From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.3 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1EEF9CA9EC7 for ; Sat, 2 Nov 2019 20:08:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E78B8214AF for ; Sat, 2 Nov 2019 20:08:55 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="h7IvU709" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726861AbfKBUIz (ORCPT ); Sat, 2 Nov 2019 16:08:55 -0400 Received: from mail-pg1-f194.google.com ([209.85.215.194]:45067 "EHLO mail-pg1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726523AbfKBUIz (ORCPT ); Sat, 2 Nov 2019 16:08:55 -0400 Received: by mail-pg1-f194.google.com with SMTP id r1so8588628pgj.12; Sat, 02 Nov 2019 13:08:55 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=zXYT/ZeHsCXMOP8AZMsrYS79rL9tXXrExzyfPs19B/o=; b=h7IvU709Edudo+yyjBuJBbYljj67d8fFRjiKkFYe1tcSdWoViubaKuTLw+idC3ecKQ U7inLhioU6kn0mJS1MFqHAo0uEhpnJKWNzsEan+w3ifT5Rfr9mtUbGiQi3mMaDomeGYN 4Oq/9QKx0GfHPem10oPvJxFidW5I4tgc37UAjU7LWTO905PBu2nMOHbHpLp9/3bvUtE0 7iv3v61UB4O/Qvza8RecM8qZI6ILBqq7Er6rbCn5bSqUj/WJb0BXkg3OrMSQHQd+12X3 Jk6RsEMXBLd8Uo4XpP4mBR18giZWRs+Vo+UbRR+LmjUEolb8IPPQWKW2MMkWDbjngF+y 9dJg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=zXYT/ZeHsCXMOP8AZMsrYS79rL9tXXrExzyfPs19B/o=; b=C6p7dsT67PBDA+ivnHI7hvNt79Q8izfHKYXFBHtosXFvyV1BdO9RSGA/0wVGzVY/or mgzWFs/1EW2N7gfs4XJzJqsP+oQhbHa2wVEgrXvjk194U5F4liTOlkx0X7uZxzl+8M5n VP0FrDypThr9Yy8ZExG9rZ0gAPq+jutGtk//DZHMsWfB9U7KBeHRM4apmex8hiFjxgB3 nazjD1y/4ERj8f5vo7kfmQUtakV7lnWzXmaMErBpZgC1ER4Vltq/KWjAxsajMHlIkf3w ZxV/uT2BaA4ZN+S+oa14SMVHgZ6Pw6dZznqRaOJPYy5t4kI5jmuBFjTv+a+EATrAat42 yhIQ== X-Gm-Message-State: APjAAAXGQFbcDD9BAE6VO9QKG1Tmq9+ibKN961iBCVZCnPe+I6RyZmQF NIvxOs1wpQnykV9E76gBHwo= X-Google-Smtp-Source: APXvYqzky6bIyPy8AJunDvpI4UPDIRRI8D8sEIBrqhtW6ZSz22wzKSj8yzav+NjNlNycgOmTSubxtQ== X-Received: by 2002:a65:4489:: with SMTP id l9mr2358594pgq.106.1572725334359; Sat, 02 Nov 2019 13:08:54 -0700 (PDT) Received: from ast-mbp.dhcp.thefacebook.com ([2620:10d:c090:180::f3bc]) by smtp.gmail.com with ESMTPSA id s69sm231025pgs.65.2019.11.02.13.08.53 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Sat, 02 Nov 2019 13:08:53 -0700 (PDT) Date: Sat, 2 Nov 2019 13:08:52 -0700 From: Alexei Starovoitov To: Daniel Borkmann Cc: bpf@vger.kernel.org, netdev@vger.kernel.org, ast@kernel.org, andrii.nakryiko@gmail.com, john.fastabend@gmail.com Subject: Re: [PATCH bpf-next v3 0/8] Fix BPF probe memory helpers Message-ID: <20191102200850.cyf3ql5ao43p7vmz@ast-mbp.dhcp.thefacebook.com> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: NeoMutt/20180223 Sender: bpf-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org On Sat, Nov 02, 2019 at 12:17:55AM +0100, Daniel Borkmann wrote: > This set adds probe_read_{user,kernel}(), probe_read_str_{user,kernel}() > helpers, fixes probe_write_user() helper and selftests. For details please > see individual patches. > > Thanks! > > v2 -> v3: > - noticed two more things that are fixed in here: > - bpf uapi helper description used 'int size' for *_str helpers, now u32 > - we need TASK_SIZE_MAX + guard page on x86-64 in patch 2 otherwise > we'll trigger the 00c42373d397 warn as well, so full range covered now Applied and I wish I could say: "queued up for -stable". The warning added by commit 00c42373d397 ("x86-64: add warning for non-canonical user access address dereferences") dumps the stack trace that looks like kernel panic. It was reported numerous times by scared users and crash detection tools. Until now bpf tracing programs couldn't be fixed to avoid that warning. This patch set is a big step forward solving user vs kernel access issue. User space tool 'bpftrace' provisioned language feature 'kaddr' and 'uaddr' in anticipation of the bpf_probe_read_user() helper. Thank you Daniel for implementing this fix.