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From: "Masami Hiramatsu (Google)" <mhiramat@kernel.org>
To: Steven Rostedt <rostedt@goodmis.org>,
	Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
	linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org
Subject: [PATCH] fprobe: Fix module reference count leak on error in register_fprobe()
Date: Wed, 29 Jul 2026 08:27:33 +0900	[thread overview]
Message-ID: <178528125360.101985.4144133640239273153.stgit@devnote2> (raw)

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

In register_fprobe(), get_ips_from_filter() resolves target function
addresses and increments module reference counts via try_module_get() for
symbols in kernel modules. If get_ips_from_filter() fails on the second
pass and returns an error, register_fprobe() returned directly without
releasing module references acquired up to that point.

Fix this by ensuring the cleanup loop executing module_put() runs even when
get_ips_from_filter() returns a negative error.

Fixes: d24fa977eec5 ("tracing: fprobe: Fix to lock module while registering fprobe")
Assisted-by: Antigravity:gemini-3.6-flash
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
---
 kernel/trace/fprobe.c |    6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/kernel/trace/fprobe.c b/kernel/trace/fprobe.c
index f215990b9061..f681015413b8 100644
--- a/kernel/trace/fprobe.c
+++ b/kernel/trace/fprobe.c
@@ -961,10 +961,8 @@ int register_fprobe(struct fprobe *fp, const char *filter, const char *notfilter
 		return -ENOMEM;
 
 	ret = get_ips_from_filter(filter, notfilter, addrs, mods, num);
-	if (ret < 0)
-		return ret;
-
-	ret = register_fprobe_ips(fp, addrs, ret);
+	if (ret >= 0)
+		ret = register_fprobe_ips(fp, addrs, ret);
 
 	for (int i = 0; i < num; i++) {
 		if (mods[i])


                 reply	other threads:[~2026-07-28 23:27 UTC|newest]

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