From patchwork Mon Apr 23 06:03:57 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yonghong Song X-Patchwork-Id: 902768 X-Patchwork-Delegate: bpf@iogearbox.net Return-Path: X-Original-To: patchwork-incoming-netdev@ozlabs.org Delivered-To: patchwork-incoming-netdev@ozlabs.org Authentication-Results: ozlabs.org; spf=none (mailfrom) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=netdev-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=pass (p=none dis=none) header.from=fb.com Authentication-Results: ozlabs.org; dkim=pass (1024-bit key; unprotected) header.d=fb.com header.i=@fb.com header.b="Au6OeXSB"; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 40Twsf3BYTz9s0p for ; Mon, 23 Apr 2018 16:04:54 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754044AbeDWGEw (ORCPT ); Mon, 23 Apr 2018 02:04:52 -0400 Received: from mx0a-00082601.pphosted.com ([67.231.145.42]:47794 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751932AbeDWGEG (ORCPT ); Mon, 23 Apr 2018 02:04:06 -0400 Received: from pps.filterd (m0044012.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.16.0.22/8.16.0.22) with SMTP id w3N5t9Kk011496 for ; Sun, 22 Apr 2018 23:04:06 -0700 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fb.com; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-type; s=facebook; bh=ewFp6j7520szxC/2y9LxyUYj4h6dWtdgp0jz7ib01yU=; b=Au6OeXSBk9Zbs0z++3zLwdCpUbk2zbFIIhysuC5EyoKBf0YdsAKxYahX6M89bN0JJD3A 1pJ47NjUX7JvAmYkn6n8SVEf+AB1L2BL0udwI4jhSijWkePGBXynpO2Z+s76ZbvVTLUV s+SahbCM/Gn5ePyVCLec9mM1lWp4duCs3nU= Received: from mail.thefacebook.com ([199.201.64.23]) by mx0a-00082601.pphosted.com with ESMTP id 2hh39xrheq-3 (version=TLSv1 cipher=ECDHE-RSA-AES256-SHA bits=256 verify=NOT) for ; Sun, 22 Apr 2018 23:04:05 -0700 Received: from mx-out.facebook.com (192.168.52.123) by PRN-CHUB09.TheFacebook.com (192.168.16.19) with Microsoft SMTP Server id 14.3.361.1; Sun, 22 Apr 2018 23:04:04 -0700 Received: by devbig474.prn1.facebook.com (Postfix, from userid 128203) id 86BA9E411BC; Sun, 22 Apr 2018 23:04:03 -0700 (PDT) Smtp-Origin-Hostprefix: devbig From: Yonghong Song Smtp-Origin-Hostname: devbig474.prn1.facebook.com To: , , CC: Smtp-Origin-Cluster: prn1c29 Subject: [PATCH bpf-next v4 04/10] bpf: remove never-hit branches in verifier adjust_scalar_min_max_vals Date: Sun, 22 Apr 2018 23:03:57 -0700 Message-ID: <20180423060403.1035526-5-yhs@fb.com> X-Mailer: git-send-email 2.9.5 In-Reply-To: <20180423060403.1035526-1-yhs@fb.com> References: <20180423060403.1035526-1-yhs@fb.com> X-FB-Internal: Safe MIME-Version: 1.0 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:, , definitions=2018-04-23_03:, , signatures=0 X-Proofpoint-Spam-Reason: safe X-FB-Internal: Safe Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org In verifier function adjust_scalar_min_max_vals, when src_known is false and the opcode is BPF_LSH/BPF_RSH, early return will happen in the function. So remove the branch in handling BPF_LSH/BPF_RSH when src_known is false. Signed-off-by: Yonghong Song --- kernel/bpf/verifier.c | 11 ++--------- 1 file changed, 2 insertions(+), 9 deletions(-) diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index d00bf53..1bbb43d 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -2932,10 +2932,7 @@ static int adjust_scalar_min_max_vals(struct bpf_verifier_env *env, dst_reg->umin_value <<= umin_val; dst_reg->umax_value <<= umax_val; } - if (src_known) - dst_reg->var_off = tnum_lshift(dst_reg->var_off, umin_val); - else - dst_reg->var_off = tnum_lshift(tnum_unknown, umin_val); + dst_reg->var_off = tnum_lshift(dst_reg->var_off, umin_val); /* We may learn something more from the var_off */ __update_reg_bounds(dst_reg); break; @@ -2963,11 +2960,7 @@ static int adjust_scalar_min_max_vals(struct bpf_verifier_env *env, */ dst_reg->smin_value = S64_MIN; dst_reg->smax_value = S64_MAX; - if (src_known) - dst_reg->var_off = tnum_rshift(dst_reg->var_off, - umin_val); - else - dst_reg->var_off = tnum_rshift(tnum_unknown, umin_val); + dst_reg->var_off = tnum_rshift(dst_reg->var_off, umin_val); dst_reg->umin_value >>= umax_val; dst_reg->umax_value >>= umin_val; /* We may learn something more from the var_off */