Re: [PATCH] ftrace: Fix regression with module command in stack_trace_filter
From: Steven Rostedt <rostedt@goodmis.org>
Date: 2024-11-20 14:51:51
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On Wed, 20 Nov 2024 13:27:49 +0800 guoweikang [off-list ref] 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
quoted hunk ↗ jump to hunk
Signed-off-by: guoweikang <redacted> --- 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)