Merge tag 'perf-urgent-for-mingo-4.10-20170117' of...

Merge tag 'perf-urgent-for-mingo-4.10-20170117' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux into perf/urgent

Pull 'perf probe' fixes from Arnaldo Carvalho de Melo <acme@redhat.com>

  - Show correct locations for 'perf probe' on modules (Masami Hiramatsu)

  - Correctly handle 'perf probe's on GCC generated functions in modules (Masami Hiramatsu)
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>

tools/perf/util/probe-event.c

@@ -610,6 +610,33 @@ static int find_perf_probe_point_from_dwarf(struct probe_trace_point *tp,
 	return ret ? : -ENOENT;
 }
 
+/* Adjust symbol name and address */
+static int post_process_probe_trace_point(struct probe_trace_point *tp,
+					   struct map *map, unsigned long offs)
+{
+	struct symbol *sym;
+	u64 addr = tp->address + tp->offset - offs;
+
+	sym = map__find_symbol(map, addr);
+	if (!sym)
+		return -ENOENT;
+
+	if (strcmp(sym->name, tp->symbol)) {
+		/* If we have no realname, use symbol for it */
+		if (!tp->realname)
+			tp->realname = tp->symbol;
+		else
+			free(tp->symbol);
+		tp->symbol = strdup(sym->name);
+		if (!tp->symbol)
+			return -ENOMEM;
+	}
+	tp->offset = addr - sym->start;
+	tp->address -= offs;
+
+	return 0;
+}
+
 /*
  * Rename DWARF symbols to ELF symbols -- gcc sometimes optimizes functions
  * and generate new symbols with suffixes such as .constprop.N or .isra.N
@@ -622,11 +649,9 @@ static int
 post_process_offline_probe_trace_events(struct probe_trace_event *tevs,
 					int ntevs, const char *pathname)
 {
-	struct symbol *sym;
 	struct map *map;
 	unsigned long stext = 0;
-	u64 addr;
-	int i;
+	int i, ret = 0;
 
 	/* Prepare a map for offline binary */
 	map = dso__new_map(pathname);
@@ -636,23 +661,14 @@ post_process_offline_probe_trace_events(struct probe_trace_event *tevs,
 	}
 
 	for (i = 0; i < ntevs; i++) {
-		addr = tevs[i].point.address + tevs[i].point.offset - stext;
-		sym = map__find_symbol(map, addr);
-		if (!sym)
-			continue;
-		if (!strcmp(sym->name, tevs[i].point.symbol))
-			continue;
-		/* If we have no realname, use symbol for it */
-		if (!tevs[i].point.realname)
-			tevs[i].point.realname = tevs[i].point.symbol;
-		else
-			free(tevs[i].point.symbol);
-		tevs[i].point.symbol = strdup(sym->name);
-		tevs[i].point.offset = addr - sym->start;
+		ret = post_process_probe_trace_point(&tevs[i].point,
+						     map, stext);
+		if (ret < 0)
+			break;
 	}
 	map__put(map);
 
-	return 0;
+	return ret;
 }
 
 static int add_exec_to_probe_trace_events(struct probe_trace_event *tevs,
@@ -682,18 +698,31 @@ static int add_exec_to_probe_trace_events(struct probe_trace_event *tevs,
 	return ret;
 }
 
-static int add_module_to_probe_trace_events(struct probe_trace_event *tevs,
-					    int ntevs, const char *module)
+static int
+post_process_module_probe_trace_events(struct probe_trace_event *tevs,
+				       int ntevs, const char *module,
+				       struct debuginfo *dinfo)
 {
+	Dwarf_Addr text_offs = 0;
 	int i, ret = 0;
 	char *mod_name = NULL;
+	struct map *map;
 
 	if (!module)
 		return 0;
 
-	mod_name = find_module_name(module);
+	map = get_target_map(module, false);
+	if (!map || debuginfo__get_text_offset(dinfo, &text_offs, true) < 0) {
+		pr_warning("Failed to get ELF symbols for %s\n", module);
+		return -EINVAL;
+	}
 
+	mod_name = find_module_name(module);
 	for (i = 0; i < ntevs; i++) {
+		ret = post_process_probe_trace_point(&tevs[i].point,
+						map, (unsigned long)text_offs);
+		if (ret < 0)
+			break;
 		tevs[i].point.module =
 			strdup(mod_name ? mod_name : module);
 		if (!tevs[i].point.module) {
@@ -703,6 +732,8 @@ static int add_module_to_probe_trace_events(struct probe_trace_event *tevs,
 	}
 
 	free(mod_name);
+	map__put(map);
+
 	return ret;
 }
 
@@ -760,7 +791,7 @@ arch__post_process_probe_trace_events(struct perf_probe_event *pev __maybe_unuse
 static int post_process_probe_trace_events(struct perf_probe_event *pev,
 					   struct probe_trace_event *tevs,
 					   int ntevs, const char *module,
-					   bool uprobe)
+					   bool uprobe, struct debuginfo *dinfo)
 {
 	int ret;
 
@@ -768,7 +799,8 @@ static int post_process_probe_trace_events(struct perf_probe_event *pev,
 		ret = add_exec_to_probe_trace_events(tevs, ntevs, module);
 	else if (module)
 		/* Currently ref_reloc_sym based probe is not for drivers */
-		ret = add_module_to_probe_trace_events(tevs, ntevs, module);
+		ret = post_process_module_probe_trace_events(tevs, ntevs,
+							     module, dinfo);
 	else
 		ret = post_process_kernel_probe_trace_events(tevs, ntevs);
 
@@ -812,30 +844,27 @@ static int try_to_find_probe_trace_events(struct perf_probe_event *pev,
 		}
 	}
 
-	debuginfo__delete(dinfo);
-
 	if (ntevs > 0) {	/* Succeeded to find trace events */
 		pr_debug("Found %d probe_trace_events.\n", ntevs);
 		ret = post_process_probe_trace_events(pev, *tevs, ntevs,
-						pev->target, pev->uprobes);
+					pev->target, pev->uprobes, dinfo);
 		if (ret < 0 || ret == ntevs) {
+			pr_debug("Post processing failed or all events are skipped. (%d)\n", ret);
 			clear_probe_trace_events(*tevs, ntevs);
 			zfree(tevs);
-		}
-		if (ret != ntevs)
-			return ret < 0 ? ret : ntevs;
 			ntevs = 0;
-		/* Fall through */
+		}
 	}
 
+	debuginfo__delete(dinfo);
+
 	if (ntevs == 0)	{	/* No error but failed to find probe point. */
 		pr_warning("Probe point '%s' not found.\n",
 			   synthesize_perf_probe_point(&pev->point));
 		return -ENOENT;
-	}
+	} else if (ntevs < 0) {
 		/* Error path : ntevs < 0 */
 		pr_debug("An error occurred in debuginfo analysis (%d).\n", ntevs);
-	if (ntevs < 0) {
 		if (ntevs == -EBADF)
 			pr_warning("Warning: No dwarf info found in the vmlinux - "
 				"please rebuild kernel with CONFIG_DEBUG_INFO=y.\n");

tools/perf/util/probe-finder.c

@@ -1501,7 +1501,8 @@ int debuginfo__find_available_vars_at(struct debuginfo *dbg,
 }
 
 /* For the kernel module, we need a special code to get a DIE */
-static int debuginfo__get_text_offset(struct debuginfo *dbg, Dwarf_Addr *offs)
+int debuginfo__get_text_offset(struct debuginfo *dbg, Dwarf_Addr *offs,
+				bool adjust_offset)
 {
 	int n, i;
 	Elf32_Word shndx;
@@ -1530,6 +1531,8 @@ static int debuginfo__get_text_offset(struct debuginfo *dbg, Dwarf_Addr *offs)
 			if (!shdr)
 				return -ENOENT;
 			*offs = shdr->sh_addr;
+			if (adjust_offset)
+				*offs -= shdr->sh_offset;
 		}
 	}
 	return 0;
@@ -1543,16 +1546,12 @@ int debuginfo__find_probe_point(struct debuginfo *dbg, unsigned long addr,
 	Dwarf_Addr _addr = 0, baseaddr = 0;
 	const char *fname = NULL, *func = NULL, *basefunc = NULL, *tmp;
 	int baseline = 0, lineno = 0, ret = 0;
-	bool reloc = false;
 
-retry:
+	/* We always need to relocate the address for aranges */
+	if (debuginfo__get_text_offset(dbg, &baseaddr, false) == 0)
+		addr += baseaddr;
 	/* Find cu die */
 	if (!dwarf_addrdie(dbg->dbg, (Dwarf_Addr)addr, &cudie)) {
-		if (!reloc && debuginfo__get_text_offset(dbg, &baseaddr) == 0) {
-			addr += baseaddr;
-			reloc = true;
-			goto retry;
-		}
 		pr_warning("Failed to find debug information for address %lx\n",
 			   addr);
 		ret = -EINVAL;

tools/perf/util/probe-finder.h

@@ -46,6 +46,9 @@ int debuginfo__find_trace_events(struct debuginfo *dbg,
 int debuginfo__find_probe_point(struct debuginfo *dbg, unsigned long addr,
 				struct perf_probe_point *ppt);
 
+int debuginfo__get_text_offset(struct debuginfo *dbg, Dwarf_Addr *offs,
+			       bool adjust_offset);
+
 /* Find a line range */
 int debuginfo__find_line_range(struct debuginfo *dbg, struct line_range *lr);