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=-9.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 99C98C433E1 for ; Thu, 20 Aug 2020 13:50:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6CD9E2076E for ; Thu, 20 Aug 2020 13:50:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1597931401; bh=3rhEvQdtaZVkjicRvpomqlnahjTQxYkIgWBGzz3QM9k=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=q6ro9OwX9krLUtWjv72/WKGxCCHm+9afMUm5A3/3DBCwycBizrmNISMHUmWVYB1aF L1dD5KtWk8RxmOq7GGEXKdS5lvMFNRU4i1f3VFGnujYV622QDg9z9HDv+hhzCH1/cg Xe+A8rqK2GCate+M8g3a7m+agTS2iGej6QoXZUdc= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728813AbgHTNts (ORCPT ); Thu, 20 Aug 2020 09:49:48 -0400 Received: from mail.kernel.org ([198.145.29.99]:35748 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726976AbgHTJ12 (ORCPT ); Thu, 20 Aug 2020 05:27:28 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id A075222CB2; Thu, 20 Aug 2020 09:27:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1597915647; bh=3rhEvQdtaZVkjicRvpomqlnahjTQxYkIgWBGzz3QM9k=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=0PSCRNIRdjkkhF9LId25pAzCo+NPBU/8MFCyCcxCplJWBccgP8Sm26ylqKt8efigL I72z5JMwfsPFhz4inmZte4P7g4wILyOnFRsiYSeMHiCS0T565jm7h33GuY3WhQhWqc LMYGD9+6uZ1J3lbKCgX1B9knDjEm00OyDIG45BlQ= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Mike Kravetz , Andrew Morton , Roman Gushchin , Barry Song , Marek Szyprowski , Michal Nazarewicz , Kyungmin Park , Joonsoo Kim , Linus Torvalds Subject: [PATCH 5.8 086/232] cma: dont quit at first error when activating reserved areas Date: Thu, 20 Aug 2020 11:18:57 +0200 Message-Id: <20200820091616.985592986@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200820091612.692383444@linuxfoundation.org> References: <20200820091612.692383444@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Mike Kravetz commit 3a5139f1c5bb76d69756fb8f13fffa173e261153 upstream. The routine cma_init_reserved_areas is designed to activate all reserved cma areas. It quits when it first encounters an error. This can leave some areas in a state where they are reserved but not activated. There is no feedback to code which performed the reservation. Attempting to allocate memory from areas in such a state will result in a BUG. Modify cma_init_reserved_areas to always attempt to activate all areas. The called routine, cma_activate_area is responsible for leaving the area in a valid state. No one is making active use of returned error codes, so change the routine to void. How to reproduce: This example uses kernelcore, hugetlb and cma as an easy way to reproduce. However, this is a more general cma issue. Two node x86 VM 16GB total, 8GB per node Kernel command line parameters, kernelcore=4G hugetlb_cma=8G Related boot time messages, hugetlb_cma: reserve 8192 MiB, up to 4096 MiB per node cma: Reserved 4096 MiB at 0x0000000100000000 hugetlb_cma: reserved 4096 MiB on node 0 cma: Reserved 4096 MiB at 0x0000000300000000 hugetlb_cma: reserved 4096 MiB on node 1 cma: CMA area hugetlb could not be activated # echo 8 > /sys/kernel/mm/hugepages/hugepages-1048576kB/nr_hugepages BUG: kernel NULL pointer dereference, address: 0000000000000000 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 0 P4D 0 Oops: 0000 [#1] SMP PTI ... Call Trace: bitmap_find_next_zero_area_off+0x51/0x90 cma_alloc+0x1a5/0x310 alloc_fresh_huge_page+0x78/0x1a0 alloc_pool_huge_page+0x6f/0xf0 set_max_huge_pages+0x10c/0x250 nr_hugepages_store_common+0x92/0x120 ? __kmalloc+0x171/0x270 kernfs_fop_write+0xc1/0x1a0 vfs_write+0xc7/0x1f0 ksys_write+0x5f/0xe0 do_syscall_64+0x4d/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Fixes: c64be2bb1c6e ("drivers: add Contiguous Memory Allocator") Signed-off-by: Mike Kravetz Signed-off-by: Andrew Morton Reviewed-by: Roman Gushchin Acked-by: Barry Song Cc: Marek Szyprowski Cc: Michal Nazarewicz Cc: Kyungmin Park Cc: Joonsoo Kim Cc: Link: http://lkml.kernel.org/r/20200730163123.6451-1-mike.kravetz@oracle.com Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- mm/cma.c | 23 +++++++++-------------- 1 file changed, 9 insertions(+), 14 deletions(-) --- a/mm/cma.c +++ b/mm/cma.c @@ -93,17 +93,15 @@ static void cma_clear_bitmap(struct cma mutex_unlock(&cma->lock); } -static int __init cma_activate_area(struct cma *cma) +static void __init cma_activate_area(struct cma *cma) { unsigned long base_pfn = cma->base_pfn, pfn = base_pfn; unsigned i = cma->count >> pageblock_order; struct zone *zone; cma->bitmap = bitmap_zalloc(cma_bitmap_maxno(cma), GFP_KERNEL); - if (!cma->bitmap) { - cma->count = 0; - return -ENOMEM; - } + if (!cma->bitmap) + goto out_error; WARN_ON_ONCE(!pfn_valid(pfn)); zone = page_zone(pfn_to_page(pfn)); @@ -133,25 +131,22 @@ static int __init cma_activate_area(stru spin_lock_init(&cma->mem_head_lock); #endif - return 0; + return; not_in_zone: - pr_err("CMA area %s could not be activated\n", cma->name); bitmap_free(cma->bitmap); +out_error: cma->count = 0; - return -EINVAL; + pr_err("CMA area %s could not be activated\n", cma->name); + return; } static int __init cma_init_reserved_areas(void) { int i; - for (i = 0; i < cma_area_count; i++) { - int ret = cma_activate_area(&cma_areas[i]); - - if (ret) - return ret; - } + for (i = 0; i < cma_area_count; i++) + cma_activate_area(&cma_areas[i]); return 0; }