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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2DD08C77B7A for ; Wed, 31 May 2023 00:14:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233365AbjEaAN7 (ORCPT ); Tue, 30 May 2023 20:13:59 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44964 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229725AbjEaAN4 (ORCPT ); Tue, 30 May 2023 20:13:56 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CA482B2 for ; Tue, 30 May 2023 17:13:09 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1685491988; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=XMlftAvKzPLGRcgmcHupK2Ab5W7s4ldFaTzuXWoZEBE=; b=heQyNnPuQ3MWNFk7qYcBpSVDSIMcKuwAXn3/FVzXisudI5TOZnHzz5Gr979SWnMOH5iA+K 4+/kDhlouJUqWR5ki4zojzupAVmtWnHtDxkCN59pVSX3fD/ab6plk31HXR8/R7SuLyX1iL TvxmnZsEStlLhS0XNsbCfHDaSbq1yZg= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-14-MM0jDMqZNVSJUlu95RohfA-1; Tue, 30 May 2023 20:13:05 -0400 X-MC-Unique: MM0jDMqZNVSJUlu95RohfA-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.rdu2.redhat.com [10.11.54.4]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id DA084101A52C; Wed, 31 May 2023 00:13:04 +0000 (UTC) Received: from localhost (ovpn-12-54.pek2.redhat.com [10.72.12.54]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 0F6F3202696C; Wed, 31 May 2023 00:13:03 +0000 (UTC) Date: Wed, 31 May 2023 08:13:00 +0800 From: Baoquan He To: Zhen Lei Cc: Eric Biederman , kexec@lists.infradead.org, linux-kernel@vger.kernel.org, Michael Holzheu , Andrew Morton Subject: Re: [PATCH 1/6] kexec: fix a memory leak in crash_shrink_memory() Message-ID: References: <20230527123439.772-1-thunder.leizhen@huawei.com> <20230527123439.772-2-thunder.leizhen@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230527123439.772-2-thunder.leizhen@huawei.com> X-Scanned-By: MIMEDefang 3.1 on 10.11.54.4 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 05/27/23 at 08:34pm, Zhen Lei wrote: > If the value of parameter 'new_size' is in the semi-open and semi-closed > interval (crashk_res.end - KEXEC_CRASH_MEM_ALIGN + 1, crashk_res.end], the > calculation result of ram_res is: > ram_res->start = crashk_res.end + 1 > ram_res->end = crashk_res.end If the new_size is smaller than KEXEC_CRASH_MEM_ALIGN, does it make any sense except of testing purpose? Do we need to fail this kind of shrinking, or just shrink all the left crash memory? > The operation of function insert_resource() fails, and ram_res is not > added to iomem_resource. As a result, the memory of the control block > ram_res is leaked. > > In fact, on all architectures, the start address and size of crashk_res > are already aligned by KEXEC_CRASH_MEM_ALIGN. Therefore, we do not need to > round up crashk_res.start again. Instead, we should round up 'new_size' > in advance. > > Fixes: 6480e5a09237 ("kdump: add missing RAM resource in crash_shrink_memory()") > Fixes: 06a7f711246b ("kexec: premit reduction of the reserved memory size") > Signed-off-by: Zhen Lei > --- > kernel/kexec_core.c | 5 ++--- > 1 file changed, 2 insertions(+), 3 deletions(-) > > diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c > index 3d578c6fefee385..22acee18195a591 100644 > --- a/kernel/kexec_core.c > +++ b/kernel/kexec_core.c > @@ -1122,6 +1122,7 @@ int crash_shrink_memory(unsigned long new_size) > start = crashk_res.start; > end = crashk_res.end; > old_size = (end == 0) ? 0 : end - start + 1; > + new_size = roundup(new_size, KEXEC_CRASH_MEM_ALIGN); > if (new_size >= old_size) { > ret = (new_size == old_size) ? 0 : -EINVAL; > goto unlock; > @@ -1133,9 +1134,7 @@ int crash_shrink_memory(unsigned long new_size) > goto unlock; > } > > - start = roundup(start, KEXEC_CRASH_MEM_ALIGN); > - end = roundup(start + new_size, KEXEC_CRASH_MEM_ALIGN); > - > + end = start + new_size; > crash_free_reserved_phys_range(end, crashk_res.end); > > if ((start == end) && (crashk_res.parent != NULL)) > -- > 2.25.1 >