6.15-stable review patch. If anyone has any objections, please let me know.
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From: Steven Rostedt rostedt@goodmis.org
commit 8a157d8a00e815cab4432653cb50c9cedbbb4931 upstream.
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.
Cc: Masami Hiramatsu mhiramat@kernel.org Cc: Mathieu Desnoyers mathieu.desnoyers@efficios.com Link: https://lore.kernel.org/20250610093348.33c5643a@gandalf.local.home Fixes: a9d0aab5eb33 ("tracing: Fix regression of filter waiting a long time on RCU synchronization") Reported-by: kernel test robot lkp@intel.com Reported-by: Dan Carpenter dan.carpenter@linaro.org Closes: https://lore.kernel.org/r/202506070424.lCiNreTI-lkp@intel.com/ Signed-off-by: Steven Rostedt (Google) rostedt@goodmis.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- kernel/trace/trace_events_filter.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-)
--- a/kernel/trace/trace_events_filter.c +++ b/kernel/trace/trace_events_filter.c @@ -1435,10 +1435,8 @@ static void filter_free_subsystem_filter 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);