From mboxrd@z Thu Jan 1 00:00:00 1970 From: Daniel Borkmann Subject: Re: [PATCH 2/3] bpf: Remove dead variable Date: Mon, 16 Oct 2017 21:11:47 +0200 Message-ID: <59E50473.7040609@iogearbox.net> References: <20171016181856.12497-1-richard@nod.at> <20171016181856.12497-2-richard@nod.at> <59E5006C.4090303@iogearbox.net> <2297422.9nBBslcvMo@blindfold> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org, ast@kernel.org To: Richard Weinberger Return-path: In-Reply-To: <2297422.9nBBslcvMo@blindfold> Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.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); }