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=-11.8 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 551CEC433E1 for ; Tue, 19 May 2020 19:58:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3C980214D8 for ; Tue, 19 May 2020 19:58:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728244AbgEST6w (ORCPT ); Tue, 19 May 2020 15:58:52 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51980 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728085AbgEST6k (ORCPT ); Tue, 19 May 2020 15:58:40 -0400 Received: from Galois.linutronix.de (Galois.linutronix.de [IPv6:2a0a:51c0:0:12e:550::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1387AC08C5C0; Tue, 19 May 2020 12:58:40 -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 1jb8Nm-0008Gz-Qr; Tue, 19 May 2020 21:58:35 +0200 Received: from [127.0.1.1] (localhost [IPv6:::1]) by tip-bot2.lab.linutronix.de (Postfix) with ESMTP id 2CCF71C0178; Tue, 19 May 2020 21:58:27 +0200 (CEST) Date: Tue, 19 May 2020 19:58:27 -0000 From: "tip-bot2 for Peter Zijlstra" Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: x86/entry] x86/int3: Avoid atomic instrumentation Cc: Thomas Gleixner , "Peter Zijlstra (Intel)" , Masami Hiramatsu , Alexandre Chartre , Andy Lutomirski , x86 , LKML In-Reply-To: <20200505135313.517429268@linutronix.de> References: <20200505135313.517429268@linutronix.de> MIME-Version: 1.0 Message-ID: <158991830703.17951.7301728008554770838.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 x86/entry branch of tip: Commit-ID: a53a1d0435cdc2b66f41f75fa1cee31e8fe6d99e Gitweb: https://git.kernel.org/tip/a53a1d0435cdc2b66f41f75fa1cee31e8fe6d99e Author: Peter Zijlstra AuthorDate: Fri, 24 Jan 2020 22:08:45 +01:00 Committer: Thomas Gleixner CommitterDate: Tue, 19 May 2020 16:04:05 +02:00 x86/int3: Avoid atomic instrumentation Use arch_atomic_*() and __READ_ONCE() to ensure nothing untoward creeps in and ruins things. That is; this is the INT3 text poke handler, strictly limit the code that runs in it, lest it inadvertenly hits yet another INT3. Reported-by: Thomas Gleixner Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Thomas Gleixner Reviewed-by: Masami Hiramatsu Reviewed-by: Alexandre Chartre Acked-by: Andy Lutomirski Link: https://lkml.kernel.org/r/20200505135313.517429268@linutronix.de --- arch/x86/kernel/alternative.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c index 1f4cb2c..686c8ac 100644 --- a/arch/x86/kernel/alternative.c +++ b/arch/x86/kernel/alternative.c @@ -960,9 +960,9 @@ static struct bp_patching_desc *bp_desc; static __always_inline struct bp_patching_desc *try_get_desc(struct bp_patching_desc **descp) { - struct bp_patching_desc *desc = READ_ONCE(*descp); /* rcu_dereference */ + struct bp_patching_desc *desc = __READ_ONCE(*descp); /* rcu_dereference */ - if (!desc || !atomic_inc_not_zero(&desc->refs)) + if (!desc || !arch_atomic_inc_not_zero(&desc->refs)) return NULL; return desc; @@ -971,7 +971,7 @@ struct bp_patching_desc *try_get_desc(struct bp_patching_desc **descp) static __always_inline void put_desc(struct bp_patching_desc *desc) { smp_mb__before_atomic(); - atomic_dec(&desc->refs); + arch_atomic_dec(&desc->refs); } static __always_inline void *text_poke_addr(struct text_poke_loc *tp)