From: Steven Rostedt <rostedt@goodmis.org> stable inclusion from stable-6.6.102 commit 6bc94f20a4c304997288f9a45278c9d0c06987d3 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/ICTB6I CVE: CVE-2025-38539 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- commit b5e8acc14dcb314a9b61ff19dcd9fdd0d88f70df upstream. When a module is loaded, it adds trace events defined by the module. It may also need to modify the modules trace printk formats to replace enum names with their values. If two modules are loaded at the same time, the adding of the event to the ftrace_events list can corrupt the walking of the list in the code that is modifying the printk format strings and crash the kernel. The addition of the event should take the trace_event_sem for write while it adds the new event. Also add a lockdep_assert_held() on that semaphore in __trace_add_event_dirs() as it iterates the list. Cc: stable@vger.kernel.org Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Link: https://lore.kernel.org/20250718223158.799bfc0c@batman.local.home Reported-by: Fusheng Huang(黄富生) <Fusheng.Huang@luxshare-ict.com> Closes: https://lore.kernel.org/all/20250717105007.46ccd18f@batman.local.home/ Fixes: 110bf2b764eb6 ("tracing: add protection around module events unload") Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Tengda Wu <wutengda2@huawei.com> --- kernel/trace/trace_events.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c index f2e07d470784..90534dd96adb 100644 --- a/kernel/trace/trace_events.c +++ b/kernel/trace/trace_events.c @@ -2843,7 +2843,10 @@ __register_event(struct trace_event_call *call, struct module *mod) if (ret < 0) return ret; + down_write(&trace_event_sem); list_add(&call->list, &ftrace_events); + up_write(&trace_event_sem); + if (call->flags & TRACE_EVENT_FL_DYNAMIC) atomic_set(&call->refcnt, 0); else @@ -3379,6 +3382,8 @@ __trace_add_event_dirs(struct trace_array *tr) struct trace_event_call *call; int ret; + lockdep_assert_held(&trace_event_sem); + list_for_each_entry(call, &ftrace_events, list) { ret = __trace_add_new_event(call, tr); if (ret < 0) -- 2.34.1