Linus,

tracing fix for 6.16:

- Do not free "head" variable in filter_free_subsystem_filters()

  The first error path jumps to "free_now" label but first frees the newly
  allocated "head" variable. But the "free_now" code checks this variable,
  and if it is not NULL, it will iterate the list. As this list variable
  was already initialized, the "free_now" code will not do anything as it
  is empty. But freeing it will cause a UAF bug. The error path should
  simply jump to the "free_now" label and leave the "head" variable alone.


Please pull the latest trace-v6.16-rc1 tree, which can be found at:


  git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace.git
trace-v6.16-rc1

Tag SHA1: 3dec58ebef0af8431ecffae2b1814a11b86dbde1
Head SHA1: 8a157d8a00e815cab4432653cb50c9cedbbb4931


Steven Rostedt (1):
      tracing: Do not free "head" on error path of filter_free_subsystem_filters()

----
 kernel/trace/trace_events_filter.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)
---------------------------
diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c
index ea8b364b6818..08141f105c95 100644
--- a/kernel/trace/trace_events_filter.c
+++ b/kernel/trace/trace_events_filter.c
@@ -1437,10 +1437,8 @@ static void filter_free_subsystem_filters(struct trace_subsystem_dir *dir,
 	INIT_LIST_HEAD(&head->list);
 
 	item = kmalloc(sizeof(*item), GFP_KERNEL);
-	if (!item) {
-		kfree(head);
+	if (!item)
 		goto free_now;
-	}
 
 	item->filter = filter;
 	list_add_tail(&item->list, &head->list);

On Fri, 13 Jun 2025 at 08:50, Steven Rostedt <rostedt@goodmis.org> wrote:
>
>   git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace.git
> trace-v6.16-rc1
>
> Tag SHA1: 3dec58ebef0af8431ecffae2b1814a11b86dbde1
> Head SHA1: 8a157d8a00e815cab4432653cb50c9cedbbb4931

I see the HEAD in the 'trace/fixes' branch, but no tags anywhere.
Forgot to push?

               Linus

On Fri, 13 Jun 2025 10:05:17 -0700
Linus Torvalds <torvalds@linux-foundation.org> wrote:


> I see the HEAD in the 'trace/fixes' branch, but no tags anywhere.
> Forgot to push?

Yep. Sorry about that.

I just pushed it now.

-- Steve