| From 649bc7df3e5d7be6f7996a95084037dbf3cad1e5 Mon Sep 17 00:00:00 2001 |
| From: Hui Su <sh_def@163.com> |
| Date: Mon, 17 Aug 2026 20:06:44 +0800 |
| Subject: tracing: Fix crash passing ERR_PTR to kthread_stop() |
| |
| From: Hui Su <sh_def@163.com> |
| |
| commit 649bc7df3e5d7be6f7996a95084037dbf3cad1e5 upstream. |
| |
| event_test_stuff() calls kthread_run() and unconditionally passes the |
| returned task_struct pointer to kthread_stop(). kthread_run() returns an |
| error pointer such as ERR_PTR(-ENOMEM) when kthread creation fails, for |
| example under memory pressure during the boot-time event self-test. |
| kthread_stop() then dereferences the invalid pointer, crashing the kernel. |
| |
| Check the result of kthread_run() before passing it to kthread_stop(). Use |
| WARN_ON() so that a failure to create the self-test thread does not go |
| unnoticed, matching the ring-buffer self-test fix in commit |
| 91542863abad ("ring-buffer: Fix crash passing ERR_PTR to kthread_stop()"). |
| |
| Cc: stable@vger.kernel.org |
| Fixes: e6187007d6c3 ("tracing/events: add startup tests for events") |
| Link: https://patch.msgid.link/20260817120642.668375-3-sh_def@163.com |
| Signed-off-by: Hui Su <sh_def@163.com> |
| Signed-off-by: Steven Rostedt <rostedt@goodmis.org> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| --- |
| kernel/trace/trace_events.c | 2 ++ |
| 1 file changed, 2 insertions(+) |
| |
| --- a/kernel/trace/trace_events.c |
| +++ b/kernel/trace/trace_events.c |
| @@ -4350,6 +4350,8 @@ static __init void event_test_stuff(void |
| struct task_struct *test_thread; |
| |
| test_thread = kthread_run(event_test_thread, NULL, "test-events"); |
| + if (WARN_ON(IS_ERR(test_thread))) |
| + return; |
| msleep(1); |
| kthread_stop(test_thread); |
| } |
