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=-4.0 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 2D0F2C07E98 for ; Mon, 5 Jul 2021 08:04:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 00EB061186 for ; Mon, 5 Jul 2021 08:04:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230009AbhGEIHW (ORCPT ); Mon, 5 Jul 2021 04:07:22 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50660 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230000AbhGEIHW (ORCPT ); Mon, 5 Jul 2021 04:07:22 -0400 Received: from mail-wr1-x42d.google.com (mail-wr1-x42d.google.com [IPv6:2a00:1450:4864:20::42d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A5214C061574; Mon, 5 Jul 2021 01:04:44 -0700 (PDT) Received: by mail-wr1-x42d.google.com with SMTP id i94so20941538wri.4; Mon, 05 Jul 2021 01:04:44 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=19rdSk5GG117pPMoVg+QpxWS28GpyWbwBKt8+Q5v5YQ=; b=h5VjnR4UJnLOgRFsUahLiCKW5XBhNPkkHEY1mzBCB9N3FTs31Z2i6o5XOL4LiUmQNu F9+UOU7eGGTkGao0avAyZeA2/MbpkjMA/lS6AwEjmLmap19g4oQQHdcUoMwu7XghlIby Q0xmIkh6/0lma8qvWmxVaAIWrscxvdpJlwhlHoYqgj6vZqTyH6HgRSSDTO31HjBaYLqZ 2GXhqBEmMgO3QsmIEMU/V0gG6Y0Yi6UjlAfKjZdaqBB7tZBgKLd2hZrZD4WV8idEofTr Y73FjkHS7Ol9hByCPui4wIZgzpy/hsAGJjOqCMyhgWeuKAuPQvLcAIDAQ5B58jzkTkkl q/Qw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:from:to:cc:subject:message-id :references:mime-version:content-disposition:in-reply-to; bh=19rdSk5GG117pPMoVg+QpxWS28GpyWbwBKt8+Q5v5YQ=; b=rY+u0FiLGYgenNmU5sNP1PBLk/PgjMFphwQXdVS7EivurobKoNJ8eNfTic8VWROqxR cxuAJ4DuJq3+ZFyCQCFBqSim/vY1U9f1mj3FBapM+W3/AsS5LXQDxR+wBCKQzTwuW85F lxewRIV/rPkHY+pxCw8DlC7ZGj/af1kca8nxesooYMkNWW3bBDx+Fh2bSspKYgj7DPNG ZzXicxwtIcEQ8DwZKmj3Na+3TdNZ2gAb5qcIZYHC21ao8sbkpd/nPnfQZNdJ3wdG2P6C V+QUfr0Yot4kyM3oYlUIeGYQo07CukR6YIU1VPdTP5cJ0qEy4pnI3V0SpoauGpGdJTeh tROg== X-Gm-Message-State: AOAM533V1HrynfHlFm/BQJagRi4O0EP2usVW0ktD8D2Jdr4R+r6ZCgdN 3WTVmSMvihlYt9xaBN+jwB4= X-Google-Smtp-Source: ABdhPJyZiOJ+iRi+SL5/RJBY1ChtVUqJrFjo3ZgYgp5/0VYHcJGj1BONkhJ1dM1lqCS1e7VhQUv30Q== X-Received: by 2002:a05:6000:154c:: with SMTP id 12mr14431864wry.97.1625472283370; Mon, 05 Jul 2021 01:04:43 -0700 (PDT) Received: from gmail.com (178-164-188-14.pool.digikabel.hu. [178.164.188.14]) by smtp.gmail.com with ESMTPSA id h13sm1393698wrs.68.2021.07.05.01.04.42 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 05 Jul 2021 01:04:42 -0700 (PDT) Sender: Ingo Molnar Date: Mon, 5 Jul 2021 10:04:41 +0200 From: Ingo Molnar To: Masami Hiramatsu Cc: Steven Rostedt , Josh Poimboeuf , X86 ML , Daniel Xu , linux-kernel@vger.kernel.org, bpf@vger.kernel.org, kuba@kernel.org, mingo@redhat.com, ast@kernel.org, Thomas Gleixner , Borislav Petkov , Peter Zijlstra , kernel-team@fb.com, yhs@fb.com, linux-ia64@vger.kernel.org, Abhishek Sagar , Andrii Nakryiko Subject: Re: [PATCH -tip v8 08/13] arm: kprobes: Make a space for regs->ARM_pc at kretprobe_trampoline Message-ID: References: <162399992186.506599.8457763707951687195.stgit@devnote2> <162399999702.506599.16339931387573094059.stgit@devnote2> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <162399999702.506599.16339931387573094059.stgit@devnote2> Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org * Masami Hiramatsu wrote: > Change kretprobe_trampoline to make a space for regs->ARM_pc so that > kretprobe_trampoline_handler can call instruction_pointer_set() > safely. The idiom is "make space", but in any case, what does this mean? Was the stack frame set up in kretprobe_trampoline() and calling trampoline_handler() buggy? If yes, then explain the bad effects of the bug, and make all of this clear in the title & changelog. Thanks, Ingo