From 6c502584438bda63fc1a67606854fb0b300465cd Mon Sep 17 00:00:00 2001 From: Jiri Olsa Date: Mon, 4 Jul 2016 14:16:23 +0200 Subject: [PATCH] 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: Jiri Olsa Cc: David Ahern Cc: He Kuang Cc: Namhyung Kim Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/1467634583-29147-5-git-send-email-jolsa@kernel.org Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/map.c | 9 ++++++++- tools/perf/util/map.h | 2 +- tools/perf/util/thread.c | 37 +++++++++++++++++++++++++++++++++++-- 3 files changed, 44 insertions(+), 4 deletions(-) diff --git a/tools/perf/util/map.c b/tools/perf/util/map.c index b19bcd3b7128..b39b12a1208d 100644 --- a/tools/perf/util/map.c +++ b/tools/perf/util/map.c @@ -15,6 +15,7 @@ #include "debug.h" #include "machine.h" #include +#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); } diff --git a/tools/perf/util/map.h b/tools/perf/util/map.h index 7309d64ce39e..d83396ceecba 100644 --- a/tools/perf/util/map.h +++ b/tools/perf/util/map.h @@ -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); diff --git a/tools/perf/util/thread.c b/tools/perf/util/thread.c index 2439b122a4e4..8b10a55410a2 100644 --- a/tools/perf/util/thread.c +++ b/tools/perf/util/thread.c @@ -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; -- 2.20.1