From patchwork Mon May 17 14:02:11 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 440134 Delivered-To: patch@linaro.org Received: by 2002:a02:7a1b:0:0:0:0:0 with SMTP id a27csp1203318jac; Mon, 17 May 2021 08:42:33 -0700 (PDT) X-Google-Smtp-Source: ABdhPJwNhYBCmUM+CTNwy59t9DDeh1n6lZ0LBx7EQZZDAcFbg3A4LCfgEp+WH6b+nOKwijEvzeWK X-Received: by 2002:a9d:243:: with SMTP id 61mr146325otb.267.1621266153078; Mon, 17 May 2021 08:42:33 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1621266153; cv=none; d=google.com; s=arc-20160816; b=S8nGmOhvdfZeDBPlt5Uo1rNwwBoEVj3aPb4vkcgYWtWZTXNz58aBXSVjxfjHIOu7Xf eK/4rN0h6tKWCS/tEvHiknxF79ojOua2z5zGkpzYJjTfFgyK+tOHDtT0zrWzODE3TVLG ClpKskdhgtrXZVZR+BzylInLYFUS8TVyGOFWDNSRYCIBRADC7AbI/g+lk2lvc09QoosO JHq9XOgD75J5MsjvWega9dOGIpotcr2WLdtH/AcCCpk4lxtNt8VgO1jhpYfs3641msYj OeKq12fdwSTQsPj9b2TTNIfvkkSGCLN1JjXUmjd1cyIdswlKheqlLSzpsZkbgKcbXiDC lHWQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:content-transfer-encoding:mime-version :user-agent:references:in-reply-to:message-id:date:subject:cc:to :from:dkim-signature; bh=hzrl4z2QMxvZCTonFqYi0sIC+xfYQC5jGAjMPf72fo4=; b=tbqm27qXajTPrMURBllp8CzOTcIb3whXkDH3NFNZrXp4Y9P1bTx6hWLqoqv9ML9irB 8M8r94klTTSOJ6IUJZbUQgfwlfomYeryfW87FEFJs3jcK2bTh7yJMYiX1IJJGntmA7vm c21OWzmvQf9noYBUkws6831vpYyWbcS2VZzjjuo/Rj5TziBokFQe8WXk1FZftQi3ek+v tkynt3RYlY5U/EKhf6rTHYsJeu2uNnmXxt5L4scw220yk7kHPgW+yQ/+7rueNZx5Tn4n loznznFesXB0Ib7zTGQ4f77jboXR9ZFUrisGQ8K/ZYYjwmEG5LT1Tbof7c1sr5zFQwWM ylww== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@linuxfoundation.org header.s=korg header.b=IW2YTMMD; spf=pass (google.com: domain of stable-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=stable-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=linuxfoundation.org Return-Path: Received: from vger.kernel.org (vger.kernel.org. [23.128.96.18]) by mx.google.com with ESMTP id o18si16514808otk.241.2021.05.17.08.42.32; Mon, 17 May 2021 08:42:33 -0700 (PDT) Received-SPF: pass (google.com: domain of stable-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; dkim=pass header.i=@linuxfoundation.org header.s=korg header.b=IW2YTMMD; spf=pass (google.com: domain of stable-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=stable-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=linuxfoundation.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S245494AbhEQPnk (ORCPT + 12 others); Mon, 17 May 2021 11:43:40 -0400 Received: from mail.kernel.org ([198.145.29.99]:51344 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239015AbhEQPlg (ORCPT ); Mon, 17 May 2021 11:41:36 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 7584561D13; Mon, 17 May 2021 14:42:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1621262522; bh=pnKSpHyz9pQmxPkhijylRsJgz8hvUcVRIQ3sz0mB/KM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=IW2YTMMDpi5WF1u1ess6nff4NKml2BOpOmtzjQWO2+ZeoQ9KzniG/97jAVZb7OCXN eAvtSPY6HHMqex8CIlT5XLp/1ipY4ybbHNihwJDFDsgbtcdem/Iker+CKf3cxzlygk Rcll5FVPjfcC944xVC8MSSbnGbKmIXOPiDtLMQtY= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Catalin Marinas , Will Deacon , Steven Price Subject: [PATCH 5.10 206/289] arm64: Fix race condition on PG_dcache_clean in __sync_icache_dcache() Date: Mon, 17 May 2021 16:02:11 +0200 Message-Id: <20210517140312.047235100@linuxfoundation.org> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210517140305.140529752@linuxfoundation.org> References: <20210517140305.140529752@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Catalin Marinas commit 588a513d34257fdde95a9f0df0202e31998e85c6 upstream. To ensure that instructions are observable in a new mapping, the arm64 set_pte_at() implementation cleans the D-cache and invalidates the I-cache to the PoU. As an optimisation, this is only done on executable mappings and the PG_dcache_clean page flag is set to avoid future cache maintenance on the same page. When two different processes map the same page (e.g. private executable file or shared mapping) there's a potential race on checking and setting PG_dcache_clean via set_pte_at() -> __sync_icache_dcache(). While on the fault paths the page is locked (PG_locked), mprotect() does not take the page lock. The result is that one process may see the PG_dcache_clean flag set but the I/D cache maintenance not yet performed. Avoid test_and_set_bit(PG_dcache_clean) in favour of separate test_bit() and set_bit(). In the rare event of a race, the cache maintenance is done twice. Signed-off-by: Catalin Marinas Cc: Cc: Will Deacon Cc: Steven Price Reviewed-by: Steven Price Acked-by: Will Deacon Link: https://lore.kernel.org/r/20210514095001.13236-1-catalin.marinas@arm.com Signed-off-by: Catalin Marinas Signed-off-by: Greg Kroah-Hartman --- arch/arm64/mm/flush.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) --- a/arch/arm64/mm/flush.c +++ b/arch/arm64/mm/flush.c @@ -55,8 +55,10 @@ void __sync_icache_dcache(pte_t pte) { struct page *page = pte_page(pte); - if (!test_and_set_bit(PG_dcache_clean, &page->flags)) + if (!test_bit(PG_dcache_clean, &page->flags)) { sync_icache_aliases(page_address(page), page_size(page)); + set_bit(PG_dcache_clean, &page->flags); + } } EXPORT_SYMBOL_GPL(__sync_icache_dcache);