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 D834FE776F2 for ; Tue, 3 Oct 2023 03:08:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230030AbjJCDIo (ORCPT ); Mon, 2 Oct 2023 23:08:44 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58680 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229866AbjJCDIm (ORCPT ); Mon, 2 Oct 2023 23:08:42 -0400 Received: from mx0b-0031df01.pphosted.com (mx0b-0031df01.pphosted.com [205.220.180.131]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1BA84BD; Mon, 2 Oct 2023 20:08:39 -0700 (PDT) Received: from pps.filterd (m0279870.ppops.net [127.0.0.1]) by mx0a-0031df01.pphosted.com (8.17.1.19/8.17.1.19) with ESMTP id 3932iduH019401; Tue, 3 Oct 2023 03:08:26 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=quicinc.com; h=date : from : to : cc : subject : message-id : references : mime-version : content-type : content-transfer-encoding : in-reply-to; s=qcppdkim1; bh=+sWsm5qtm4vswHnIfyAJk3RpqFmAXoJi+tBhHkSooFE=; b=GdmZGGQhvhcXN7eBvCUUs0N0hmYy1NvPP2R3e7P5Wpjjgmx94GCtzPVzXkY8UBUCdYTv WIzeSwBzp27rN3JV8tcWI5PbRxLJg8F4x9NijBLTYzaPBUOFaUQ6fLX4v7zAYYBpVhjj OyJEAiLnwY11fY2lTaRoZgjY8GynpgfWlfRPG+lk5RbgntJ1xAyQdFu1SXkykl9WfSDD JsgLtnajXLnPX9k+71pVr3qTWRPL3nx50yLNE5QQk2bn26riwNiPx9Ob9xWo+ketjfrP voUDF0H1TV0SXovsstKYW+Bv/uGR5bdNE5DoLh71b9Lzrm/eErw0myazJ2tmhnAAapYC Vg== Received: from nalasppmta02.qualcomm.com (Global_NAT1.qualcomm.com [129.46.96.20]) by mx0a-0031df01.pphosted.com (PPS) with ESMTPS id 3tg9hdr3sj-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 03 Oct 2023 03:08:26 +0000 Received: from nalasex01a.na.qualcomm.com (nalasex01a.na.qualcomm.com [10.47.209.196]) by NALASPPMTA02.qualcomm.com (8.17.1.5/8.17.1.5) with ESMTPS id 39338PcM016133 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 3 Oct 2023 03:08:25 GMT Received: from hu-pkondeti-hyd.qualcomm.com (10.80.80.8) by nalasex01a.na.qualcomm.com (10.47.209.196) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1118.36; Mon, 2 Oct 2023 20:08:20 -0700 Date: Tue, 3 Oct 2023 08:38:17 +0530 From: Pavan Kondeti To: Brian Geffon CC: Pavankumar Kondeti , "Rafael J. Wysocki" , Pavel Machek , Len Brown , , "Rafael J. Wysocki" , , Subject: Re: [PATCH] PM: hibernate: Fix a bug in copying the zero bitmap to safe pages Message-ID: <990198cf-59bb-484d-9383-dd7d133c8105@quicinc.com> References: <20230929-hib_zero_bitmap_fix-v1-1-6cfdcb785250@quicinc.com> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: X-Originating-IP: [10.80.80.8] X-ClientProxiedBy: nasanex01b.na.qualcomm.com (10.46.141.250) To nalasex01a.na.qualcomm.com (10.47.209.196) X-QCInternal: smtphost X-Proofpoint-Virus-Version: vendor=nai engine=6200 definitions=5800 signatures=585085 X-Proofpoint-ORIG-GUID: xWW8-eUTp8WOrdZacg7tD8qMByB0i1l5 X-Proofpoint-GUID: xWW8-eUTp8WOrdZacg7tD8qMByB0i1l5 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.267,Aquarius:18.0.980,Hydra:6.0.619,FMLib:17.11.176.26 definitions=2023-10-02_16,2023-10-02_01,2023-05-22_02 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 adultscore=0 lowpriorityscore=0 phishscore=0 clxscore=1015 mlxscore=0 suspectscore=0 impostorscore=0 mlxlogscore=574 malwarescore=0 spamscore=0 priorityscore=1501 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2309180000 definitions=main-2310030024 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Sep 30, 2023 at 07:37:13AM -0400, Brian Geffon wrote: > On Fri, Sep 29, 2023 at 1:31 PM Pavankumar Kondeti > wrote: > > > Hi Pavankumar, > > > The following crash is observed 100% of the time during resume from > > the hibernation on a x86 QEMU system. > > > > [ 12.931887] ? __die_body+0x1a/0x60 > > [ 12.932324] ? page_fault_oops+0x156/0x420 > > [ 12.932824] ? search_exception_tables+0x37/0x50 > > [ 12.933389] ? fixup_exception+0x21/0x300 > > [ 12.933889] ? exc_page_fault+0x69/0x150 > > [ 12.934371] ? asm_exc_page_fault+0x26/0x30 > > [ 12.934869] ? get_buffer.constprop.0+0xac/0x100 > > [ 12.935428] snapshot_write_next+0x7c/0x9f0 > > [ 12.935929] ? submit_bio_noacct_nocheck+0x2c2/0x370 > > [ 12.936530] ? submit_bio_noacct+0x44/0x2c0 > > [ 12.937035] ? hib_submit_io+0xa5/0x110 > > [ 12.937501] load_image+0x83/0x1a0 > > [ 12.937919] swsusp_read+0x17f/0x1d0 > > [ 12.938355] ? create_basic_memory_bitmaps+0x1b7/0x240 > > [ 12.938967] load_image_and_restore+0x45/0xc0 > > [ 12.939494] software_resume+0x13c/0x180 > > [ 12.939994] resume_store+0xa3/0x1d0 > > > > The commit being fixed introduced a bug in copying the zero bitmap > > to safe pages. A temporary bitmap is allocated in prepare_image() > > to make a copy of zero bitmap after the unsafe pages are marked. > > Freeing this temporary bitmap later results in an inconsistent state > > of unsafe pages. Since free bit is left as is for this temporary bitmap > > after free, these pages are treated as unsafe pages when they are > > allocated again. This results in incorrect calculation of the number > > of pages pre-allocated for the image. > > > > nr_pages = (nr_zero_pages + nr_copy_pages) - nr_highmem - allocated_unsafe_pages; > > > > The allocate_unsafe_pages is estimated to be higher than the actual > > which results in running short of pages in safe_pages_list. Hence the > > crash is observed in get_buffer() due to NULL pointer access of > > safe_pages_list. > > Rafael pulled https://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm.git/commit/?h=linux-next&id=f0c7183008b41e92fa676406d87f18773724b48b > which addresses the null pointer dereference which regardless > shouldn't be touching the list directly and should be using > __get_safe_page(). Thanks for pointing me to this. I have verified hibernation by pulling this commit to v6.6-rc3 and it works as expected. This commit is currently queued for v6.7, can it be included in next -rc or we have to apply the patch I have sent to make sure that hibernation works on v6.6 when it gets released. > > > > > Fixes: 005e8dddd497 ("PM: hibernate: don't store zero pages in the image file") > > Signed-off-by: Pavankumar Kondeti Thanks, Pavan