From patchwork Tue Jun 16 05:04:30 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrii Nakryiko X-Patchwork-Id: 1309986 X-Patchwork-Delegate: bpf@iogearbox.net Return-Path: X-Original-To: incoming-bpf@patchwork.ozlabs.org Delivered-To: patchwork-incoming-bpf@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org (client-ip=23.128.96.18; helo=vger.kernel.org; envelope-from=bpf-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=pass (p=reject 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.a=rsa-sha256 header.s=facebook header.b=YN835TCv; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by ozlabs.org (Postfix) with ESMTP id 49mGMz6kBxz9sR4 for ; Tue, 16 Jun 2020 15:04:47 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725928AbgFPFEn (ORCPT ); Tue, 16 Jun 2020 01:04:43 -0400 Received: from mx0a-00082601.pphosted.com ([67.231.145.42]:45238 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725710AbgFPFEn (ORCPT ); Tue, 16 Jun 2020 01:04:43 -0400 Received: from pps.filterd (m0148461.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id 05G53Hkd025069 for ; Mon, 15 Jun 2020 22:04:42 -0700 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fb.com; h=from : to : cc : subject : date : message-id : mime-version : content-transfer-encoding : content-type; s=facebook; bh=GkEct7hq4y31Z+EChUTSGdzyQUOiVP/OFvqPi7EQuZc=; b=YN835TCv3FLHimtQQB8yhzz/Vla9JtO6uJ0u0n5f7iJ4psbblSdv4AmMnshwH4uxp/wQ v4YUl6IjNbIcwwLy6+8RkOq+Lqj5nOOYcLs/yfT9BdumrAaJzlSq59UR4MDAoAtmElOq Dgh8U0GyjtoNsWVddqTooAaK/N6NFouD5kc= Received: from mail.thefacebook.com ([163.114.132.120]) by mx0a-00082601.pphosted.com with ESMTP id 31nesqr6yb-2 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Mon, 15 Jun 2020 22:04:42 -0700 Received: from intmgw002.08.frc2.facebook.com (2620:10d:c085:208::f) by mail.thefacebook.com (2620:10d:c085:21d::6) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.1979.3; Mon, 15 Jun 2020 22:04:41 -0700 Received: by devbig012.ftw2.facebook.com (Postfix, from userid 137359) id 9E8CC2EC2F00; Mon, 15 Jun 2020 22:04:34 -0700 (PDT) Smtp-Origin-Hostprefix: devbig From: Andrii Nakryiko Smtp-Origin-Hostname: devbig012.ftw2.facebook.com To: , , , CC: , , Andrii Nakryiko , Christoph Hellwig Smtp-Origin-Cluster: ftw2c04 Subject: [PATCH bpf 1/2] bpf: bpf_probe_read_kernel_str() has to return amount of data read on success Date: Mon, 15 Jun 2020 22:04:30 -0700 Message-ID: <20200616050432.1902042-1-andriin@fb.com> X-Mailer: git-send-email 2.24.1 MIME-Version: 1.0 X-FB-Internal: Safe X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.216, 18.0.687 definitions=2020-06-15_11:2020-06-15,2020-06-15 signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 spamscore=0 cotscore=-2147483648 mlxscore=0 adultscore=0 bulkscore=0 suspectscore=8 clxscore=1015 priorityscore=1501 malwarescore=0 mlxlogscore=831 lowpriorityscore=0 phishscore=0 impostorscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2004280000 definitions=main-2006160036 X-FB-Internal: deliver Sender: bpf-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org During recent refactorings, bpf_probe_read_kernel_str() started returning 0 on success, instead of amount of data successfully read. This majorly breaks applications relying on bpf_probe_read_kernel_str() and bpf_probe_read_str() and their results. Fix this by returning actual number of bytes read. Cc: Christoph Hellwig Fixes: 8d92db5c04d1 ("bpf: rework the compat kernel probe handling") Signed-off-by: Andrii Nakryiko Reviewed-by: Christoph Hellwig Acked-by: John Fastabend --- kernel/trace/bpf_trace.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index e729c9e587a0..a3ac7de98baa 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -241,7 +241,7 @@ bpf_probe_read_kernel_str_common(void *dst, u32 size, const void *unsafe_ptr) if (unlikely(ret < 0)) goto fail; - return 0; + return ret; fail: memset(dst, 0, size); return ret;