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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id CC2ECC7618A for ; Wed, 15 Mar 2023 12:31:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232449AbjCOMbj (ORCPT ); Wed, 15 Mar 2023 08:31:39 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40976 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232527AbjCOMbW (ORCPT ); Wed, 15 Mar 2023 08:31:22 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 673376BDE2 for ; Wed, 15 Mar 2023 05:30:27 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 0295C61D26 for ; Wed, 15 Mar 2023 12:30:27 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1AA98C433EF; Wed, 15 Mar 2023 12:30:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1678883426; bh=sVH2vsIk/sno9MnNFLS6rc3jeKS1wSCfh1TDNxfxzF0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=u21dTzGzIUzAbNAZjzjphus0ELzahMOqiqMkhXecRKfncgvvbXth3XFzCUZJsbml2 kPZ4FZqrSwWnX+qc8oSyePoIOmJAB9Zso6qZRWgn08n8QOfniTuE45yORJDxgulYfS Z7P1wwF9pChIscAd+z3cLOJr9wxAiCmwxbk1wYqM= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Rohan McLure , Michael Ellerman , Sasha Levin Subject: [PATCH 5.15 109/145] powerpc/kcsan: Exclude udelay to prevent recursive instrumentation Date: Wed, 15 Mar 2023 13:12:55 +0100 Message-Id: <20230315115742.567863378@linuxfoundation.org> X-Mailer: git-send-email 2.40.0 In-Reply-To: <20230315115738.951067403@linuxfoundation.org> References: <20230315115738.951067403@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Rohan McLure [ Upstream commit 2a7ce82dc46c591c9244057d89a6591c9639b9b9 ] In order for KCSAN to increase its likelihood of observing a data race, it sets a watchpoint on memory accesses and stalls, allowing for detection of conflicting accesses by other kernel threads or interrupts. Stalls are implemented by injecting a call to udelay in instrumented code. To prevent recursive instrumentation, exclude udelay from being instrumented. Signed-off-by: Rohan McLure Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20230206021801.105268-3-rmclure@linux.ibm.com Signed-off-by: Sasha Levin --- arch/powerpc/kernel/time.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/powerpc/kernel/time.c b/arch/powerpc/kernel/time.c index 934d8ae66cc63..4406d7a89558b 100644 --- a/arch/powerpc/kernel/time.c +++ b/arch/powerpc/kernel/time.c @@ -450,7 +450,7 @@ void vtime_flush(struct task_struct *tsk) #define calc_cputime_factors() #endif -void __delay(unsigned long loops) +void __no_kcsan __delay(unsigned long loops) { unsigned long start; @@ -471,7 +471,7 @@ void __delay(unsigned long loops) } EXPORT_SYMBOL(__delay); -void udelay(unsigned long usecs) +void __no_kcsan udelay(unsigned long usecs) { __delay(tb_ticks_per_usec * usecs); } -- 2.39.2