From: Steven Rostedt <rost...@goodmis.org>
The variable "head" is allocated and initialized as a list before
allocating the first "item" for the list. If the allocation of "item"
fails, it frees "head" and then jumps to the label "free_now" which will
process head and free it.
This will cause a UAF of "head", and it doesn't need to free it before
jumping to the "free_now" label as that code will free it.
Fixes: a9d0aab5eb33 ("tracing: Fix regression of filter waiting a long time on
RCU synchronization")
Reported-by: kernel test robot <l...@intel.com>
Reported-by: Dan Carpenter <dan.carpen...@linaro.org>
Closes: https://lore.kernel.org/r/202506070424.lcinreti-...@intel.com/
Signed-off-by: Steven Rostedt (Google) <rost...@goodmis.org>
---
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);
--
2.47.2
