5.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: guoweikang <guoweikang.kernel@xxxxxxxxx>
commit 45af52e7d3b8560f21d139b3759735eead8b1653 upstream.
When executing the following command:
# echo "write*:mod:ext3" > /sys/kernel/tracing/stack_trace_filter
The current mod command causes a null pointer dereference. While commit
0f17976568b3f ("ftrace: Fix regression with module command in stack_trace_filter")
has addressed part of the issue, it left a corner case unhandled, which still
results in a kernel crash.
Cc: stable@xxxxxxxxxxxxxxx
Cc: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
Cc: Mark Rutland <mark.rutland@xxxxxxx>
Cc: Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxxxx>
Link: https://lore.kernel.org/20241120052750.275463-1-guoweikang.kernel@xxxxxxxxx
Fixes: 04ec7bb642b77 ("tracing: Have the trace_array hold the list of registered func probes");
Signed-off-by: guoweikang <guoweikang.kernel@xxxxxxxxx>
Signed-off-by: Steven Rostedt (Google) <rostedt@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
kernel/trace/ftrace.c | 3 +++
1 file changed, 3 insertions(+)
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -4132,6 +4132,9 @@ ftrace_mod_callback(struct trace_array *
char *func;
int ret;
+ if (!tr)
+ return -ENODEV;
+
/* match_records() modifies func, and we need the original */
func = kstrdup(func_orig, GFP_KERNEL);
if (!func)
