From patchwork Tue Sep 1 15:09:23 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 310311 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=-13.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, 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 2E9ECC433E2 for ; Tue, 1 Sep 2020 16:35:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0B27320767 for ; Tue, 1 Sep 2020 16:35:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1598978140; bh=pv5+ct0WOPpI6PgAzSEL0FqEv8tW97yD1vGjkjgCw98=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=JhPAWu3dU796EV4aavCeQIchmX+KGvmL1jqfVjIaIF6cxyqBoRMdYgEi5J/dvgbcw BirHcxne0j4ntCERFCQkDoI1I+0bpjgc9OG87G7L+Y4M3TFlkKbV5jClLQZLcMSAOc rmC7s8iLp9igcp7jcsixkx21x3AtLm/qknqPHws4= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730592AbgIAPaP (ORCPT ); Tue, 1 Sep 2020 11:30:15 -0400 Received: from mail.kernel.org ([198.145.29.99]:59952 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730299AbgIAPaA (ORCPT ); Tue, 1 Sep 2020 11:30:00 -0400 Received: from localhost (83-86-74-64.cable.dynamic.v4.ziggo.nl [83.86.74.64]) (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 20FB820684; Tue, 1 Sep 2020 15:29:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1598974199; bh=pv5+ct0WOPpI6PgAzSEL0FqEv8tW97yD1vGjkjgCw98=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=aU/84PAmsViEEENWrGfd7vRA6mQoPQJxr4xegAltPLbDNs4pOIJJJnuBwn5beD+vq n9Lxu7Eq/TwnnBD8KK30gNIzESPQGsK0K4Pj5W22GCykKZQ/lgp6ckqqNc1Gzg8RLx +Peh7PgQ5M63N6zw5op8l8SinjcC2G5WrQh57AHU= 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 , Sasha Levin Subject: [PATCH 5.4 083/214] cma: dont quit at first error when activating reserved areas Date: Tue, 1 Sep 2020 17:09:23 +0200 Message-Id: <20200901150956.973985422@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200901150952.963606936@linuxfoundation.org> References: <20200901150952.963606936@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Mike Kravetz [ Upstream commit 3a5139f1c5bb76d69756fb8f13fffa173e261153 ] 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: Sasha Levin --- mm/cma.c | 23 +++++++++-------------- 1 file changed, 9 insertions(+), 14 deletions(-) diff --git a/mm/cma.c b/mm/cma.c index be55d1988c675..7de520c0a1db6 100644 --- a/mm/cma.c +++ b/mm/cma.c @@ -93,17 +93,15 @@ static void cma_clear_bitmap(struct cma *cma, unsigned long pfn, 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(struct cma *cma) 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; }