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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 975FDC433F5 for ; Tue, 29 Mar 2022 20:11:58 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id CDC588D0002; Tue, 29 Mar 2022 16:11:57 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id C8BC78D0001; Tue, 29 Mar 2022 16:11:57 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id B54F38D0002; Tue, 29 Mar 2022 16:11:57 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0196.hostedemail.com [216.40.44.196]) by kanga.kvack.org (Postfix) with ESMTP id A8FB08D0001 for ; Tue, 29 Mar 2022 16:11:57 -0400 (EDT) Received: from smtpin24.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id 65BBC1828D824 for ; Tue, 29 Mar 2022 20:11:57 +0000 (UTC) X-FDA: 79298519874.24.BF3B593 Received: from mail-io1-f50.google.com (mail-io1-f50.google.com [209.85.166.50]) by imf29.hostedemail.com (Postfix) with ESMTP id 0DCC8120006 for ; Tue, 29 Mar 2022 20:11:56 +0000 (UTC) Received: by mail-io1-f50.google.com with SMTP id z6so22420630iot.0 for ; Tue, 29 Mar 2022 13:11:56 -0700 (PDT) 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=5Hh0vVsE5NsIgTehOa3nlosmMfHWGMN9c6MMyMO5zeA=; b=RCfMNSkuStRnGHPd8TI50xmq7vkhNjP1+3HBy1AUUbB8DmgOc0CeB/s2yIVkc0VV2q bb3IaX3O/QNfu92Et0gyXFhsOA9+CYX0+sQvitrSQuqIIs8b0WiXb+e0us6ol5URb8z5 q2JYqiKu2DmH3w+opGujLnnCMgY8VxNseu1l4+qsFtWTHcfhP3prOnA81Huz615X6ma/ gGzH73c7SVkFU6q37izzYhwLRK0ZDbBPXEgEug8Oxc4rOSNPVfPhSO+xh9sWe42t8nDo KIcWdKHr/IWvGkjhIAHQF7+f6dWr5jxI5Hna+4bIEpHK9u5eMgTrk3/iVHYFKcPZKr/J wvyQ== 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=5Hh0vVsE5NsIgTehOa3nlosmMfHWGMN9c6MMyMO5zeA=; b=JDrJqyli6F1z+9EV/QkUVB1e5m8IetqRYFBtxgCBhjp57LvtHer51QFc8TwjizyE2Q X11/9WO3JSlRa+IQay0m1FGzO/aERG6kly4AeTEfj5FaLOVRfKmNFon1O3OGHKQ2DSY4 YeLmT9wrUczCxl3WXGp+cU7NO+KgpqtkuseKOgrEPnVXtZ8d4UnF7g+fflf/f2oRggW1 zag/Ulzb+Tnew4Qf/xofeJ+z7j6MlG9+cflY66XHBaaK6raYkzyP3R7iExp3PATu9abz OhNBet7S7YTp4pqdEYHFyU8Me/RslVylSg2kP5uRArYM9hrXe7suzqENQ2KbEHOLDPJB 80WA== X-Gm-Message-State: AOAM531zN8xzgA7Ybu3NcozQrUSTzovmXTc9Ded8Pweo1Dcf7GejbOgI GDoKrZfFbPkA9Hks2+SPc7tp3nstYw5twXKWcpE= X-Google-Smtp-Source: ABdhPJyCArHsnFq1o+gDamX8A/FwJjCgzvbDIxBdKui/ziva4Bj/hhbmEWYcj6j0CFZqKXC43krf+JbpRKNmgtj1nJo= X-Received: by 2002:a05:6638:2113:b0:321:4e19:b04d with SMTP id n19-20020a056638211300b003214e19b04dmr18181370jaj.71.1648584716304; Tue, 29 Mar 2022 13:11:56 -0700 (PDT) MIME-Version: 1.0 References: In-Reply-To: From: Andrey Konovalov Date: Tue, 29 Mar 2022 22:11:45 +0200 Message-ID: Subject: Re: [PATCH v2 0/4] kasan, arm64, scs, stacktrace: collect stack traces from Shadow Call Stack To: Marco Elver Cc: andrey.konovalov@linux.dev, Alexander Potapenko , Catalin Marinas , Will Deacon , Andrew Morton , Dmitry Vyukov , Andrey Ryabinin , kasan-dev , Mark Rutland , Vincenzo Frascino , Sami Tolvanen , Peter Collingbourne , Evgenii Stepanov , Florian Mayer , Linux Memory Management List , LKML , Andrey Konovalov Content-Type: text/plain; charset="UTF-8" Authentication-Results: imf29.hostedemail.com; dkim=pass header.d=gmail.com header.s=20210112 header.b=RCfMNSku; spf=pass (imf29.hostedemail.com: domain of andreyknvl@gmail.com designates 209.85.166.50 as permitted sender) smtp.mailfrom=andreyknvl@gmail.com; dmarc=pass (policy=none) header.from=gmail.com X-Stat-Signature: 8t3rt3dm3g1ew1hihu73tyj3o3ct5jxa X-Rspam-User: X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: 0DCC8120006 X-HE-Tag: 1648584716-942750 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Tue, Mar 29, 2022 at 8:36 PM Andrey Konovalov wrote: > > On Mon, Mar 28, 2022 at 2:36 PM Marco Elver wrote: > > > > > Changes v1->v2: > > > - Provide a kernel-wide stack_trace_save_shadow() interface for collecting > > > stack traces from shadow stack. > > > - Use ptrauth_strip_insn_pac() and READ_ONCE_NOCHECK, see the comments. > > > - Get SCS pointer from x18, as per-task value is meant to save the SCS > > > value on CPU switches. > > > - Collect stack frames from SDEI and IRQ contexts. > > > > Do any of these new changes introduce new (noticeable) overhead (in > > particular patch 2)? > > I'll measure the overheads and include the results into v3. Thanks! Hm, looks like the overhead is overly significant: ~5%. I'll explore a different approach in v3 instead.