Received-SPF: pass (google.com: domain of linux-kernel+bounces-172669-linux.lists.archive=gmail.com@vger.kernel.org designates 139.178.88.99 as permitted sender) client-ip=139.178.88.99;
Date: Tue,  7 May 2024 20:53:01 -0700
In-Reply-To: <20240508035301.1554434-1-irogers@google.com>
Message-Id: <20240508035301.1554434-5-irogers@google.com>
Precedence: bulk
Mime-Version: 1.0
References: <20240508035301.1554434-1-irogers@google.com>
Subject: [PATCH v1 4/4] perf thread: Fixes to thread__new
From: Ian Rogers <irogers@google.com>
To: Peter Zijlstra <peterz@infradead.org>, Ingo Molnar <mingo@redhat.com>, 
	Arnaldo Carvalho de Melo <acme@kernel.org>, Namhyung Kim <namhyung@kernel.org>, 
	Mark Rutland <mark.rutland@arm.com>, 
	Alexander Shishkin <alexander.shishkin@linux.intel.com>, Jiri Olsa <jolsa@kernel.org>, 
	Ian Rogers <irogers@google.com>, Adrian Hunter <adrian.hunter@intel.com>, 
	Kan Liang <kan.liang@linux.intel.com>, James Clark <james.clark@arm.com>, 
	Leo Yan <leo.yan@linux.dev>, linux-perf-users@vger.kernel.org, 
	linux-kernel@vger.kernel.org
Content-Type: text/plain; charset="UTF-8"

Freeing the thread on failure won't work with reference count
checking, use thread__delete. Don't allocate the comm_str, use a stack
allocation instead.

Fixes: f6005cafebab ("perf thread: Add reference count checking")
Signed-off-by: Ian Rogers <irogers@google.com>
---
 tools/perf/util/thread.c | 14 +++++---------
 1 file changed, 5 insertions(+), 9 deletions(-)

diff --git a/tools/perf/util/thread.c b/tools/perf/util/thread.c
index 0a473112f881..87c59aa9fe38 100644
--- a/tools/perf/util/thread.c
+++ b/tools/perf/util/thread.c
@@ -39,12 +39,13 @@ int thread__init_maps(struct thread *thread, struct machine *machine)
 
 struct thread *thread__new(pid_t pid, pid_t tid)
 {
-	char *comm_str;
-	struct comm *comm;
 	RC_STRUCT(thread) *_thread = zalloc(sizeof(*_thread));
 	struct thread *thread;
 
 	if (ADD_RC_CHK(thread, _thread) != NULL) {
+		struct comm *comm;
+		char comm_str[32];
+
 		thread__set_pid(thread, pid);
 		thread__set_tid(thread, tid);
 		thread__set_ppid(thread, -1);
@@ -56,13 +57,8 @@ struct thread *thread__new(pid_t pid, pid_t tid)
 		init_rwsem(thread__namespaces_lock(thread));
 		init_rwsem(thread__comm_lock(thread));
 
-		comm_str = malloc(32);
-		if (!comm_str)
-			goto err_thread;
-
-		snprintf(comm_str, 32, ":%d", tid);
+		snprintf(comm_str, sizeof(comm_str), ":%d", tid);
 		comm = comm__new(comm_str, 0, false);
-		free(comm_str);
 		if (!comm)
 			goto err_thread;
 
@@ -76,7 +72,7 @@ struct thread *thread__new(pid_t pid, pid_t tid)
 	return thread;
 
 err_thread:
-	free(thread);
+	thread__delete(thread);
 	return NULL;
 }
 
-- 
2.45.0.rc1.225.g2a3ae87e7f-goog