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 45F85C4332F for ; Tue, 25 Jan 2022 03:15:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1345457AbiAYDK0 (ORCPT ); Mon, 24 Jan 2022 22:10:26 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41120 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S3411960AbiAYAfP (ORCPT ); Mon, 24 Jan 2022 19:35:15 -0500 Received: from mail-io1-xd2f.google.com (mail-io1-xd2f.google.com [IPv6:2607:f8b0:4864:20::d2f]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 780A8C0DED57 for ; Mon, 24 Jan 2022 14:18:54 -0800 (PST) Received: by mail-io1-xd2f.google.com with SMTP id h7so3459811iof.3 for ; Mon, 24 Jan 2022 14:18:54 -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=VpMGjm8B3WeQMaK4KBi8d6s9JCr8gZTs3NSZcb1bGSQ=; b=XI1pHUfc2pW4d8HUSJpdwe0ZSCnnSPQ8O+n1C42U4hfjvT8URX//WPVfnh2kJe8wmk 1YThtR3VCxkEg94JYIep02cKn/PVStVVLkpBGB0dgVVpwXhywz3ZQCK45ZxZhL9LyXGR fGvqSG2ML3l7pmSJIfeo/IFARSDGxhh+xU6wT5CjBkq7latN9JfFcergZ1PLNismmISD 4zEJgiv4zESLjbr2W0/dGhhJr5dYScLB9VUSwuQQOsCXJYUmJWbi6WR9a/4f5Yti9us2 ZdU0pR3lUAfQkXIoIhuQ/bz8rpjlXcSEuNgAr2qpxw2hZMp98vKiSFTkGrUXTz3LiqJ/ BEAQ== 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=VpMGjm8B3WeQMaK4KBi8d6s9JCr8gZTs3NSZcb1bGSQ=; b=q8uQgnId46nryAD8VFW30OEt7ngxiR0fjglW2NUdwhKsv66J5EEdtOeKtqC/JAy3/V tP5Y4KenB/Hgx2ooxdXYi7KHiuKA+PKkL9wZu+crCJ2DeGZRn7Tba0BuZflyIGRzNm3u 3otOaKwM+0KkVvU/dzKYnFwOxJWE5ricKsBK/cxQd6QEtndWZH2tEX7HvPu+viDGPW/V Km+d/qNigJdW6sHQeo2VzQ2T4H8gnpr128J0Z1orE1fplO8ti2ANjcL5dM+GBRI6zg3y vrCSF0k1qa5r5PuQzAbtMV6nA8oOQsAiyWjitY+wuaf47FddzRWZbp14KS0Vyc11LJXc XlOw== X-Gm-Message-State: AOAM533NRyedx0LGqiqsa73DB5oM8a+2hdtrlWyYXZEq2SUqHAXHkkHe fnqQWBrQEZcNQnzprFIA0y9f4R4H4NhLn+Kad3I= X-Google-Smtp-Source: ABdhPJyG2fqPBpjeOKqyG+4tYytdBCXyZZcqJqqu7Jvct7PgGL6+8lUYsMreYGwxZSOE5WkHDsIw6Z0vGN/jck4lEjg= X-Received: by 2002:a5d:9f01:: with SMTP id q1mr9310438iot.144.1643062733876; Mon, 24 Jan 2022 14:18:53 -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: <20220124185403.468466-3-kennyyu@fb.com> From: Andrii Nakryiko Date: Mon, 24 Jan 2022 14:18:42 -0800 Message-ID: Subject: Re: [PATCH v7 bpf-next 2/4] bpf: Add bpf_copy_from_user_task() helper To: Kenny Yu Cc: Andrii Nakryiko , Alexei Starovoitov , bpf , Daniel Borkmann , Yonghong Song , Alexei Starovoitov , 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 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 () > +} > + > +const struct bpf_func_proto bpf_copy_from_user_task_proto = { > + .func = bpf_copy_from_user_task, > + .gpl_only = false, > + .ret_type = RET_INTEGER, > + .arg1_type = ARG_PTR_TO_UNINIT_MEM, > + .arg2_type = ARG_CONST_SIZE_OR_ZERO, > + .arg3_type = ARG_ANYTHING, > + .arg4_type = ARG_PTR_TO_BTF_ID, > + .arg4_btf_id = &btf_tracing_ids[BTF_TRACING_TYPE_TASK], > + .arg5_type = ARG_ANYTHING > +}; > + [...]