[PATCH bpf] bpf: Cleanup ftrace hash in bpf_trampoline_put

From: Jiri Olsa <jolsa@kernel.org>
To: Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Andrii Nakryiko <andrii@kernel.org>
Cc: bpf@vger.kernel.org, Martin KaFai Lau <kafai@fb.com>,
	Song Liu <songliubraving@fb.com>, Yonghong Song <yhs@fb.com>,
	John Fastabend <john.fastabend@gmail.com>,
	KP Singh <kpsingh@chromium.org>,
	Stanislav Fomichev <sdf@google.com>, Hao Luo <haoluo@google.com>,
	Steven Rostedt <rostedt@goodmis.org>
Subject: [PATCH bpf] bpf: Cleanup ftrace hash in bpf_trampoline_put
Date: Tue,  2 Aug 2022 15:56:51 +0200	[thread overview]
Message-ID: <20220802135651.1794015-1-jolsa@kernel.org> (raw)

We need to release possible hash from trampoline fops object
before removing it, otherwise we leak it.

Fixes: 00963a2e75a8 ("bpf: Support bpf_trampoline on functions with IPMODIFY (e.g. livepatch)")
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
---
 kernel/bpf/trampoline.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/kernel/bpf/trampoline.c b/kernel/bpf/trampoline.c
index 0f532e6a717f..ff87e38af8a7 100644
--- a/kernel/bpf/trampoline.c
+++ b/kernel/bpf/trampoline.c
@@ -841,7 +841,10 @@ void bpf_trampoline_put(struct bpf_trampoline *tr)
 	 * multiple rcu callbacks.
 	 */
 	hlist_del(&tr->hlist);
-	kfree(tr->fops);
+	if (tr->fops) {
+		ftrace_free_filter(tr->fops);
+		kfree(tr->fops);
+	}
 	kfree(tr);
 out:
 	mutex_unlock(&trampoline_mutex);
-- 
2.37.1

