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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 53080C433EF for ; Thu, 18 Nov 2021 08:15:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3B6A361BE6 for ; Thu, 18 Nov 2021 08:15:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S244248AbhKRISt (ORCPT ); Thu, 18 Nov 2021 03:18:49 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42456 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S244484AbhKRIRQ (ORCPT ); Thu, 18 Nov 2021 03:17:16 -0500 Received: from mail-wm1-x34a.google.com (mail-wm1-x34a.google.com [IPv6:2a00:1450:4864:20::34a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 50CB6C06122D for ; Thu, 18 Nov 2021 00:11:48 -0800 (PST) Received: by mail-wm1-x34a.google.com with SMTP id 138-20020a1c0090000000b00338bb803204so1502843wma.1 for ; Thu, 18 Nov 2021 00:11:48 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=rzdCErYR7QVJMqQ7C8iOEn+pKBOJL+BpLP2uqDT2sRI=; b=lywc3NBHZZG/l/NByd9QMLrak/0JWSxz9fkaHSvQpFiu6THhd/Nji8+4etKEu/FWb1 DUr7dTzctJFdTqeiReLlmlOSBqRVuxOd5rYx5nJHm3aM+ZmXYgZ3vl4Ce8tFrt0Av3T1 bf9NeFQD3uLC7xCUpZwxhl9alcSmSnW523ahX1+J5WE1eN8IqUpB8WLaFMwKtqyVR2H5 VBmh+uW9lUYfpnV9Dv/+zhxWz2y1F+L14D0bQuciTgOc/C7axKYJxr+/2pkCLLBSQ4sB E1t7FIYUwhm4GLpE9UPOpx8Eww9R6mgkFTE33GQnZrk37IxG6T6TO6OsAK9RCGF/iBpM yZDA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=rzdCErYR7QVJMqQ7C8iOEn+pKBOJL+BpLP2uqDT2sRI=; b=CrPnZ/vF6RJtNitHI5gGEJ+8hSDF9ynU4zYINEv7VRIJ6ozHSmGAC9AzXEzydrEEsH v+ifTxDlPO3ucITVx3kKXTZCQdUxXjQz4Z6qrIiYqr2BnCyUKxkOnLvf4ZDKgytnvWtO UrRaUkfEw1lgQxbK8RFwQ3Dn3MwjnXU7UTp6MHukOqaZeep6iAsADgZ8VXETfcaubc+9 9RQG3bIJs2x3CtkQJJMhNhpfkagKj+KLVHP618D0DYuzkvwHIknssk7vJDpI/PLaO6yR pZhCvJC3n4iHOuk8R/hRUJh68IZeyfaxu9iu8A6Ohi10bHy+mxxlW8HzdMZ65X2tnf9/ N5sA== X-Gm-Message-State: AOAM5319BYBJtQuEFSHvCG8TkNsfdn3KnJoiaGDUvQ0DVepLcbotbRF+ kE3g2RnadPl1kMp2oo5rfLUm92Ex8Q== X-Google-Smtp-Source: ABdhPJxAWh/BZwpokjufV74uSy9dmYvaQlEFQf441y59AQVEiD0veafOsEsU+5qgKzAWHYtjU5201SdIww== X-Received: from elver.muc.corp.google.com ([2a00:79e0:15:13:7155:1b7:fca5:3926]) (user=elver job=sendgmr) by 2002:a5d:6043:: with SMTP id j3mr28104905wrt.375.1637223106899; Thu, 18 Nov 2021 00:11:46 -0800 (PST) Date: Thu, 18 Nov 2021 09:10:24 +0100 In-Reply-To: <20211118081027.3175699-1-elver@google.com> Message-Id: <20211118081027.3175699-21-elver@google.com> Mime-Version: 1.0 References: <20211118081027.3175699-1-elver@google.com> X-Mailer: git-send-email 2.34.0.rc2.393.gf8c9666880-goog Subject: [PATCH v2 20/23] mm, kcsan: Enable barrier instrumentation From: Marco Elver To: elver@google.com, "Paul E. McKenney" Cc: Alexander Potapenko , Boqun Feng , Borislav Petkov , Dmitry Vyukov , Ingo Molnar , Josh Poimboeuf , Mark Rutland , Peter Zijlstra , Thomas Gleixner , Waiman Long , Will Deacon , kasan-dev@googlegroups.com, linux-arch@vger.kernel.org, linux-doc@vger.kernel.org, linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, x86@kernel.org Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Some memory management calls imply memory barriers that are required to avoid false positives. For example, without the correct instrumentation, we could observe data races of the following variant: T0 | T1 ------------------------+------------------------ | *a = 42; ---+ | kfree(a); | | | | b = kmalloc(..); // b == a <-+ | *b = 42; // not a data race! | Therefore, instrument memory barriers in all allocator code currently not being instrumented in a default build. Signed-off-by: Marco Elver --- mm/Makefile | 2 ++ 1 file changed, 2 insertions(+) diff --git a/mm/Makefile b/mm/Makefile index d6c0042e3aa0..7919cd7f13f2 100644 --- a/mm/Makefile +++ b/mm/Makefile @@ -15,6 +15,8 @@ KCSAN_SANITIZE_slab_common.o := n KCSAN_SANITIZE_slab.o := n KCSAN_SANITIZE_slub.o := n KCSAN_SANITIZE_page_alloc.o := n +# But enable explicit instrumentation for memory barriers. +KCSAN_INSTRUMENT_BARRIERS := y # These files are disabled because they produce non-interesting and/or # flaky coverage that is not a function of syscall inputs. E.g. slab is out of -- 2.34.0.rc2.393.gf8c9666880-goog