From patchwork Mon May 17 14:02:34 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 440131 Delivered-To: patch@linaro.org Received: by 2002:a02:7a1b:0:0:0:0:0 with SMTP id a27csp1192543jac; Mon, 17 May 2021 08:30:13 -0700 (PDT) X-Google-Smtp-Source: ABdhPJxsRfd0+mIcdIWhyHKHoaGSFZMaNRLa03NhdJu++jcQesO20XdPycOaxC1zmoKxz0NS5gkL X-Received: by 2002:a17:906:d1d1:: with SMTP id bs17mr487938ejb.492.1621265413111; Mon, 17 May 2021 08:30:13 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1621265413; cv=none; d=google.com; s=arc-20160816; b=X1stJVu9QFY+CZZ331bAGEGZC5vLcBHeNtiQL/TmfxT5yXd4JwTi2dHy4OfaO9bgSE aJO1dwSlJNb7xiaxBRfo3g8TxwKJKGHtmTmR5Pq87ejCB2YNE/l8Uglm2m+kVqHioYGV a0OsELkMrJg4stV0cN6xa9YzTxNLTfCVyrE6T9La1p8xMRs9zdLj/sqpyum9e+rUIGUY gXZ7KronhOu/e5reHLfiVnkbvJpfHcCZiLVSaGE5Z+SUD1NyPGOo7zul/jQU5h+qwyEN OD2sFdjeIoFK8ytjuveCesmaf/pQKZj9yJ0X/6pyhSmI+gLF/dK3du2A3PNmgl3bjxVE cLMQ== 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=mtqbQyRQ2uztIXMxRZSTeVacKUtzKJIRF2TPNstwUSZLX7+Hp/He9MFRzGT9rFGEOR gavDZ76g1CSqIuzvsy8VzXUxTBdG4yywmD+A8kMYp0m8UyvPB0oC5C5zE7BaEhai4pdr nv73NT+jtEPtNdxn3r3NRrONAP/mAv/rmAvjLinWg4n3YVrg87A03soAKN/2LoLg6yWv Osh4VhjZx+kM5Qi/4Tm5uiv2ypFsucaJ9cxmeBX4oIW2faZuBGnv+86TI/VfzSY6Tkx8 2oqDdbt5yPhaZg8B0egTeEuPRwqoH5tM+SdlLkJHqVqpYaSzbZjlB2AxzZ7Q82rJglHz e/Xg== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@linuxfoundation.org header.s=korg header.b=Nsh5MdNf; 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 w11si17409180ejc.493.2021.05.17.08.30.12; Mon, 17 May 2021 08:30:13 -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=Nsh5MdNf; 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 S244462AbhEQPbR (ORCPT + 12 others); Mon, 17 May 2021 11:31:17 -0400 Received: from mail.kernel.org ([198.145.29.99]:54844 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243767AbhEQP2Z (ORCPT ); Mon, 17 May 2021 11:28:25 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 7433961933; Mon, 17 May 2021 14:37:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1621262227; bh=pnKSpHyz9pQmxPkhijylRsJgz8hvUcVRIQ3sz0mB/KM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Nsh5MdNf9RogIClfpoip5VbljMEXQDw4oa/VQSF+qvtbpzyHmKGM1NocFx5aPEo8E BwTad2+KkJAclFiqs5HXvlEaTzO9XigW5IWdR9Yv4M2Q1Gd3NVq84tK9iynHxjmem9 BnqAf4yP5V+mXa2vSqNArjZSiEa/qA1oaCFMBcVE= 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 5.11 243/329] arm64: Fix race condition on PG_dcache_clean in __sync_icache_dcache() Date: Mon, 17 May 2021 16:02:34 +0200 Message-Id: <20210517140310.330312747@linuxfoundation.org> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210517140302.043055203@linuxfoundation.org> References: <20210517140302.043055203@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);