From abd828688407eb86044f1bc9e5133c55d7597596 Mon Sep 17 00:00:00 2001 From: Arnaldo Carvalho de Melo Date: Fri, 11 Dec 2015 19:11:23 -0300 Subject: 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 Cc: Adrian Hunter Cc: David Ahern Cc: Jiri Olsa Cc: Namhyung Kim Cc: Wang Nan Link: http://lkml.kernel.org/n/tip-4b9mkuk66to4ecckpmpvqx6s@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/thread.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) (limited to 'tools/perf/util/thread.c') 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); } -- cgit v1.2.3