Commit 613f050d authored by Masami Hiramatsu's avatar Masami Hiramatsu Committed by Arnaldo Carvalho de Melo
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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

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: default avatarMasami Hiramatsu <mhiramat@kernel.org>
Tested-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/148411450673.9978.14905987549651656075.stgit@devbox


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent 3e96dac7

tools/perf/util/probe-event.c

+29 −16
Original line number Original line Diff line number Diff line
@@ -698,18 +698,31 @@ static int add_exec_to_probe_trace_events(struct probe_trace_event *tevs, 
	return ret;

	return ret;

}

}





static int add_module_to_probe_trace_events(struct probe_trace_event *tevs,

static int

					    int ntevs, const char *module)

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;

	int i, ret = 0;

	char *mod_name = NULL;

	char *mod_name = NULL;

	struct map *map;





	if (!module)

	if (!module)

		return 0;

		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++) {

	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 =

		tevs[i].point.module =

			strdup(mod_name ? mod_name : module);

			strdup(mod_name ? mod_name : module);

		if (!tevs[i].point.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);

	free(mod_name);

	map__put(map);



	return ret;

	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,

static int post_process_probe_trace_events(struct perf_probe_event *pev,

					   struct probe_trace_event *tevs,

					   struct probe_trace_event *tevs,

					   int ntevs, const char *module,

					   int ntevs, const char *module,

					   bool uprobe)

					   bool uprobe, struct debuginfo *dinfo)

{

{

	int ret;

	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);

		ret = add_exec_to_probe_trace_events(tevs, ntevs, module);

	else if (module)

	else if (module)

		/* Currently ref_reloc_sym based probe is not for drivers */

		/* 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

	else

		ret = post_process_kernel_probe_trace_events(tevs, ntevs);

		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 */

	if (ntevs > 0) {	/* Succeeded to find trace events */

		pr_debug("Found %d probe_trace_events.\n", ntevs);

		pr_debug("Found %d probe_trace_events.\n", ntevs);

		ret = post_process_probe_trace_events(pev, *tevs, ntevs,

		ret = post_process_probe_trace_events(pev, *tevs, ntevs,

						pev->target, pev->uprobes);

					pev->target, pev->uprobes, dinfo);

		if (ret < 0 || ret == ntevs) {

		if (ret < 0 || ret == ntevs) {

			pr_debug("Post processing failed or all events are skipped. (%d)\n", ret);

			clear_probe_trace_events(*tevs, ntevs);

			clear_probe_trace_events(*tevs, ntevs);

			zfree(tevs);

			zfree(tevs);

		}

		if (ret != ntevs)

			return ret < 0 ? ret : ntevs;

			ntevs = 0;

			ntevs = 0;

		/* Fall through */

		}

	}

	}





	debuginfo__delete(dinfo);



	if (ntevs == 0)	{	/* No error but failed to find probe point. */

	if (ntevs == 0)	{	/* No error but failed to find probe point. */

		pr_warning("Probe point '%s' not found.\n",

		pr_warning("Probe point '%s' not found.\n",

			   synthesize_perf_probe_point(&pev->point));

			   synthesize_perf_probe_point(&pev->point));

		return -ENOENT;

		return -ENOENT;

	}

	} else if (ntevs < 0) {

		/* Error path : ntevs < 0 */

		/* Error path : ntevs < 0 */

		pr_debug("An error occurred in debuginfo analysis (%d).\n", ntevs);

		pr_debug("An error occurred in debuginfo analysis (%d).\n", ntevs);

	if (ntevs < 0) {

		if (ntevs == -EBADF)

		if (ntevs == -EBADF)

			pr_warning("Warning: No dwarf info found in the vmlinux - "

			pr_warning("Warning: No dwarf info found in the vmlinux - "

				"please rebuild kernel with CONFIG_DEBUG_INFO=y.\n");

				"please rebuild kernel with CONFIG_DEBUG_INFO=y.\n");

tools/perf/util/probe-finder.c

+5 −2
Original line number Original line Diff line number Diff line
@@ -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 */

/* 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;

	int n, i;

	Elf32_Word shndx;

	Elf32_Word shndx;
@@ -1530,6 +1531,8 @@ static int debuginfo__get_text_offset(struct debuginfo *dbg, Dwarf_Addr *offs) 
			if (!shdr)

			if (!shdr)

				return -ENOENT;

				return -ENOENT;

			*offs = shdr->sh_addr;

			*offs = shdr->sh_addr;

			if (adjust_offset)

				*offs -= shdr->sh_offset;

		}

		}

	}

	}

	return 0;

	return 0;
@@ -1545,7 +1548,7 @@ int debuginfo__find_probe_point(struct debuginfo *dbg, unsigned long addr, 
	int baseline = 0, lineno = 0, ret = 0;

	int baseline = 0, lineno = 0, ret = 0;





	/* We always need to relocate the address for aranges */

	/* We always need to relocate the address for aranges */

	if (debuginfo__get_text_offset(dbg, &baseaddr) == 0)

	if (debuginfo__get_text_offset(dbg, &baseaddr, false) == 0)

		addr += baseaddr;

		addr += baseaddr;

	/* Find cu die */

	/* Find cu die */

	if (!dwarf_addrdie(dbg->dbg, (Dwarf_Addr)addr, &cudie)) {

	if (!dwarf_addrdie(dbg->dbg, (Dwarf_Addr)addr, &cudie)) {

tools/perf/util/probe-finder.h

+3 −0
Original line number Original line Diff line number Diff line
@@ -46,6 +46,9 @@ int debuginfo__find_trace_events(struct debuginfo *dbg, 
int debuginfo__find_probe_point(struct debuginfo *dbg, unsigned long addr,

int debuginfo__find_probe_point(struct debuginfo *dbg, unsigned long addr,

				struct perf_probe_point *ppt);

				struct perf_probe_point *ppt);





int debuginfo__get_text_offset(struct debuginfo *dbg, Dwarf_Addr *offs,

			       bool adjust_offset);



/* Find a line range */

/* Find a line range */

int debuginfo__find_line_range(struct debuginfo *dbg, struct line_range *lr);

int debuginfo__find_line_range(struct debuginfo *dbg, struct line_range *lr);

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