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=-18.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,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 1CC87C4332D for ; Mon, 22 Feb 2021 13:28:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E633664E27 for ; Mon, 22 Feb 2021 13:28:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231998AbhBVN2E (ORCPT ); Mon, 22 Feb 2021 08:28:04 -0500 Received: from mail.kernel.org ([198.145.29.99]:53432 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231374AbhBVMmM (ORCPT ); Mon, 22 Feb 2021 07:42:12 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 6A06D64F26; Mon, 22 Feb 2021 12:39:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1613997572; bh=UJpuyH9VDtyGKbKla09NNeb4DvUagLcl7ZynoO+Dckg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=wi1H/s2YHoDXgpvX+rfqKOVCBQC/2aQt6E04wnz44OTolgIZikLD0z0u4o3CCmt+p J4m/CwaQA6dfPhVRFm8BO2QTs2YpjdDhkiPHIXmD83/M36THlhyHsxvQ0sVU+x675q ngIK5qjNxt9vRlFpVq6udCghbSYGlxOn/7vDZfq4= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Roman Gushchin , Mike Rapoport , Joonsoo Kim , Michal Hocko , Rik van Riel , Wonhyuk Yang , Thiago Jung Bauermann , Andrew Morton , Linus Torvalds , Sasha Levin Subject: [PATCH 4.4 14/35] memblock: do not start bottom-up allocations with kernel_end Date: Mon, 22 Feb 2021 13:36:10 +0100 Message-Id: <20210222121019.452837496@linuxfoundation.org> X-Mailer: git-send-email 2.30.1 In-Reply-To: <20210222121013.581198717@linuxfoundation.org> References: <20210222121013.581198717@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Roman Gushchin [ Upstream commit 2dcb3964544177c51853a210b6ad400de78ef17d ] With kaslr the kernel image is placed at a random place, so starting the bottom-up allocation with the kernel_end can result in an allocation failure and a warning like this one: hugetlb_cma: reserve 2048 MiB, up to 2048 MiB per node ------------[ cut here ]------------ memblock: bottom-up allocation failed, memory hotremove may be affected WARNING: CPU: 0 PID: 0 at mm/memblock.c:332 memblock_find_in_range_node+0x178/0x25a Modules linked in: CPU: 0 PID: 0 Comm: swapper Not tainted 5.10.0+ #1169 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-1.fc33 04/01/2014 RIP: 0010:memblock_find_in_range_node+0x178/0x25a Code: e9 6d ff ff ff 48 85 c0 0f 85 da 00 00 00 80 3d 9b 35 df 00 00 75 15 48 c7 c7 c0 75 59 88 c6 05 8b 35 df 00 01 e8 25 8a fa ff <0f> 0b 48 c7 44 24 20 ff ff ff ff 44 89 e6 44 89 ea 48 c7 c1 70 5c RSP: 0000:ffffffff88803d18 EFLAGS: 00010086 ORIG_RAX: 0000000000000000 RAX: 0000000000000000 RBX: 0000000240000000 RCX: 00000000ffffdfff RDX: 00000000ffffdfff RSI: 00000000ffffffea RDI: 0000000000000046 RBP: 0000000100000000 R08: ffffffff88922788 R09: 0000000000009ffb R10: 00000000ffffe000 R11: 3fffffffffffffff R12: 0000000000000000 R13: 0000000000000000 R14: 0000000080000000 R15: 00000001fb42c000 FS: 0000000000000000(0000) GS:ffffffff88f71000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffa080fb401000 CR3: 00000001fa80a000 CR4: 00000000000406b0 Call Trace: memblock_alloc_range_nid+0x8d/0x11e cma_declare_contiguous_nid+0x2c4/0x38c hugetlb_cma_reserve+0xdc/0x128 flush_tlb_one_kernel+0xc/0x20 native_set_fixmap+0x82/0xd0 flat_get_apic_id+0x5/0x10 register_lapic_address+0x8e/0x97 setup_arch+0x8a5/0xc3f start_kernel+0x66/0x547 load_ucode_bsp+0x4c/0xcd secondary_startup_64_no_verify+0xb0/0xbb random: get_random_bytes called from __warn+0xab/0x110 with crng_init=0 ---[ end trace f151227d0b39be70 ]--- At the same time, the kernel image is protected with memblock_reserve(), so we can just start searching at PAGE_SIZE. In this case the bottom-up allocation has the same chances to success as a top-down allocation, so there is no reason to fallback in the case of a failure. All together it simplifies the logic. Link: https://lkml.kernel.org/r/20201217201214.3414100-2-guro@fb.com Fixes: 8fabc623238e ("powerpc: Ensure that swiotlb buffer is allocated from low memory") Signed-off-by: Roman Gushchin Reviewed-by: Mike Rapoport Cc: Joonsoo Kim Cc: Michal Hocko Cc: Rik van Riel Cc: Wonhyuk Yang Cc: Thiago Jung Bauermann Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin --- mm/memblock.c | 49 ++++++------------------------------------------- 1 file changed, 6 insertions(+), 43 deletions(-) diff --git a/mm/memblock.c b/mm/memblock.c index f8fab45bfdb75..ff51a37eb86be 100644 --- a/mm/memblock.c +++ b/mm/memblock.c @@ -189,14 +189,6 @@ __memblock_find_range_top_down(phys_addr_t start, phys_addr_t end, * * Find @size free area aligned to @align in the specified range and node. * - * When allocation direction is bottom-up, the @start should be greater - * than the end of the kernel image. Otherwise, it will be trimmed. The - * reason is that we want the bottom-up allocation just near the kernel - * image so it is highly likely that the allocated memory and the kernel - * will reside in the same node. - * - * If bottom-up allocation failed, will try to allocate memory top-down. - * * RETURNS: * Found address on success, 0 on failure. */ @@ -204,8 +196,6 @@ phys_addr_t __init_memblock memblock_find_in_range_node(phys_addr_t size, phys_addr_t align, phys_addr_t start, phys_addr_t end, int nid, ulong flags) { - phys_addr_t kernel_end, ret; - /* pump up @end */ if (end == MEMBLOCK_ALLOC_ACCESSIBLE) end = memblock.current_limit; @@ -213,40 +203,13 @@ phys_addr_t __init_memblock memblock_find_in_range_node(phys_addr_t size, /* avoid allocating the first page */ start = max_t(phys_addr_t, start, PAGE_SIZE); end = max(start, end); - kernel_end = __pa_symbol(_end); - - /* - * try bottom-up allocation only when bottom-up mode - * is set and @end is above the kernel image. - */ - if (memblock_bottom_up() && end > kernel_end) { - phys_addr_t bottom_up_start; - - /* make sure we will allocate above the kernel */ - bottom_up_start = max(start, kernel_end); - /* ok, try bottom-up allocation first */ - ret = __memblock_find_range_bottom_up(bottom_up_start, end, - size, align, nid, flags); - if (ret) - return ret; - - /* - * we always limit bottom-up allocation above the kernel, - * but top-down allocation doesn't have the limit, so - * retrying top-down allocation may succeed when bottom-up - * allocation failed. - * - * bottom-up allocation is expected to be fail very rarely, - * so we use WARN_ONCE() here to see the stack trace if - * fail happens. - */ - WARN_ONCE(1, "memblock: bottom-up allocation failed, " - "memory hotunplug may be affected\n"); - } - - return __memblock_find_range_top_down(start, end, size, align, nid, - flags); + if (memblock_bottom_up()) + return __memblock_find_range_bottom_up(start, end, size, align, + nid, flags); + else + return __memblock_find_range_top_down(start, end, size, align, + nid, flags); } /** -- 2.27.0