From nobody Mon Feb 9 16:34:13 2026 Delivered-To: importer@patchew.org Received-SPF: pass (zohomail.com: domain of lists.xenproject.org designates 192.237.175.120 as permitted sender) client-ip=192.237.175.120; envelope-from=xen-devel-bounces@lists.xenproject.org; helo=lists.xenproject.org; Authentication-Results: mx.zohomail.com; spf=pass (zohomail.com: domain of lists.xenproject.org designates 192.237.175.120 as permitted sender) smtp.mailfrom=xen-devel-bounces@lists.xenproject.org; dmarc=fail(p=none dis=none) header.from=arm.com Return-Path: Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) by mx.zohomail.com with SMTPS id 1653966841023603.266143373309; Mon, 30 May 2022 20:14:01 -0700 (PDT) Received: from list by lists.xenproject.org with outflank-mailman.338986.563836 (Exim 4.92) (envelope-from ) id 1nvsK7-0005BS-Ub; Tue, 31 May 2022 03:13:35 +0000 Received: by outflank-mailman (output) from mailman id 338986.563836; Tue, 31 May 2022 03:13:35 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1nvsK7-0005BL-RY; Tue, 31 May 2022 03:13:35 +0000 Received: by outflank-mailman (input) for mailman id 338986; Tue, 31 May 2022 03:13:34 +0000 Received: from se1-gles-flk1-in.inumbo.com ([94.247.172.50] helo=se1-gles-flk1.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1nvsK6-0004Go-JT for xen-devel@lists.xenproject.org; Tue, 31 May 2022 03:13:34 +0000 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by se1-gles-flk1.inumbo.com (Halon) with ESMTP id a77049b0-e08f-11ec-837f-e5687231ffcc; Tue, 31 May 2022 05:13:33 +0200 (CEST) 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 3432723A; Mon, 30 May 2022 20:13:33 -0700 (PDT) Received: from a011292.shanghai.arm.com (a011292.shanghai.arm.com [10.169.190.94]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id D3D5E3F66F; Mon, 30 May 2022 20:13:29 -0700 (PDT) X-Outflank-Mailman: Message body and most headers restored to incoming version 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: a77049b0-e08f-11ec-837f-e5687231ffcc From: Penny Zheng To: xen-devel@lists.xenproject.org Cc: wei.chen@arm.com, Penny Zheng , Andrew Cooper , George Dunlap , Jan Beulich , Julien Grall , Stefano Stabellini , Wei Liu , Julien Grall , Penny Zheng Subject: [PATCH v5 4/9] xen: do not merge reserved pages in free_heap_pages() Date: Tue, 31 May 2022 11:12:36 +0800 Message-Id: <20220531031241.90374-5-Penny.Zheng@arm.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20220531031241.90374-1-Penny.Zheng@arm.com> References: <20220531031241.90374-1-Penny.Zheng@arm.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-ZM-MESSAGEID: 1653966841903100008 Content-Type: text/plain; charset="utf-8" The code in free_heap_pages() will try to merge pages with the successor/predecessor if pages are suitably aligned. So if the pages reserved are right next to the pages given to the heap allocator, free_heap_pages() will merge them, and give the reserved pages to heap allocator accidently as a result. So in order to avoid the above scenario, this commit updates free_heap_page= s() to check whether the predecessor and/or successor has PGC_reserved set, when trying to merge the about-to-be-freed chunk with the predecessor and/or successor. Suggested-by: Julien Grall Signed-off-by: Penny Zheng Reviewed-by: Jan Beulich Reviewed-by: Julien Grall --- v5 changes: - change PGC_reserved to adapt to PGC_staticmem --- v4 changes: - no changes --- v3 changes: - no changes --- v2 changes: - new commit --- xen/common/page_alloc.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/xen/common/page_alloc.c b/xen/common/page_alloc.c index 6425761116..b1350fc238 100644 --- a/xen/common/page_alloc.c +++ b/xen/common/page_alloc.c @@ -1482,6 +1482,7 @@ static void free_heap_pages( /* Merge with predecessor block? */ if ( !mfn_valid(page_to_mfn(predecessor)) || !page_state_is(predecessor, free) || + (predecessor->count_info & PGC_staticmem) || (PFN_ORDER(predecessor) !=3D order) || (phys_to_nid(page_to_maddr(predecessor)) !=3D node) ) break; @@ -1505,6 +1506,7 @@ static void free_heap_pages( /* Merge with successor block? */ if ( !mfn_valid(page_to_mfn(successor)) || !page_state_is(successor, free) || + (successor->count_info & PGC_staticmem) || (PFN_ORDER(successor) !=3D order) || (phys_to_nid(page_to_maddr(successor)) !=3D node) ) break; --=20 2.25.1