From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) (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 C159730CDAC; Thu, 18 Sep 2025 15:31:34 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=216.40.44.16 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758209496; cv=none; b=nKmkHqjKuH01FUco/sO2z9cjEbwz59cfdOZN1hYCKgkA+VC57tP7DeLexnGpvEoaPgJPinGELTvsPCXcH9VpWheZfOy78A2bdfsEs+gWebTDU5o4GDLdD6k0YDkyCbDa4PaXsqx93f4ap2Ijv0ZRQ4e/mUeXPBsi2HF2FVoTxaw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758209496; c=relaxed/simple; bh=QZCy1OJjqBJh0gFIG7MWM+0jYLNNxOxd2PqQq5mo5Yo=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=PnMScQxMII1i3+DAU1yEd0Zax+66YwGRoljzWM49Yw37sDMZD1aOBYX4T9O7hL4C+0LBhLJZ8dU2VETwrYz/+Fbp+TY9xR2Oj5N+jClZZsIMR+KW4i/vRKjXdCubPJmgHnMFzSAAM7r2wbA26ZOskSgjArNBzf0RBG60op8DMng= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=goodmis.org; spf=pass smtp.mailfrom=goodmis.org; arc=none smtp.client-ip=216.40.44.16 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=goodmis.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=goodmis.org Received: from omf05.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay02.hostedemail.com (Postfix) with ESMTP id 90BC213A0CD; Thu, 18 Sep 2025 15:31:31 +0000 (UTC) Received: from [HIDDEN] (Authenticated sender: rostedt@goodmis.org) by omf05.hostedemail.com (Postfix) with ESMTPA id 26ACE20016; Thu, 18 Sep 2025 15:31:26 +0000 (UTC) Date: Thu, 18 Sep 2025 11:32:34 -0400 From: Steven Rostedt To: Fuyu Zhao Cc: Jiri Olsa , Song Liu , ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org, martin.lau@linux.dev, yonghong.song@linux.dev, haoluo@google.com, eddyz87@gmail.com, kpsingh@kernel.org, sdf@fomichev.me, mhiramat@kernel.org, mathieu.desnoyers@efficios.com, shuah@kernel.org, willemb@google.com, kerneljasonxing@gmail.com, paul.chaignon@gmail.com, chen.dylane@linux.dev, memxor@gmail.com, martin.kelly@crowdstrike.com, ameryhung@gmail.com, linux-kernel@vger.kernel.org, bpf@vger.kernel.org, linux-trace-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, yikai.lin@vivo.com Subject: Re: [RFC PATCH bpf-next v1 0/3] bpf: Add BPF program type for overriding tracepoint probes Message-ID: <20250918113234.3f9e556a@gandalf.local.home> In-Reply-To: <9cb5b3d5-97bb-4165-9a84-394d3d45a20e@vivo.com> References: <20250917072242.674528-1-zhaofuyu@vivo.com> <9cb5b3d5-97bb-4165-9a84-394d3d45a20e@vivo.com> X-Mailer: Claws Mail 3.20.0git84 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Stat-Signature: xexywcpfgjs6zafak66u594a4iimzte3 X-Rspamd-Server: rspamout01 X-Rspamd-Queue-Id: 26ACE20016 X-Session-Marker: 726F737465647440676F6F646D69732E6F7267 X-Session-ID: U2FsdGVkX1/5VKD1WZaH+qlJjD8FFIkR8XM8YVm/Fvc= X-HE-Tag: 1758209485-346587 X-HE-Meta: U2FsdGVkX1/j1e4fDuVmFwYkOTLvvV2NOP6rFhn6Fkk6YvTNGBQsKDcC8yTW9CMKh9nnzfqWO430S3SN+A1gNHnPGJbdafl1IgHkggXCdvGXv3cV4YAjThA8kjwC/6+Ta1tMmod474GzfgIzXP2sGMDt4FTW704Q1mC7O6aRUK2aOt0h9KPmkcWRcOghUTCdRyhfAndY2VCWXPVZ5GvCtSubejUa1vn64VQ2rb+BHZXYqoLTJ7QLwzJdssI8sEbZpBmk9X92AzVZK8w/nOoNGIZy9XxvXLkd4i2r2qlcUbpZKsOUkpqsxz1YsvF0CdyPc/7DSIVfOImbMgwZUwVtBXaS3KBmlrnP On Thu, 18 Sep 2025 21:15:57 +0800 Fuyu Zhao wrote: > As for the reason not to unregister and register a new callback: > callbacks registered directly inside the kernel cannot be unregistered from > user space. From user space, we can only attach additional callbacks > with BPF programs, but can not remove or replace the ones already > registered in the kernel. Therefore, an override mechanism is needed. The fact that user space cannot unregister or override the current callbacks, to me is a feature and not a bug. -- Steve