From 19cacabdd5a8487ae566cbecb4d03bcb038a067e Mon Sep 17 00:00:00 2001
From: guoweikang <guoweikang.kernel@gmail.com>
Date: Wed, 20 Nov 2024 13:27:49 +0800
Subject: [PATCH] ftrace: Fix regression with module command in
stack_trace_filter
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@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://lore.kernel.org/20241120052750.275463-1-guoweikang.kernel@gmail.com
Fixes: 04ec7bb642b77 ("tracing: Have the trace_array hold the list of registered func probes");
Signed-off-by: guoweikang <guoweikang.kernel@gmail.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
kernel/trace/ftrace.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index d2dd71d04b8ac..3dd3b97d8049a 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -5080,6 +5080,9 @@ ftrace_mod_callback(struct trace_array *tr, struct ftrace_hash *hash,
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)
--
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