* [PATCH] ftrace: Fix regression with module command in stack_trace_filter
@ 2024-11-20 5:27 guoweikang
2024-11-20 14:52 ` Steven Rostedt
0 siblings, 1 reply; 2+ messages in thread
From: guoweikang @ 2024-11-20 5:27 UTC (permalink / raw)
To: rostedt, Masami Hiramatsu, Mark Rutland, Mathieu Desnoyers
Cc: guoweikang, linux-kernel, linux-trace-kernel
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.
Signed-off-by: guoweikang <guoweikang.kernel@gmail.com>
---
kernel/trace/ftrace.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 71e53eaba8bc..9b17efb1a87d 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -5093,6 +5093,9 @@ 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)
--
2.25.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] ftrace: Fix regression with module command in stack_trace_filter
2024-11-20 5:27 [PATCH] ftrace: Fix regression with module command in stack_trace_filter guoweikang
@ 2024-11-20 14:52 ` Steven Rostedt
0 siblings, 0 replies; 2+ messages in thread
From: Steven Rostedt @ 2024-11-20 14:52 UTC (permalink / raw)
To: guoweikang
Cc: Masami Hiramatsu, Mark Rutland, Mathieu Desnoyers, linux-kernel,
linux-trace-kernel
On Wed, 20 Nov 2024 13:27:49 +0800
guoweikang <guoweikang.kernel@gmail.com> wrote:
> 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.
Ouch!
Thanks, I'll also mark this as stable.
-- Steve
>
> Signed-off-by: guoweikang <guoweikang.kernel@gmail.com>
> ---
> kernel/trace/ftrace.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
> index 71e53eaba8bc..9b17efb1a87d 100644
> --- a/kernel/trace/ftrace.c
> +++ b/kernel/trace/ftrace.c
> @@ -5093,6 +5093,9 @@ 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)
^ permalink raw reply [flat|nested] 2+ messages in thread
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2024-11-20 14:52 ` Steven Rostedt
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