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=-11.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 A5936C54E4A for ; Tue, 12 May 2020 14:37:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8D7A9206F5 for ; Tue, 12 May 2020 14:37:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730511AbgELOht (ORCPT ); Tue, 12 May 2020 10:37:49 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39396 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730390AbgELOhH (ORCPT ); Tue, 12 May 2020 10:37:07 -0400 Received: from Galois.linutronix.de (Galois.linutronix.de [IPv6:2a0a:51c0:0:12e:550::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D7BADC061A0C; Tue, 12 May 2020 07:37:06 -0700 (PDT) Received: from [5.158.153.53] (helo=tip-bot2.lab.linutronix.de) by Galois.linutronix.de with esmtpsa (TLS1.2:DHE_RSA_AES_256_CBC_SHA256:256) (Exim 4.80) (envelope-from ) id 1jYW1m-0005oT-Hm; Tue, 12 May 2020 16:37:02 +0200 Received: from [127.0.1.1] (localhost [IPv6:::1]) by tip-bot2.lab.linutronix.de (Postfix) with ESMTP id 28DED1C02FC; Tue, 12 May 2020 16:36:57 +0200 (CEST) Date: Tue, 12 May 2020 14:36:57 -0000 From: "tip-bot2 for Will Deacon" Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: locking/kcsan] arm64: csum: Disable KASAN for do_csum() Cc: Will Deacon , Thomas Gleixner , "Peter Zijlstra (Intel)" , Robin Murphy , Mark Rutland , x86 , LKML In-Reply-To: <20200511204150.27858-10-will@kernel.org> References: <20200511204150.27858-10-will@kernel.org> MIME-Version: 1.0 Message-ID: <158929421706.390.7180347611312601499.tip-bot2@tip-bot2> X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1,SHORTCIRCUIT=-0.0001 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The following commit has been merged into the locking/kcsan branch of tip: Commit-ID: 5a7d7f5d57f61d650619b89c1b7d4adcf4fdecfe Gitweb: https://git.kernel.org/tip/5a7d7f5d57f61d650619b89c1b7d4adcf4fdecfe Author: Will Deacon AuthorDate: Mon, 11 May 2020 21:41:41 +01:00 Committer: Thomas Gleixner CommitterDate: Tue, 12 May 2020 11:04:13 +02:00 arm64: csum: Disable KASAN for do_csum() do_csum() over-reads the source buffer and therefore abuses READ_ONCE_NOCHECK() on a 128-bit type to avoid tripping up KASAN. In preparation for READ_ONCE_NOCHECK() requiring an atomic access, and therefore failing to build when fed a '__uint128_t', annotate do_csum() explicitly with '__no_sanitize_address' and fall back to normal loads. Signed-off-by: Will Deacon Signed-off-by: Thomas Gleixner Acked-by: Peter Zijlstra (Intel) Acked-by: Robin Murphy Acked-by: Mark Rutland Link: https://lkml.kernel.org/r/20200511204150.27858-10-will@kernel.org --- arch/arm64/lib/csum.c | 20 ++++++++++++-------- 1 file changed, 12 insertions(+), 8 deletions(-) diff --git a/arch/arm64/lib/csum.c b/arch/arm64/lib/csum.c index 60eccae..78b87a6 100644 --- a/arch/arm64/lib/csum.c +++ b/arch/arm64/lib/csum.c @@ -14,7 +14,11 @@ static u64 accumulate(u64 sum, u64 data) return tmp + (tmp >> 64); } -unsigned int do_csum(const unsigned char *buff, int len) +/* + * We over-read the buffer and this makes KASAN unhappy. Instead, disable + * instrumentation and call kasan explicitly. + */ +unsigned int __no_sanitize_address do_csum(const unsigned char *buff, int len) { unsigned int offset, shift, sum; const u64 *ptr; @@ -42,7 +46,7 @@ unsigned int do_csum(const unsigned char *buff, int len) * odd/even alignment, and means we can ignore it until the very end. */ shift = offset * 8; - data = READ_ONCE_NOCHECK(*ptr++); + data = *ptr++; #ifdef __LITTLE_ENDIAN data = (data >> shift) << shift; #else @@ -58,10 +62,10 @@ unsigned int do_csum(const unsigned char *buff, int len) while (unlikely(len > 64)) { __uint128_t tmp1, tmp2, tmp3, tmp4; - tmp1 = READ_ONCE_NOCHECK(*(__uint128_t *)ptr); - tmp2 = READ_ONCE_NOCHECK(*(__uint128_t *)(ptr + 2)); - tmp3 = READ_ONCE_NOCHECK(*(__uint128_t *)(ptr + 4)); - tmp4 = READ_ONCE_NOCHECK(*(__uint128_t *)(ptr + 6)); + tmp1 = *(__uint128_t *)ptr; + tmp2 = *(__uint128_t *)(ptr + 2); + tmp3 = *(__uint128_t *)(ptr + 4); + tmp4 = *(__uint128_t *)(ptr + 6); len -= 64; ptr += 8; @@ -85,7 +89,7 @@ unsigned int do_csum(const unsigned char *buff, int len) __uint128_t tmp; sum64 = accumulate(sum64, data); - tmp = READ_ONCE_NOCHECK(*(__uint128_t *)ptr); + tmp = *(__uint128_t *)ptr; len -= 16; ptr += 2; @@ -100,7 +104,7 @@ unsigned int do_csum(const unsigned char *buff, int len) } if (len > 0) { sum64 = accumulate(sum64, data); - data = READ_ONCE_NOCHECK(*ptr); + data = *ptr; len -= 8; } /*