[PATCH v1 4/4] perf thread: Fixes to thread__new

From: Ian Rogers
Date: Tue May 07 2024 - 23:54:03 EST


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@xxxxxxxxxx>
---
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