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=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,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 46515C31E45 for ; Thu, 13 Jun 2019 19:08:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1E2EA21721 for ; Thu, 13 Jun 2019 19:08:35 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=zytor.com header.i=@zytor.com header.b="MLGchTjn" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728887AbfFMTId (ORCPT ); Thu, 13 Jun 2019 15:08:33 -0400 Received: from terminus.zytor.com ([198.137.202.136]:55765 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725842AbfFMTId (ORCPT ); Thu, 13 Jun 2019 15:08:33 -0400 Received: from terminus.zytor.com (localhost [127.0.0.1]) by terminus.zytor.com (8.15.2/8.15.2) with ESMTPS id x5DJ7DmZ1314171 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NO); Thu, 13 Jun 2019 12:07:13 -0700 DKIM-Filter: OpenDKIM Filter v2.11.0 terminus.zytor.com x5DJ7DmZ1314171 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=zytor.com; s=2019051801; t=1560452834; bh=agiqwfohILXjIImlF3CLGf5swTtJl1GxmhuS2kIPfEI=; h=Date:From:Cc:Reply-To:In-Reply-To:References:To:Subject:From; b=MLGchTjn5cspHXoUZ6XRKkwn7NiVjtKWQIqPuvmN4svsovldsNVyiwcVqk26uDl39 y0V9nab27SLfXRWcBt5t65k8pfEsgmqTlavw7pCg8hYUOA7ICGjwjatTcH76u7GGpZ KLhI4fExnY606XyMA7bQD/5zyHrTiOoKd65dXBaZtY+pUxPwJuVB/6LGEj2McTMmpf jnlVJUmpRxWRFfFgJJ/o2hMHSgtqpyU4jxnDTR0i1+u+FvY9gdY6Zk5H7fPoLTJHKV 7HJDTXh2xherMPQpWgXKHolVYfRbeZOMdfKd+lRH3E4HdNxDb+uKKN2sC0LlwIWaxO DNz0+3X4Ik8ig== Received: (from tipbot@localhost) by terminus.zytor.com (8.15.2/8.15.2/Submit) id x5DJ7D2p1314168; Thu, 13 Jun 2019 12:07:13 -0700 Date: Thu, 13 Jun 2019 12:07:13 -0700 X-Authentication-Warning: terminus.zytor.com: tipbot set sender to tipbot@zytor.com using -f From: tip-bot for Christoph Hellwig Message-ID: Cc: bigeasy@linutronix.de, hch@lst.de, jannh@google.com, bp@suse.de, mingo@redhat.com, aubrey.li@intel.com, dave.hansen@intel.com, linux-kernel@vger.kernel.org, hpa@zytor.com, x86@kernel.org, tglx@linutronix.de, riel@surriel.com, mingo@kernel.org, nstange@suse.de, peterz@infradead.org Reply-To: tglx@linutronix.de, riel@surriel.com, x86@kernel.org, nstange@suse.de, mingo@kernel.org, linux-kernel@vger.kernel.org, hpa@zytor.com, peterz@infradead.org, hch@lst.de, jannh@google.com, bp@suse.de, bigeasy@linutronix.de, dave.hansen@intel.com, mingo@redhat.com, aubrey.li@intel.com In-Reply-To: <20190604175411.GA27477@lst.de> References: <20190604175411.GA27477@lst.de> To: linux-tip-commits@vger.kernel.org Subject: [tip:x86/urgent] x86/fpu: Don't use current->mm to check for a kthread Git-Commit-ID: 8d3289f2fa1e0c7e2f72c7352f1efb75d2ad7c76 X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 8d3289f2fa1e0c7e2f72c7352f1efb75d2ad7c76 Gitweb: https://git.kernel.org/tip/8d3289f2fa1e0c7e2f72c7352f1efb75d2ad7c76 Author: Christoph Hellwig AuthorDate: Tue, 4 Jun 2019 19:54:12 +0200 Committer: Borislav Petkov CommitDate: Thu, 13 Jun 2019 20:57:49 +0200 x86/fpu: Don't use current->mm to check for a kthread current->mm can be non-NULL if a kthread calls use_mm(). Check for PF_KTHREAD instead to decide when to store user mode FP state. Fixes: 2722146eb784 ("x86/fpu: Remove fpu->initialized") Reported-by: Peter Zijlstra Signed-off-by: Christoph Hellwig Signed-off-by: Borislav Petkov Acked-by: Sebastian Andrzej Siewior Cc: Aubrey Li Cc: Dave Hansen Cc: "H. Peter Anvin" Cc: Ingo Molnar Cc: Jann Horn Cc: Nicolai Stange Cc: Rik van Riel Cc: Thomas Gleixner Cc: x86-ml Link: https://lkml.kernel.org/r/20190604175411.GA27477@lst.de --- arch/x86/include/asm/fpu/internal.h | 6 +++--- arch/x86/kernel/fpu/core.c | 2 +- 2 files changed, 4 insertions(+), 4 deletions(-) diff --git a/arch/x86/include/asm/fpu/internal.h b/arch/x86/include/asm/fpu/internal.h index 9e27fa05a7ae..4c95c365058a 100644 --- a/arch/x86/include/asm/fpu/internal.h +++ b/arch/x86/include/asm/fpu/internal.h @@ -536,7 +536,7 @@ static inline void __fpregs_load_activate(void) struct fpu *fpu = ¤t->thread.fpu; int cpu = smp_processor_id(); - if (WARN_ON_ONCE(current->mm == NULL)) + if (WARN_ON_ONCE(current->flags & PF_KTHREAD)) return; if (!fpregs_state_valid(fpu, cpu)) { @@ -567,11 +567,11 @@ static inline void __fpregs_load_activate(void) * otherwise. * * The FPU context is only stored/restored for a user task and - * ->mm is used to distinguish between kernel and user threads. + * PF_KTHREAD is used to distinguish between kernel and user threads. */ static inline void switch_fpu_prepare(struct fpu *old_fpu, int cpu) { - if (static_cpu_has(X86_FEATURE_FPU) && current->mm) { + if (static_cpu_has(X86_FEATURE_FPU) && !(current->flags & PF_KTHREAD)) { if (!copy_fpregs_to_fpstate(old_fpu)) old_fpu->last_cpu = -1; else diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c index 466fca686fb9..649fbc3fcf9f 100644 --- a/arch/x86/kernel/fpu/core.c +++ b/arch/x86/kernel/fpu/core.c @@ -102,7 +102,7 @@ static void __kernel_fpu_begin(void) kernel_fpu_disable(); - if (current->mm) { + if (!(current->flags & PF_KTHREAD)) { if (!test_thread_flag(TIF_NEED_FPU_LOAD)) { set_thread_flag(TIF_NEED_FPU_LOAD); /*