From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from dedi548.your-server.de (dedi548.your-server.de [85.10.215.148]) by sourceware.org (Postfix) with ESMTPS id 2E20C388E819 for ; Mon, 19 Oct 2020 15:55:45 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org 2E20C388E819 Authentication-Results: sourceware.org; dmarc=none (p=none dis=none) header.from=embedded-brains.de Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=sebastian.huber@embedded-brains.de Received: from sslproxy02.your-server.de ([78.47.166.47]) by dedi548.your-server.de with esmtpsa (TLSv1.3:TLS_AES_256_GCM_SHA384:256) (Exim 4.92.3) (envelope-from ) id 1kUXVg-0003od-66 for newlib@sourceware.org; Mon, 19 Oct 2020 17:55:44 +0200 Received: from [82.100.198.138] (helo=mail.embedded-brains.de) by sslproxy02.your-server.de with esmtpsa (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.92) (envelope-from ) id 1kUXVb-000Xhx-3G for newlib@sourceware.org; Mon, 19 Oct 2020 17:55:39 +0200 Received: from localhost (localhost.localhost [127.0.0.1]) by mail.embedded-brains.de (Postfix) with ESMTP id CEE092A165B for ; Mon, 19 Oct 2020 17:54:26 +0200 (CEST) Received: from mail.embedded-brains.de ([127.0.0.1]) by localhost (zimbra.eb.localhost [127.0.0.1]) (amavisd-new, port 10032) with ESMTP id jJ-lis1DZTLm for ; Mon, 19 Oct 2020 17:54:26 +0200 (CEST) Received: from localhost (localhost.localhost [127.0.0.1]) by mail.embedded-brains.de (Postfix) with ESMTP id 65EEC2A1682 for ; Mon, 19 Oct 2020 17:54:26 +0200 (CEST) X-Virus-Scanned: amavisd-new at zimbra.eb.localhost Received: from mail.embedded-brains.de ([127.0.0.1]) by localhost (zimbra.eb.localhost [127.0.0.1]) (amavisd-new, port 10026) with ESMTP id 4bVBVHwSdRwT for ; Mon, 19 Oct 2020 17:54:26 +0200 (CEST) Received: from linux-diu0.suse (unknown [192.168.96.161]) by mail.embedded-brains.de (Postfix) with ESMTP id 4C39D2A1687 for ; Mon, 19 Oct 2020 17:54:26 +0200 (CEST) From: Sebastian Huber To: newlib@sourceware.org Subject: [PATCH 5/5] amd64: prevent KCSan false positives on LAPIC mapping Date: Mon, 19 Oct 2020 17:55:37 +0200 Message-Id: <20201019155537.15290-6-sebastian.huber@embedded-brains.de> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20201019155537.15290-1-sebastian.huber@embedded-brains.de> References: <20201019155537.15290-1-sebastian.huber@embedded-brains.de> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Authenticated-Sender: smtp-embedded@poldinet.de X-Virus-Scanned: Clear (ClamAV 0.102.4/25962/Mon Oct 19 15:57:02 2020) X-Spam-Status: No, score=-11.8 required=5.0 tests=BAYES_00, GIT_PATCH_0, KAM_DMARC_STATUS, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on server2.sourceware.org X-BeenThere: newlib@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Newlib mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 19 Oct 2020 15:55:46 -0000 From: jah For configurations without x2APIC support (guests, older hardware), the g= lobal LAPIC MMIO mapping will trigger false-positive KCSan reports as it will a= ppear that multiple CPUs are concurrently reading and writing the same address. This isn't actually true, as the underlying physical access will be perfo= rmed on the local CPU's APIC. Additionally, because LAPIC access can happen du= ring event timer configuration, the resulting KCSan printf can produce a panic= due to attempted recursion on event timer resources. Add a __nosanitizethread preprocessor define to prevent the compiler from inserting TSan hooks, and apply it to the x86 LAPIC accessors. PR: 249149 Reported by: gbe Reviewed by: andrew, kib Tested by: gbe Differential Revision: https://reviews.freebsd.org/D26354 --- newlib/libc/include/sys/cdefs.h | 2 ++ 1 file changed, 2 insertions(+) diff --git a/newlib/libc/include/sys/cdefs.h b/newlib/libc/include/sys/cd= efs.h index 1be994ffd..da7290921 100644 --- a/newlib/libc/include/sys/cdefs.h +++ b/newlib/libc/include/sys/cdefs.h @@ -716,8 +716,10 @@ */ #if __has_attribute(no_sanitize) && defined(__clang__) #define __nosanitizeaddress __attribute__((no_sanitize("address"))) +#define __nosanitizethread __attribute__((no_sanitize("thread"))) #else #define __nosanitizeaddress +#define __nosanitizethread #endif =20 /* Guard variables and structure members by lock. */ --=20 2.26.2