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perf unwind: Call unwind__prepare_access for forked thread

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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 <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: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Jiri Olsa
2016-07-04 14:16:23 +02:00
committed by Arnaldo Carvalho de Melo
parent a2873325ff
commit 6c50258443
3 changed files with 44 additions and 4 deletions
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37
tools/perf/util/thread.c
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@@ -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;