Merge tag 'trace-v6.16-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

2013e8c2 · Linus Torvalds <[email protected]> · 2025-07-20 13:03:31 -07:00

Pull tracing fixes from Steven Rostedt:

 - Fix timerlat with use of FORTIFY_SOURCE

   FORTIFY_SOURCE was added to the stack tracer where it compares the
   entry->caller array to having entry->size elements.

   timerlat has the following:

      memcpy(&entry->caller, fstack->calls, size);
      entry->size = size;

   Which triggers FORTIFY_SOURCE as the caller is populated before the
   entry->size is initialized.

   Swap the order to satisfy FORTIFY_SOURCE logic.

 - Add down_write(trace_event_sem) when adding trace events in modules

   Trace events being added to the ftrace_events array are protected by
   the trace_event_sem semaphore. But when loading modules that have
   trace events, the addition of the events are not protected by the
   semaphore and loading two modules that have events at the same time
   can corrupt the list.

   Also add a lockdep_assert_held(trace_event_sem) to
   _trace_add_event_dirs() to confirm it is held when iterating the
   list.

* tag 'trace-v6.16-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  tracing: Add down_write(trace_event_sem) when adding trace event
  tracing/osnoise: Fix crash in timerlat_dump_stack()

Commit: 2013e8c2e6fd3a4bdf4ccc658ad20a4469360eff
Parents: c10ee5cc · b5e8acc1

Merge commit. Changes below are compared with the first parent: c10ee5cc.

Changes

2 files changed · +6 −1

File	Status	Add	Del	Content
kernel/trace/trace_events.c	modified	+5	−0	View file
kernel/trace/trace_osnoise.c	modified	+1	−1	View file

kernel/trace/trace_events.c

View file

diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 1205312..d01e5c9 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -3136,7 +3136,10 @@ __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
@@ -3750,6 +3753,8 @@ __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)

kernel/trace/trace_osnoise.c

View file

diff --git a/kernel/trace/trace_osnoise.c b/kernel/trace/trace_osnoise.c
index 6819b93..fd259da 100644
--- a/kernel/trace/trace_osnoise.c
+++ b/kernel/trace/trace_osnoise.c
@@ -637,8 +637,8 @@ __timerlat_dump_stack(struct trace_buffer *buffer, struct trace_stack *fstack, u
 
 	entry = ring_buffer_event_data(event);
 
-	memcpy(&entry->caller, fstack->calls, size);
 	entry->size = fstack->nr_entries;
+	memcpy(&entry->caller, fstack->calls, size);
 
 	trace_buffer_unlock_commit_nostack(buffer, event);
 }