diff options
| author | Haotian Zhang <vulab@iscas.ac.cn> | 2026-08-26 09:50:34 +0800 |
|---|---|---|
| committer | Steven Rostedt <rostedt@goodmis.org> | 2026-08-26 15:49:15 -0400 |
| commit | d79fb758e7e2e7a181eab630c0545a56041c473d (patch) | |
| tree | c07a4e808ca95e8ec78dd9c5f40d4ac806ca27fd /samples | |
| parent | 1704aaaf5d22bc765c168402350d191e24e245bc (diff) | |
samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify
ftrace_direct_init() assigns kthread_run()'s return value to simple_tsk
without an IS_ERR() check. When kthread_run() fails it returns
ERR_PTR(-ENOMEM), but init still returns 0, so the module loads with
simple_tsk holding an error pointer. On unload, ftrace_direct_exit()
then passes that ERR_PTR to kthread_stop(), leading to a
null-pointer-dereference.
Check the return value of kthread_run() with IS_ERR(); on failure,
unregister the ftrace direct call and propagate the error code.
Link: https://patch.msgid.link/20260826015034.10755-1-vulab@iscas.ac.cn
Fixes: ae0cc3b7e7f5 ("ftrace/samples: Add a sample module that implements modify_ftrace_direct()")
Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Haotian Zhang <vulab@iscas.ac.cn>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Diffstat (limited to 'samples')
| -rw-r--r-- | samples/ftrace/ftrace-direct-modify.c | 12 |
1 files changed, 9 insertions, 3 deletions
diff --git a/samples/ftrace/ftrace-direct-modify.c b/samples/ftrace/ftrace-direct-modify.c index 1ba1927b548e..164d9dd6fd92 100644 --- a/samples/ftrace/ftrace-direct-modify.c +++ b/samples/ftrace/ftrace-direct-modify.c @@ -320,9 +320,15 @@ static int __init ftrace_direct_init(void) ftrace_set_filter_ip(&direct, (unsigned long) my_ip, 0, 0); ret = register_ftrace_direct(&direct, my_tramp); - if (!ret) - simple_tsk = kthread_run(simple_thread, NULL, "event-sample-fn"); - return ret; + if (ret) + return ret; + simple_tsk = kthread_run(simple_thread, NULL, "event-sample-fn"); + if (IS_ERR(simple_tsk)) { + unregister_ftrace_direct(&direct, my_tramp, true); + return PTR_ERR(simple_tsk); + } + + return 0; } static void __exit ftrace_direct_exit(void) |