From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753687AbdJPTLz (ORCPT ); Mon, 16 Oct 2017 15:11:55 -0400 Received: from www62.your-server.de ([213.133.104.62]:49563 "EHLO www62.your-server.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752007AbdJPTLy (ORCPT ); Mon, 16 Oct 2017 15:11:54 -0400 Message-ID: <59E50473.7040609@iogearbox.net> Date: Mon, 16 Oct 2017 21:11:47 +0200 From: Daniel Borkmann User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.7.0 MIME-Version: 1.0 To: Richard Weinberger CC: netdev@vger.kernel.org, linux-kernel@vger.kernel.org, ast@kernel.org Subject: Re: [PATCH 2/3] bpf: Remove dead variable References: <20171016181856.12497-1-richard@nod.at> <20171016181856.12497-2-richard@nod.at> <59E5006C.4090303@iogearbox.net> <2297422.9nBBslcvMo@blindfold> In-Reply-To: <2297422.9nBBslcvMo@blindfold> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit X-Authenticated-Sender: daniel@iogearbox.net Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10/16/2017 08:59 PM, Richard Weinberger wrote: > Am Montag, 16. Oktober 2017, 20:54:36 CEST schrieb Daniel Borkmann: >> On 10/16/2017 08:18 PM, Richard Weinberger wrote: >>> task is never used in bpf_get_current_uid_gid(), kill it. >>> >>> Signed-off-by: Richard Weinberger >>> --- >>> >>> kernel/bpf/helpers.c | 1 - >>> 1 file changed, 1 deletion(-) >>> >>> diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c >>> index e8845adcd15e..511c9d522cfc 100644 >>> --- a/kernel/bpf/helpers.c >>> +++ b/kernel/bpf/helpers.c >>> @@ -131,7 +131,6 @@ const struct bpf_func_proto >>> bpf_get_current_pid_tgid_proto = {> >>> BPF_CALL_0(bpf_get_current_uid_gid) >>> { >>> >>> - struct task_struct *task = current; >>> >>> kuid_t uid; >>> kgid_t gid; >> >> Needs to be squashed into patch 1/3? > > I can squash it into 1/3, I kept it that way because > even without 1/3 this variable is unused. Hmm, the helper looks like the below. In patch 1/3 you removed the 'if (unlikely(!task))' test where the variable was used before, so 2/3 without the 1/3 would result in a compile error. BPF_CALL_0(bpf_get_current_uid_gid) { struct task_struct *task = current; kuid_t uid; kgid_t gid; if (unlikely(!task)) return -EINVAL; current_uid_gid(&uid, &gid); return (u64) from_kgid(&init_user_ns, gid) << 32 | from_kuid(&init_user_ns, uid); }