From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-182.mta0.migadu.com (out-182.mta0.migadu.com [91.218.175.182]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C9C122E9EBA for ; Thu, 24 Jul 2025 15:15:28 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.182 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753370131; cv=none; b=IqgqYZrimWMOr2prVjUgNA7Yen9o4TPQUrTeddu7B4xIENWWgvQoEGgIR/tt/J7kPzA+PIXZBNV+/JerK6aZSB3JI/L9mhkSCBnbW03F0ghBhQuDAvlCeJRSsjavNhR0aKzrS8K2Nd1ctPmk+Ty6+ngXbA3rhbTEcBAWtsE5gu8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753370131; c=relaxed/simple; bh=Rp6QB38jGHbwBhBe9EF3FxRJm3xchbnZjDcQFcC5nRg=; h=From:To:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=TSIUsgFtxK4lxLJ8jUX3JU/r2dgkSqKYZGLPBEtEnydu0iyJrzvwT1cgwK6uCHeV64KcWEzAr0oYJHcs6Smpg9rTad6ZK1V2erdhWozkTVeIJXN60g+Rc/jISmmNgSBp6Uuenh5JNSIdlYVM35iwq/adMLerCcEmW66+xbrJl8c= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=WDvgmDkW; arc=none smtp.client-ip=91.218.175.182 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="WDvgmDkW" X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1753370126; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=gYH+7OzFGHpSlM/+cXLObejEneebIcCwpxyqa2mfSxA=; b=WDvgmDkWbWWZB+va1kleq5YoDlhqFpAyuQOneXTCrd996ZnRls2+16q6oEP5AyohBbMYMF N9fa4P/DJ46622uBfltSO9fQgr6LyvbLeoV1dYJrPOgeRr2Gngi71xOItfbevOPCl6rKcq +Wj2Tj5r6pe41Lq8jOX4vWGDeawxGu0= From: KaFai Wan To: ast@kernel.org, daniel@iogearbox.net, john.fastabend@gmail.com, andrii@kernel.org, martin.lau@linux.dev, eddyz87@gmail.com, song@kernel.org, yonghong.song@linux.dev, kpsingh@kernel.org, sdf@fomichev.me, haoluo@google.com, jolsa@kernel.org, mykolal@fb.com, shuah@kernel.org, kafai.wan@linux.dev, laoar.shao@gmail.com, linux-kernel@vger.kernel.org, bpf@vger.kernel.org, linux-kselftest@vger.kernel.org, leon.hwang@linux.dev Subject: [PATCH bpf-next v4 2/4] bpf: Add log for attaching tracing programs to functions in deny list Date: Thu, 24 Jul 2025 23:14:52 +0800 Message-ID: <20250724151454.499040-3-kafai.wan@linux.dev> In-Reply-To: <20250724151454.499040-1-kafai.wan@linux.dev> References: <20250724151454.499040-1-kafai.wan@linux.dev> Precedence: bulk X-Mailing-List: linux-kselftest@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT Show the rejected function name when attaching tracing programs to functions in deny list. With this change, we know why tracing programs can't attach to functions like __rcu_read_lock() from log. $ ./fentry libbpf: prog '__rcu_read_lock': BPF program load failed: -EINVAL libbpf: prog '__rcu_read_lock': -- BEGIN PROG LOAD LOG -- Attaching tracing programs to function '__rcu_read_lock' is rejected. Suggested-by: Leon Hwang Signed-off-by: KaFai Wan Acked-by: Yafang Shao Acked-by: Yonghong Song --- kernel/bpf/verifier.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 00d287814f12..c24c0d57e595 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -23942,6 +23942,8 @@ static int check_attach_btf_id(struct bpf_verifier_env *env) return ret; } else if (prog->type == BPF_PROG_TYPE_TRACING && btf_id_set_contains(&btf_id_deny, btf_id)) { + verbose(env, "Attaching tracing programs to function '%s' is rejected.\n", + tgt_info.tgt_name); return -EINVAL; } else if ((prog->expected_attach_type == BPF_TRACE_FEXIT || prog->expected_attach_type == BPF_MODIFY_RETURN) && -- 2.43.0