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authorArnaldo Carvalho de Melo <acme@redhat.com>2015-12-12 01:11:23 +0300
committerArnaldo Carvalho de Melo <acme@redhat.com>2015-12-14 18:08:55 +0300
commitabd828688407eb86044f1bc9e5133c55d7597596 (patch)
treeb42146c0c9ffa8dc7cd3643af4e021b5a4f4d1b8 /tools/perf/util/thread.c
parentb6847d2c2a50e96680e233ce4b2784981b6f309e (diff)
downloadlinux-abd828688407eb86044f1bc9e5133c55d7597596.tar.xz
perf thread: Fix reference count initial state
We should always return from thread__new(), the constructor, with the object with a reference count of one, so that: struct thread *thread = thread__new(); thread__put(thread); Will call thread__delete(). If any reference is made to that 'thread' variable, it better use thread__get(thread) to hold a reference. We were returning with thread->refcnt set to zero, fix it and some cases where thread__delete() was being called, which were not a problem because just one reference was being used, now that we set it to 1, use thread__put() instead. Reported-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: David Ahern <dsahern@gmail.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Wang Nan <wangnan0@huawei.com> Link: http://lkml.kernel.org/n/tip-4b9mkuk66to4ecckpmpvqx6s@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'tools/perf/util/thread.c')
-rw-r--r--tools/perf/util/thread.c10
1 files changed, 8 insertions, 2 deletions
diff --git a/tools/perf/util/thread.c b/tools/perf/util/thread.c
index 0a9ae8014729..dfd00c6dad6e 100644
--- a/tools/perf/util/thread.c
+++ b/tools/perf/util/thread.c
@@ -19,8 +19,10 @@ int thread__init_map_groups(struct thread *thread, struct machine *machine)
thread->mg = map_groups__new(machine);
} else {
leader = __machine__findnew_thread(machine, pid, pid);
- if (leader)
+ if (leader) {
thread->mg = map_groups__get(leader->mg);
+ thread__put(leader);
+ }
}
return thread->mg ? 0 : -1;
@@ -53,7 +55,7 @@ struct thread *thread__new(pid_t pid, pid_t tid)
goto err_thread;
list_add(&comm->list, &thread->comm_list);
- atomic_set(&thread->refcnt, 0);
+ atomic_set(&thread->refcnt, 1);
RB_CLEAR_NODE(&thread->rb_node);
}
@@ -95,6 +97,10 @@ struct thread *thread__get(struct thread *thread)
void thread__put(struct thread *thread)
{
if (thread && atomic_dec_and_test(&thread->refcnt)) {
+ /*
+ * Remove it from the dead_threads list, as last reference
+ * is gone.
+ */
list_del_init(&thread->node);
thread__delete(thread);
}