[PATCH perf/core 3/4] perf-probe: Fix to probe on gcc generated functions in modules

[Masami Hiramatsu]

Fix to probe on gcc generated functions on modules. Since
probing on a module is based on its symbol name, it should
be adjusted on actual symbols.

E.g. without this fix, perf probe shows probe definition
on non-exist symbol as below.

  $ perf probe -m build-x86_64/net/netfilter/nf_nat.ko -F in_range*
  in_range.isra.12
  $ perf probe -m build-x86_64/net/netfilter/nf_nat.ko -D in_range
  p:probe/in_range nf_nat:in_range+0

With this fix, perf probe correctly shows a probe on
gcc-generated symbol.

  $ perf probe -m build-x86_64/net/netfilter/nf_nat.ko -D in_range
  p:probe/in_range nf_nat:in_range.isra.12+0

This also fixes same problem on online module as below.

  $ perf probe -m i915 -D assert_plane
  p:probe/assert_plane i915:assert_plane.constprop.134+0

Signed-off-by: Masami Hiramatsu 
---
 tools/perf/util/probe-event.c  |   45 ++--
 tools/perf/util/probe-finder.c |7 --
 tools/perf/util/probe-finder.h |3 +++
 3 files changed, 37 insertions(+), 18 deletions(-)

diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
index aa8a922..6a6f44d 100644
--- a/tools/perf/util/probe-event.c
+++ b/tools/perf/util/probe-event.c
@@ -698,18 +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, _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([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) {
@@ -719,6 +732,8 @@ static int add_module_to_probe_trace_events(struct 
probe_trace_event *tevs,
}
 
free(mod_name);
+   map__put(map);
+
return ret;
 }
 
@@ -776,7 +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;
 
@@ -784,7 +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);
 
@@ -828,30 +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);
+   ntevs = 0;
}
-   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 

[PATCH perf/core 3/4] perf-probe: Fix to probe on gcc generated functions in modules

[Masami Hiramatsu]

Fix to probe on gcc generated functions on modules. Since
probing on a module is based on its symbol name, it should
be adjusted on actual symbols.

E.g. without this fix, perf probe shows probe definition
on non-exist symbol as below.

  $ perf probe -m build-x86_64/net/netfilter/nf_nat.ko -F in_range*
  in_range.isra.12
  $ perf probe -m build-x86_64/net/netfilter/nf_nat.ko -D in_range
  p:probe/in_range nf_nat:in_range+0

With this fix, perf probe correctly shows a probe on
gcc-generated symbol.

  $ perf probe -m build-x86_64/net/netfilter/nf_nat.ko -D in_range
  p:probe/in_range nf_nat:in_range.isra.12+0

This also fixes same problem on online module as below.

  $ perf probe -m i915 -D assert_plane
  p:probe/assert_plane i915:assert_plane.constprop.134+0

Signed-off-by: Masami Hiramatsu 
---
 tools/perf/util/probe-event.c  |   45 ++--
 tools/perf/util/probe-finder.c |7 --
 tools/perf/util/probe-finder.h |3 +++
 3 files changed, 37 insertions(+), 18 deletions(-)

diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
index aa8a922..6a6f44d 100644
--- a/tools/perf/util/probe-event.c
+++ b/tools/perf/util/probe-event.c
@@ -698,18 +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, _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([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) {
@@ -719,6 +732,8 @@ static int add_module_to_probe_trace_events(struct 
probe_trace_event *tevs,
}
 
free(mod_name);
+   map__put(map);
+
return ret;
 }
 
@@ -776,7 +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;
 
@@ -784,7 +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);
 
@@ -828,30 +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);
+   ntevs = 0;
}
-   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",