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=-8.3 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 4992FC2BA19 for ; Tue, 14 Apr 2020 12:50:00 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 1CCBD2076B for ; Tue, 14 Apr 2020 12:50:00 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="snAqYJ4/" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1CCBD2076B Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:Date: Message-ID:From:References:To:Subject:Reply-To:Content-ID:Content-Description :Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=g9fRh3Tu4AjSuTiIjIeKbtdNfg3YsTdIhwU8WtiMaSM=; b=snAqYJ4/ADSVIH VrJ2S4mVl61UlctABsdfmniRwXQzo/+kdP4Bo3c5rnMBz3gw1Lw4gJM9g42yrHeoo5c30Mnn5umGN sgK9JGESiVYL7otmFxebmeT8giUQ8wfCi5FLWVuBoCg2KfU5U2I/rvOtWg/A7k1NwkgyDyBsielX4 fDoB5tCN0KIoMTc7y9viZgMnvwbF4zfA0H9MRMyXrTrG4JkQqkYcJmLn/2Q/jl6eeEs6Xu+0m6lyZ A11a8C5IsGMdcu6G5xWZq+JYT4tjpKmrl8ksCLoMWraJJTbmDyJjQDz2uhCMDptXgj3MV6Yx6FOrg U4QvOuAQSQCR9spxa7mg==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1jOL0p-0003B4-BI; Tue, 14 Apr 2020 12:49:59 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1jOL0i-00034d-4X for linux-arm-kernel@lists.infradead.org; Tue, 14 Apr 2020 12:49:53 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 637941FB; Tue, 14 Apr 2020 05:49:51 -0700 (PDT) Received: from [192.168.1.172] (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 568493F73D; Tue, 14 Apr 2020 05:49:50 -0700 (PDT) Subject: Re: [PATCH 1/5] arm64: vdso: don't free unallocated pages To: Mark Rutland , linux-arm-kernel@lists.infradead.org References: <20200414104252.16061-1-mark.rutland@arm.com> <20200414104252.16061-2-mark.rutland@arm.com> From: Vincenzo Frascino Message-ID: Date: Tue, 14 Apr 2020 13:50:38 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.9.0 MIME-Version: 1.0 In-Reply-To: <20200414104252.16061-2-mark.rutland@arm.com> Content-Language: en-US X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200414_054952_233623_C616110C X-CRM114-Status: GOOD ( 20.12 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: catalin.marinas@arm.com, will@kernel.org, stable@vger.kernel.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org Hi Mark, On 4/14/20 11:42 AM, Mark Rutland wrote: > The aarch32_vdso_pages[] array never has entries allocated in the C_VVAR > or C_VDSO slots, and as the array is zero initialized these contain > NULL. > > However in __aarch32_alloc_vdso_pages() when > aarch32_alloc_kuser_vdso_page() fails we attempt to free the page whose > struct page is at NULL, which is obviously nonsensical. > Could you please explain why do you think that free(NULL) is "nonsensical"? And if this is causing a bug (according to the cover-letter), could you please provide a stack-trace? > This patch removes the erroneous page freeing. > > Signed-off-by: Mark Rutland > Cc: Catalin Marinas > Cc: Vincenzo Frascino > Cc: Will Deacon > Cc: stable@vger.kernel.org > --- > arch/arm64/kernel/vdso.c | 13 +------------ > 1 file changed, 1 insertion(+), 12 deletions(-) > > diff --git a/arch/arm64/kernel/vdso.c b/arch/arm64/kernel/vdso.c > index 354b11e27c07..033a48f30dbb 100644 > --- a/arch/arm64/kernel/vdso.c > +++ b/arch/arm64/kernel/vdso.c > @@ -260,18 +260,7 @@ static int __aarch32_alloc_vdso_pages(void) > if (ret) > return ret; > > - ret = aarch32_alloc_kuser_vdso_page(); > - if (ret) { > - unsigned long c_vvar = > - (unsigned long)page_to_virt(aarch32_vdso_pages[C_VVAR]); > - unsigned long c_vdso = > - (unsigned long)page_to_virt(aarch32_vdso_pages[C_VDSO]); > - > - free_page(c_vvar); > - free_page(c_vdso); > - } > - > - return ret; > + return aarch32_alloc_kuser_vdso_page(); > } > #else > static int __aarch32_alloc_vdso_pages(void) > -- Regards, Vincenzo _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel