[GIT PULL] tracing: Fixes for v6.16

From: Steven Rostedt
Date: Fri Jun 13 2025 - 11:51:52 EST




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);