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Commit 419e8738 authored by Masami Hiramatsu's avatar Masami Hiramatsu Committed by Arnaldo Carvalho de Melo
Browse files

perf probe: Show the error reason comes from invalid DSO 



Show the reason of error when dso__load* fails. This shows when user
gives wrong kernel image or wrong path.

Without this, perf probe shows an obscure message:

  ----
  $ perf probe -k ~/kbin/linux-3.x86_64/vmlinux -L vfs_read
  Failed to find path of kernel module.
    Error: Failed to show lines.
  ----

With this, perf shows appropriate error message:

  ----
  $ perf probe -k ~/kbin/linux-3.x86_64/vmlinux -L vfs_read
  Failed to find the path for kernel: Mismatching build id
    Error: Failed to show lines.
  ----

And:

  ----
  $ perf probe -k /non-exist/kernel/vmlinux -L vfs_read
  Failed to find the path for kernel: No such file or directory
    Error: Failed to show lines.
  ----

Signed-off-by: default avatarMasami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Tested-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Richard Weinberger <richard@nod.at>
Link: http://lkml.kernel.org/r/20150527083718.23880.84100.stgit@localhost.localdomain


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent 9b5d1c29

tools/perf/util/probe-event.c

+24 −23
Original line number Diff line number Diff line
@@ -200,11 +200,12 @@ static void put_target_map(struct map *map, bool user) 
}





static struct dso *kernel_get_module_dso(const char *module)

static int kernel_get_module_dso(const char *module, struct dso **pdso)

{

	struct dso *dso;

	struct map *map;

	const char *vmlinux_name;

	int ret = 0;



	if (module) {

		list_for_each_entry(dso, &host_machine->kernel_dsos.head,
@@ -214,30 +215,21 @@ static struct dso *kernel_get_module_dso(const char *module) 
				goto found;

		}

		pr_debug("Failed to find module %s.\n", module);

		return NULL;

		return -ENOENT;

	}



	map = host_machine->vmlinux_maps[MAP__FUNCTION];

	dso = map->dso;



	vmlinux_name = symbol_conf.vmlinux_name;

	if (vmlinux_name) {

		if (dso__load_vmlinux(dso, map, vmlinux_name, false, NULL) <= 0)

			return NULL;

	} else {

		if (dso__load_vmlinux_path(dso, map, NULL) <= 0) {

			pr_debug("Failed to load kernel map.\n");

			return NULL;

		}

	}

	dso->load_errno = 0;

	if (vmlinux_name)

		ret = dso__load_vmlinux(dso, map, vmlinux_name, false, NULL);

	else

		ret = dso__load_vmlinux_path(dso, map, NULL);

found:

	return dso;

}



const char *kernel_get_module_path(const char *module)

{

	struct dso *dso = kernel_get_module_dso(module);

	return (dso) ? dso->long_name : NULL;

	*pdso = dso;

	return ret;

}



static int convert_exec_to_group(const char *exec, char **result)
@@ -389,16 +381,25 @@ static int get_alternative_line_range(struct debuginfo *dinfo, 
static struct debuginfo *open_debuginfo(const char *module, bool silent)

{

	const char *path = module;

	struct debuginfo *ret;

	char reason[STRERR_BUFSIZE];

	struct debuginfo *ret = NULL;

	struct dso *dso = NULL;

	int err;



	if (!module || !strchr(module, '/')) {

		path = kernel_get_module_path(module);

		if (!path) {

		err = kernel_get_module_dso(module, &dso);

		if (err < 0) {

			if (!dso || dso->load_errno == 0) {

				if (!strerror_r(-err, reason, STRERR_BUFSIZE))

					strcpy(reason, "(unknown)");

			} else

				dso__strerror_load(dso, reason, STRERR_BUFSIZE);

			if (!silent)

				pr_err("Failed to find path of %s module.\n",

				       module ?: "kernel");

				pr_err("Failed to find the path for %s: %s\n",

					module ?: "kernel", reason);

			return NULL;

		}

		path = dso->long_name;

	}

	ret = debuginfo__new(path);

	if (!ret && !silent) {

tools/perf/util/probe-event.h

+0 −3
Original line number Diff line number Diff line
@@ -131,9 +131,6 @@ extern void line_range__clear(struct line_range *lr); 
/* Initialize line range */

extern int line_range__init(struct line_range *lr);



/* Internal use: Return kernel/module path */

extern const char *kernel_get_module_path(const char *module);



extern int add_perf_probe_events(struct perf_probe_event *pevs, int npevs);

extern int del_perf_probe_events(struct strfilter *filter);

extern int show_perf_probe_events(struct strfilter *filter);