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From: "Masami Hiramatsu (Google)" <mhiramat@kernel.org>
To: LKML <linux-kernel@vger.kernel.org>
Cc: Linux Trace Kernel <linux-trace-kernel@vger.kernel.org>,
	Masami Hiramatsu <mhiramat@kernel.org>,
	Steven Rostedt <rostedt@goodmis.org>,
	Jiri Olsa <jolsa@kernel.org>
Subject: [PATCH v2] tracing/fprobe: Fix to check whether fprobe is registered correctly
Date: Wed, 26 Oct 2022 18:33:59 +0900	[thread overview]
Message-ID: <166677683946.1459107.15997653945538644683.stgit@devnote3> (raw)

From: Masami Hiramatsu (Google) <mhiramat@kernel.org>

Since commit ab51e15d535e ("fprobe: Introduce FPROBE_FL_KPROBE_SHARED flag
for fprobe") introduced fprobe_kprobe_handler() for fprobe::ops::func,
unregister_fprobe() fails to unregister the registered if user specifies
FPROBE_FL_KPROBE_SHARED flag.
Moreover, __register_ftrace_function() is possible to change the
ftrace_ops::func, thus we have to check fprobe::ops::saved_func instead.

To check it correctly, it should confirm the fprobe::ops::saved_func is
either fprobe_handler() or fprobe_kprobe_handler().

Fixes: cad9931f64dc ("fprobe: Add ftrace based probe APIs")
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
---
 kernel/trace/fprobe.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/kernel/trace/fprobe.c b/kernel/trace/fprobe.c
index 71614b2a67ff..e8143e368074 100644
--- a/kernel/trace/fprobe.c
+++ b/kernel/trace/fprobe.c
@@ -303,7 +303,8 @@ int unregister_fprobe(struct fprobe *fp)
 {
 	int ret;
 
-	if (!fp || fp->ops.func != fprobe_handler)
+	if (!fp || (fp->ops.saved_func != fprobe_handler &&
+		    fp->ops.saved_func != fprobe_kprobe_handler))
 		return -EINVAL;
 
 	/*


                 reply	other threads:[~2022-10-26  9:34 UTC|newest]

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