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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9B7E4C433EF for ; Tue, 25 Jan 2022 05:49:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239691AbiAYFtC (ORCPT ); Tue, 25 Jan 2022 00:49:02 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55768 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238935AbiAYFqi (ORCPT ); Tue, 25 Jan 2022 00:46:38 -0500 Received: from mail-pf1-x42a.google.com (mail-pf1-x42a.google.com [IPv6:2607:f8b0:4864:20::42a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A2A7BC035456 for ; Mon, 24 Jan 2022 20:06:23 -0800 (PST) Received: by mail-pf1-x42a.google.com with SMTP id v74so14912451pfc.1 for ; Mon, 24 Jan 2022 20:06:23 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=dEF6b3Ugv6J965Xw+B5fepuJ/VFbAOycmCFtYxAAeGM=; b=oCbbP5aeocniONQebDYdLjS1SnmkOwNBhHRBqwBlpzSuQD2qALC+VDvfFli0ay9MXG qcDCs1zk1udVacmvD0qoEWPCOb72OiU37leGw7Vdl8A+vIGlTNgGXiZvsttqR6D0idUy qe6gcN+cVv5fhp4f8HY4Fy7uPC8ibFCppz5okG0itZQZlXMPxMhTBcghMItGF1Rj0Kl9 xHYmQ0/8SB3imT/ln3RyGyCMdMkSTPf2AUEnMse7D+f/E2fkfTxnCBO52HWdZvSW24Hd hu8d7k/QsEpE/p9m5RF8Sz1hqt3FBQB3reFcqcn2yDb1TBtDHBKVygzLHs5Tf88yWtoI aJ2A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=dEF6b3Ugv6J965Xw+B5fepuJ/VFbAOycmCFtYxAAeGM=; b=SRu/MZmsNiYV/TlA3dCim6by5wQ3eu/NSLvI5fafXCXasrlW17LlZeznqE9MPAN6eL XP6eKek/tPdb9vCxcfGDYQ+AVl48Dl5lXcUbMY+twzop0HwQC5DU0qL2bSXFU5gdACLw MU/ap8F6rHjBryIHXhiYwGdmNPYARTurp00KqO4DINxk5EBmD9280MmoHN5jdT9mDLFy LoZe0tnU8ErSoqMZ6zL8YhO8QJ5Yw8FdF0Tm5LKrLdSatQZ1q+i/lkR0w1TF7dX2/cK3 am4qqTk32FYpC2NLFPuVhRrLvGlQO49Xuc9iV4HaKVwshbZ9XRNqqxuDq8U6q5QIU57W B6mA== X-Gm-Message-State: AOAM531wvN1/8IIeMrC79b7e6SwyEqfB3ZqNK4xD9NePCW00+Xb8s1eh HSjHfus4TSI6EdJ2ZJV5N5gGWbZdgAu8g98H510= X-Google-Smtp-Source: ABdhPJw10/WsNhruDRz7M4eCoeAhmkMTtJOpViVRfGaGbqKJoD1vbcEVXrZ6BoyssHQ5KqMSgVmj+xKQ+XVyRFjEMfw= X-Received: by 2002:a63:1ca:: with SMTP id 193mr13744660pgb.497.1643083583010; Mon, 24 Jan 2022 20:06:23 -0800 (PST) MIME-Version: 1.0 References: <20220113233158.1582743-1-kennyyu@fb.com> <20220124185403.468466-1-kennyyu@fb.com> <20220124185403.468466-3-kennyyu@fb.com> In-Reply-To: From: Alexei Starovoitov Date: Mon, 24 Jan 2022 20:06:11 -0800 Message-ID: Subject: Re: [PATCH v7 bpf-next 2/4] bpf: Add bpf_copy_from_user_task() helper To: Andrii Nakryiko Cc: Kenny Yu , Andrii Nakryiko , Alexei Starovoitov , bpf , Daniel Borkmann , Yonghong Song , Gabriele Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org On Mon, Jan 24, 2022 at 2:18 PM Andrii Nakryiko wrote: > > On Mon, Jan 24, 2022 at 10:54 AM Kenny Yu wrote: > > > > This adds a helper for bpf programs to read the memory of other > > tasks. > > > > As an example use case at Meta, we are using a bpf task iterator program > > and this new helper to print C++ async stack traces for all threads of > > a given process. > > > > Signed-off-by: Kenny Yu > > --- > > LGTM. > > Acked-by: Andrii Nakryiko > > > include/linux/bpf.h | 1 + > > include/uapi/linux/bpf.h | 11 +++++++++++ > > kernel/bpf/helpers.c | 34 ++++++++++++++++++++++++++++++++++ > > kernel/trace/bpf_trace.c | 2 ++ > > tools/include/uapi/linux/bpf.h | 11 +++++++++++ > > 5 files changed, 59 insertions(+) > > > > [...] > > > + ret = access_process_vm(tsk, (unsigned long)user_ptr, dst, size, 0); > > + if (ret == size) > > + return 0; > > + > > + memset(dst, 0, size); > > + /* Return -EFAULT for partial read */ > > + return (ret < 0) ? ret : -EFAULT; > > nit: unnecessary () I fixed it while applying. Also added a few unlikely(). Thanks everyone!