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Date: Wed, 4 Jan 2017 12:31:39 +0900
From: Masami Hiramatsu <mhiramat@...nel.org>
To: Arnaldo Carvalho de Melo <acme@...nel.org>
Cc: Masami Hiramatsu <mhiramat@...nel.org>,
linux-kernel@...r.kernel.org, Jiri Olsa <jolsa@...hat.com>,
Peter Zijlstra <peterz@...radead.org>,
Ingo Molnar <mingo@...hat.com>,
Namhyung Kim <namhyung@...nel.org>
Subject: [PATCH perf/core 3/3] perf-probe: Fix to probe on gcc generated functions in modules
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
-----
Signed-off-by: Masami Hiramatsu <mhiramat@...nel.org>
---
tools/perf/util/probe-event.c | 38 +++++++++++++++++++++++---------------
tools/perf/util/probe-finder.c | 2 +-
tools/perf/util/probe-finder.h | 2 ++
3 files changed, 26 insertions(+), 16 deletions(-)
diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
index 4a57c8a..f75c99a 100644
--- a/tools/perf/util/probe-event.c
+++ b/tools/perf/util/probe-event.c
@@ -682,15 +682,19 @@ 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;
int i, ret = 0;
char *mod_name = NULL;
if (!module)
return 0;
+ debuginfo__get_text_offset(dinfo, &text_offs);
mod_name = find_module_name(module);
for (i = 0; i < ntevs; i++) {
@@ -700,9 +704,15 @@ static int add_module_to_probe_trace_events(struct probe_trace_event *tevs,
ret = -ENOMEM;
break;
}
+ /* kernel module needs a special care to adjust addresses */
+ tevs[i].point.address -= (unsigned long)text_offs;
}
free(mod_name);
+
+ if (!ret)
+ ret = post_process_offline_probe_trace_events(tevs, ntevs,
+ module);
return ret;
}
@@ -760,7 +770,7 @@ 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 +778,8 @@ 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 +823,27 @@ 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",
synthesize_perf_probe_point(&pev->point));
return -ENOENT;
- }
- /* Error path : ntevs < 0 */
- pr_debug("An error occurred in debuginfo analysis (%d).\n", ntevs);
- if (ntevs < 0) {
+ } else if (ntevs < 0) {
+ /* Error path : ntevs < 0 */
+ pr_debug("An error occurred in debuginfo analysis (%d).\n", ntevs);
if (ntevs == -EBADF)
pr_warning("Warning: No dwarf info found in the vmlinux - "
"please rebuild kernel with CONFIG_DEBUG_INFO=y.\n");
diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c
index df4debe..6dede24 100644
--- a/tools/perf/util/probe-finder.c
+++ b/tools/perf/util/probe-finder.c
@@ -1501,7 +1501,7 @@ 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)
{
int n, i;
Elf32_Word shndx;
diff --git a/tools/perf/util/probe-finder.h b/tools/perf/util/probe-finder.h
index f1d8558..1e03bbb 100644
--- a/tools/perf/util/probe-finder.h
+++ b/tools/perf/util/probe-finder.h
@@ -46,6 +46,8 @@ 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);
+
/* Find a line range */
int debuginfo__find_line_range(struct debuginfo *dbg, struct line_range *lr);
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