Commit 6c502584 authored by Jiri Olsa's avatar Jiri Olsa Committed by Arnaldo Carvalho de Melo
Browse files

perf unwind: Call unwind__prepare_access for forked thread 



Currently we call unwind__prepare_access for map event.  In case we
report fork event the thread inherits its parent's maps and
unwind__prepare_access is never called for the thread.

This causes unwind__get_entries seeing uninitialized
unwind_libunwind_ops and thus returning no callchain.

Adding unwind__prepare_access calls for fork even processing.

Signed-off-by: default avatarJiri Olsa <jolsa@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: He Kuang <hekuang@huawei.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1467634583-29147-5-git-send-email-jolsa@kernel.org


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent a2873325

tools/perf/util/map.c

+8 −1
Original line number Diff line number Diff line
@@ -15,6 +15,7 @@ 
#include "debug.h"

#include "machine.h"

#include <linux/string.h>

#include "unwind.h"



static void __maps__insert(struct maps *maps, struct map *map);
@@ -744,9 +745,10 @@ int map_groups__fixup_overlappings(struct map_groups *mg, struct map *map, 
/*

 * XXX This should not really _copy_ te maps, but refcount them.

 */

int map_groups__clone(struct map_groups *mg,

int map_groups__clone(struct thread *thread,

		      struct map_groups *parent, enum map_type type)

{

	struct map_groups *mg = thread->mg;

	int err = -ENOMEM;

	struct map *map;

	struct maps *maps = &parent->maps[type];
@@ -757,6 +759,11 @@ int map_groups__clone(struct map_groups *mg, 
		struct map *new = map__clone(map);

		if (new == NULL)

			goto out_unlock;



		err = unwind__prepare_access(thread, new, NULL);

		if (err)

			goto out_unlock;



		map_groups__insert(mg, new);

		map__put(new);

	}

tools/perf/util/map.h

+1 −1
Original line number Diff line number Diff line
@@ -194,7 +194,7 @@ struct symbol *maps__find_symbol_by_name(struct maps *maps, const char *name, 
                                         struct map **mapp, symbol_filter_t filter);

void map_groups__init(struct map_groups *mg, struct machine *machine);

void map_groups__exit(struct map_groups *mg);

int map_groups__clone(struct map_groups *mg,

int map_groups__clone(struct thread *thread,

		      struct map_groups *parent, enum map_type type);

size_t map_groups__fprintf(struct map_groups *mg, FILE *fp);

tools/perf/util/thread.c

+35 −2
Original line number Diff line number Diff line
@@ -212,6 +212,39 @@ int thread__insert_map(struct thread *thread, struct map *map) 
	return 0;

}



static int __thread__prepare_access(struct thread *thread)

{

	bool initialized = false;

	int i, err = 0;



	for (i = 0; i < MAP__NR_TYPES; ++i) {

		struct maps *maps = &thread->mg->maps[i];

		struct map *map;



		pthread_rwlock_rdlock(&maps->lock);



		for (map = maps__first(maps); map; map = map__next(map)) {

			err = unwind__prepare_access(thread, map, &initialized);

			if (err || initialized)

				break;

		}



		pthread_rwlock_unlock(&maps->lock);

	}



	return err;

}



static int thread__prepare_access(struct thread *thread)

{

	int err = 0;



	if (symbol_conf.use_callchain)

		err = __thread__prepare_access(thread);



	return err;

}



static int thread__clone_map_groups(struct thread *thread,

				    struct thread *parent)

{
@@ -219,7 +252,7 @@ static int thread__clone_map_groups(struct thread *thread, 


	/* This is new thread, we share map groups for process. */

	if (thread->pid_ == parent->pid_)

		return 0;

		return thread__prepare_access(thread);



	if (thread->mg == parent->mg) {

		pr_debug("broken map groups on thread %d/%d parent %d/%d\n",
@@ -229,7 +262,7 @@ static int thread__clone_map_groups(struct thread *thread, 


	/* But this one is new process, copy maps. */

	for (i = 0; i < MAP__NR_TYPES; ++i)

		if (map_groups__clone(thread->mg, parent->mg, i) < 0)

		if (map_groups__clone(thread, parent->mg, i) < 0)

			return -ENOMEM;



	return 0;

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