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=-7.0 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 autolearn=no 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 85204C433E3 for ; Wed, 12 Aug 2020 01:32:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5DC87207DA for ; Wed, 12 Aug 2020 01:32:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1597195928; bh=gFsJfQTsHVBklo2noIvAaivjZuyl2sPhMLKPktO/beU=; h=Date:From:To:Subject:In-Reply-To:Reply-To:List-ID:From; b=Rzs8uOt2erLyo+/9qvsH5EMVcvgkqvDsfXw8pRp1+YeH1rLfx8CuYJNpKWrlniYnW pzekxge1jEtnUCHf68kkAAgY7kVWrVclmz0cvxJxY4VHKDNmbzPnJfDhBXu54+IicG W/DXrGRQfq7NQ8l5BIkU5fFv1gC88GYO0Uk5AorA= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726707AbgHLBcF (ORCPT ); Tue, 11 Aug 2020 21:32:05 -0400 Received: from mail.kernel.org ([198.145.29.99]:60144 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726531AbgHLBcF (ORCPT ); Tue, 11 Aug 2020 21:32:05 -0400 Received: from localhost.localdomain (c-73-231-172-41.hsd1.ca.comcast.net [73.231.172.41]) (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 EBD55206B2; Wed, 12 Aug 2020 01:32:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1597195924; bh=gFsJfQTsHVBklo2noIvAaivjZuyl2sPhMLKPktO/beU=; h=Date:From:To:Subject:In-Reply-To:From; b=LG0fqlfHHccdBcury3qaI4W3jNZ5qXea8dJ5ZB1KdrdePvP9eMnRAvdLeDva6vi6s 4Gv9JINo4vwQqAHFfpG40X3oASTn93VZ5B3wXqQ9MA3UiV3SCO64CLAdOmwywsp79A Xu2fIZH75/strLlTyTt1SFjnCRXVKusWdBHqzCH8= Date: Tue, 11 Aug 2020 18:32:03 -0700 From: Andrew Morton To: akpm@linux-foundation.org, guro@fb.com, iamjoonsoo.kim@lge.com, kyungmin.park@samsung.com, linux-mm@kvack.org, m.szyprowski@samsung.com, mike.kravetz@oracle.com, mina86@mina86.com, mm-commits@vger.kernel.org, song.bao.hua@hisilicon.com, stable@vger.kernel.org, torvalds@linux-foundation.org Subject: [patch 034/165] cma: don't quit at first error when activating reserved areas Message-ID: <20200812013203.Dh6_amkhG%akpm@linux-foundation.org> In-Reply-To: <20200811182949.e12ae9a472e3b5e27e16ad6c@linux-foundation.org> User-Agent: s-nail v14.8.16 Sender: mm-commits-owner@vger.kernel.org Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org From: Mike Kravetz Subject: cma: don't quit at first error when activating reserved areas 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 Link: http://lkml.kernel.org/r/20200730163123.6451-1-mike.kravetz@oracle.com Fixes: c64be2bb1c6e ("drivers: add Contiguous Memory Allocator") Signed-off-by: Mike Kravetz Reviewed-by: Roman Gushchin Acked-by: Barry Song Cc: Marek Szyprowski Cc: Michal Nazarewicz Cc: Kyungmin Park Cc: Joonsoo Kim Cc: Signed-off-by: Andrew Morton --- mm/cma.c | 23 +++++++++-------------- 1 file changed, 9 insertions(+), 14 deletions(-) --- a/mm/cma.c~cma-dont-quit-at-first-error-when-activating-reserved-areas +++ a/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; } _