)
490		- break;
491		- }
492		-
493		- memcpy(prev_symbol_name, symbol_name, len + 1);
494		- prev_symbol_type = symbol_type;
495		- prev_start = start;
	476	+ /*
	477	+ * module symbols are not sorted so we add all
	478	+ * symbols with zero length and rely on
	479	+ * symbols__fixup_end() to fix it up.
	480	+ */
	481	+ err = process_symbol(arg, symbol_name,
	482	+ symbol_type, start, start);
	483	+ if (err)
	484	+ break;
496	485	}
497	486
498		- free(prev_symbol_name);
499	487	free(line);
500		-out_close:
501	488	fclose(file);
502	489	return err;
503	490
...	...	@@ -702,6 +689,8 @@
702	689
703	690	if (dso__load_all_kallsyms(dso, filename, map) < 0)
704	691	return -1;
	692	+
	693	+ symbols__fixup_end(&dso->symbols[map->type]);
705	694
706	695	if (dso->kernel == DSO_TYPE_GUEST_KERNEL)
707	696	dso->symtab_type = SYMTAB__GUEST_KALLSYMS;