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=-12.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,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 7D23EC43460 for ; Wed, 31 Mar 2021 13:52:53 +0000 (UTC) Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (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 3133A600D1 for ; Wed, 31 Mar 2021 13:52:53 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3133A600D1 Authentication-Results: mail.kernel.org; dmarc=fail (p=quarantine dis=none) header.from=suse.com Authentication-Results: mail.kernel.org; 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Wed, 31 Mar 2021 13:52:42 +0000 (UTC) Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 662F2B288; Wed, 31 Mar 2021 13:52:41 +0000 (UTC) X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: d24f7b25-4a52-4318-a3fc-ea577d4bd3cf X-Virus-Scanned: by amavisd-new at test-mx.suse.de DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1617198761; h=from:from:reply-to: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=yKknCWV6+9pJC7xqpVlz2vjQm1QbRp0EQF62y/4fyuw=; b=JJMUgnCENn62x+WwJQ57GVFhsFzqtthfcoo3BqPj8emLHIzwLHzs0I1u+V0SIWy3BtTgH3 0+uG05wuudRUClA5x2knRiqFU7z9gaE/wunXLqxlS3KPTJg9R/IhdQjjWsirTpmH0+TCX6 jOqhbms24jzBkPk2swGenWbZRkw8/OE= Subject: Re: [PATCH] x86/hvm: Fix double free from vlapic_init() early error path To: =?UTF-8?Q?Roger_Pau_Monn=c3=a9?= Cc: Xen-devel , Wei Liu , Andrew Cooper References: <20210331133125.7072-1-andrew.cooper3@citrix.com> From: Jan Beulich Message-ID: <4679a1fb-2935-1cda-acb6-429e783248d4@suse.com> Date: Wed, 31 Mar 2021 15:52:40 +0200 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.9.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit On 31.03.2021 15:49, Roger Pau Monné wrote: > On Wed, Mar 31, 2021 at 02:31:25PM +0100, Andrew Cooper wrote: >> @@ -1645,8 +1642,8 @@ void vlapic_destroy(struct vcpu *v) >> tasklet_kill(&vlapic->init_sipi.tasklet); >> TRACE_0D(TRC_HVM_EMUL_LAPIC_STOP_TIMER); >> destroy_periodic_time(&vlapic->pt); >> - unmap_domain_page_global(vlapic->regs); >> - free_domheap_page(vlapic->regs_page); >> + UNMAP_DOMAIN_PAGE_GLOBAL(vlapic->regs); > > I think you need to check whether vlapic->regs_page is NULL here... > >> + FREE_DOMHEAP_PAGE(vlapic->regs_page); >> } >> >> /* >> diff --git a/xen/include/xen/domain_page.h b/xen/include/xen/domain_page.h >> index a182d33b67..0cb7f2aad3 100644 >> --- a/xen/include/xen/domain_page.h >> +++ b/xen/include/xen/domain_page.h >> @@ -77,4 +77,9 @@ static inline void unmap_domain_page_global(const void *va) {}; >> (p) = NULL; \ >> } while ( false ) >> >> +#define UNMAP_DOMAIN_PAGE_GLOBAL(p) do { \ >> + unmap_domain_page_global(p); \ >> + (p) = NULL; \ >> +} while ( false ) >> + >> #endif /* __XEN_DOMAIN_PAGE_H__ */ >> diff --git a/xen/include/xen/mm.h b/xen/include/xen/mm.h >> index 667f9dac83..c274e2eac4 100644 >> --- a/xen/include/xen/mm.h >> +++ b/xen/include/xen/mm.h >> @@ -85,6 +85,12 @@ bool scrub_free_pages(void); >> } while ( false ) >> #define FREE_XENHEAP_PAGE(p) FREE_XENHEAP_PAGES(p, 0) >> >> +#define FREE_DOMHEAP_PAGES(p, o) do { \ >> + free_domheap_pages(p, o); \ > > ...as both unmap_domain_page_global and free_domheap_pages don't > support being passed a NULL pointer. Except that such checking would better go into the new macros, alongside their clearing the pointers afterwards. Jan