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perf thread: Fix reference count initial state

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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>
This commit is contained in:
Arnaldo Carvalho de Melo
2015-12-11 19:11:23 -03:00
parent b6847d2c2a
commit abd8286884
3 changed files with 22 additions and 11 deletions
Download Patch File Download Diff File Expand all files Collapse all files

19
tools/perf/util/machine.c
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@@ -352,13 +352,18 @@ static void machine__update_thread_pid(struct machine *machine,
}
th->mg = map_groups__get(leader->mg);
out_put:
thread__put(leader);
return;
out_err:
pr_err("Failed to join map groups for %d:%d\n", th->pid_, th->tid);
goto out_put;
}
/*
* Caller must eventually drop thread->refcnt returned with a successfull
* lookup/new thread inserted.
*/
static struct thread *____machine__findnew_thread(struct machine *machine,
pid_t pid, pid_t tid,
bool create)
@@ -376,7 +381,7 @@ static struct thread *____machine__findnew_thread(struct machine *machine,
if (th != NULL) {
if (th->tid == tid) {
machine__update_thread_pid(machine, th, pid);
return th;
return thread__get(th);
}
machine->last_match = NULL;
@@ -389,7 +394,7 @@ static struct thread *____machine__findnew_thread(struct machine *machine,
if (th->tid == tid) {
machine->last_match = th;
machine__update_thread_pid(machine, th, pid);
return th;
return thread__get(th);
}
if (tid < th->tid)
@@ -417,7 +422,7 @@ static struct thread *____machine__findnew_thread(struct machine *machine,
if (thread__init_map_groups(th, machine)) {
rb_erase_init(&th->rb_node, &machine->threads);
RB_CLEAR_NODE(&th->rb_node);
thread__delete(th);
thread__put(th);
return NULL;
}
/*
@@ -441,7 +446,7 @@ struct thread *machine__findnew_thread(struct machine *machine, pid_t pid,
struct thread *th;
pthread_rwlock_wrlock(&machine->threads_lock);
th = thread__get(__machine__findnew_thread(machine, pid, tid));
th = __machine__findnew_thread(machine, pid, tid);
pthread_rwlock_unlock(&machine->threads_lock);
return th;
}
@@ -451,7 +456,7 @@ struct thread *machine__find_thread(struct machine *machine, pid_t pid,
{
struct thread *th;
pthread_rwlock_rdlock(&machine->threads_lock);
th = thread__get(____machine__findnew_thread(machine, pid, tid, false));
th = ____machine__findnew_thread(machine, pid, tid, false);
pthread_rwlock_unlock(&machine->threads_lock);
return th;
}