From patchwork Wed Jun 9 14:46:47 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: thermal-bot for Julien Panis X-Patchwork-Id: 458488 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=-20.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING, SPF_HELO_NONE, SPF_PASS 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 2F7DBC48BCF for ; Wed, 9 Jun 2021 14:46:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1EFE9613AD for ; Wed, 9 Jun 2021 14:46:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238162AbhFIOsq (ORCPT ); Wed, 9 Jun 2021 10:48:46 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42624 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238122AbhFIOsp (ORCPT ); Wed, 9 Jun 2021 10:48:45 -0400 Received: from galois.linutronix.de (Galois.linutronix.de [IPv6:2a0a:51c0:0:12e:550::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 102F8C061574; Wed, 9 Jun 2021 07:46:49 -0700 (PDT) Date: Wed, 09 Jun 2021 14:46:47 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1623250008; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=Nswt7SFOeTd1iTSFLSagR0Vwg3s8VW3bWmaxFkE410A=; b=vMAik4xkcfcV4jnGJ70i1AK7Cdym2GFu31vQOhLp1JL+zuXyOJ1clFfZz5e4KDHrUyJJfU zEJARMxs3CEHN/TswXCxijsT4eSCjMoktDQHSGk3RFSMIY02lujKzSwG16WqYQ883At2OP /1+WIYc8drmF6KlDH4z46xNlY5F+k2698agnKEmFIMS2a2KdfwVjJYHsbCjAHErwiRO5Py WTnBw97KyJtCre5QJnFHuOok3Y8Z7ugu15vjowgAZIEelGueowZSOztCRbElpB5PcoE5cv clw3ORt1BZmh1Pp4IB2EvHANIPbt0orfYzB2cOx2iBAx/fit2USrAwDykQkuYQ== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1623250008; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=Nswt7SFOeTd1iTSFLSagR0Vwg3s8VW3bWmaxFkE410A=; b=IzOhMWLhI1he2I2de3cwtOnZ2GGviQlZwI/e6di/j8Cma0aIcbJHj6pfYsgCErIY1ohdIn jiRW5GonwPEy9yBg== From: "tip-bot2 for Thomas Gleixner" Sender: tip-bot2@linutronix.de Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: x86/urgent] x86/process: Check PF_KTHREAD and not current->mm for kernel threads Cc: Thomas Gleixner , Borislav Petkov , Dave Hansen , Rik van Riel , stable@vger.kernel.org, x86@kernel.org, linux-kernel@vger.kernel.org In-Reply-To: <20210608144345.912645927@linutronix.de> References: <20210608144345.912645927@linutronix.de> MIME-Version: 1.0 Message-ID: <162325000736.29796.12036319105894610527.tip-bot2@tip-bot2> Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org The following commit has been merged into the x86/urgent branch of tip: Commit-ID: 12f7764ac61200e32c916f038bdc08f884b0b604 Gitweb: https://git.kernel.org/tip/12f7764ac61200e32c916f038bdc08f884b0b604 Author: Thomas Gleixner AuthorDate: Tue, 08 Jun 2021 16:36:20 +02:00 Committer: Borislav Petkov CommitterDate: Wed, 09 Jun 2021 10:39:04 +02:00 x86/process: Check PF_KTHREAD and not current->mm for kernel threads switch_fpu_finish() checks current->mm as indicator for kernel threads. That's wrong because kernel threads can temporarily use a mm of a user process via kthread_use_mm(). Check the task flags for PF_KTHREAD instead. Fixes: 0cecca9d03c9 ("x86/fpu: Eager switch PKRU state") Signed-off-by: Thomas Gleixner Signed-off-by: Borislav Petkov Acked-by: Dave Hansen Acked-by: Rik van Riel Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/20210608144345.912645927@linutronix.de --- arch/x86/include/asm/fpu/internal.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/include/asm/fpu/internal.h b/arch/x86/include/asm/fpu/internal.h index ceeba9f..18382ac 100644 --- a/arch/x86/include/asm/fpu/internal.h +++ b/arch/x86/include/asm/fpu/internal.h @@ -578,7 +578,7 @@ static inline void switch_fpu_finish(struct fpu *new_fpu) * PKRU state is switched eagerly because it needs to be valid before we * return to userland e.g. for a copy_to_user() operation. */ - if (current->mm) { + if (!(current->flags & PF_KTHREAD)) { pk = get_xsave_addr(&new_fpu->state.xsave, XFEATURE_PKRU); if (pk) pkru_val = pk->pkru;