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=-16.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 18750C433DB for ; Sun, 28 Feb 2021 09:01:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C637764E55 for ; Sun, 28 Feb 2021 09:01:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230382AbhB1JBf (ORCPT ); Sun, 28 Feb 2021 04:01:35 -0500 Received: from mail.kernel.org ([198.145.29.99]:40122 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230075AbhB1JBd (ORCPT ); Sun, 28 Feb 2021 04:01:33 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 9121464E38; Sun, 28 Feb 2021 09:00:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1614502850; bh=8mA43d4QxG1l5TgOlrLJX5S5pb5qni0CUaJ+AOPZGK0=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=UF71Mq5Ww46r6dBcQL4HzYIaQ5z0eqD6pT/ugfzkxRKfJwgGkGn5YV6774jEEP0DE t/LGLiaVLPpDH3R8xqfaoiIEzhxBrAvVukTRF1WDLa0vjwm97AVKHP9+0dssP7iyn6 ATvPJf+p6he86e9U/IN2/hCvp0v6VDnj6V5I786zPla0cf9SvuoyJrUBUSV4DCuVbM WwlgXD89SO4N4It4pmgYNJfZB7fCrLdpINehc6xFptsp1P/NVPf2AzaVWADRjpB31n BjJqIV1lUVH1Q8IYrQ78kUizbqVWN+w54n3va2X9v03NY43vmSlRk6apjPvo9UegXK kdxTTC5q37a2g== Date: Sun, 28 Feb 2021 11:00:41 +0200 From: Mike Rapoport To: Florian Fainelli Cc: Roman Gushchin , Andrew Morton , linux-mm@kvack.org, Kamal Dasu , linux-mips@linux-mips.org, Thomas Bogendoerfer , Paul Cercueil , Serge Semin , Jiaxun Yang , iamjoonsoo.kim@lge.com, riel@surriel.com, Michal Hocko , linux-kernel@vger.kernel.org, kernel-team@fb.com Subject: Re: [PATCH v2 2/2] memblock: do not start bottom-up allocations with kernel_end Message-ID: <20210228090041.GO1447004@kernel.org> References: <20201217201214.3414100-1-guro@fb.com> <20201217201214.3414100-2-guro@fb.com> <23fc1ef9-7342-8bc2-d184-d898107c52b2@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <23fc1ef9-7342-8bc2-d184-d898107c52b2@gmail.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Florian, On Sat, Feb 27, 2021 at 08:18:47PM -0800, Florian Fainelli wrote: > > On 12/17/2020 12:12 PM, Roman Gushchin wrote: > > 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: > > > > [ 0.002920] hugetlb_cma: reserve 2048 MiB, up to 2048 MiB per node > > [ 0.002921] ------------[ cut here ]------------ > > [ 0.002922] memblock: bottom-up allocation failed, memory hotremove may be affected > > [ 0.002937] WARNING: CPU: 0 PID: 0 at mm/memblock.c:332 memblock_find_in_range_node+0x178/0x25a > > [ 0.002937] Modules linked in: > > [ 0.002939] CPU: 0 PID: 0 Comm: swapper Not tainted 5.10.0+ #1169 > > [ 0.002940] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-1.fc33 04/01/2014 > > [ 0.002942] RIP: 0010:memblock_find_in_range_node+0x178/0x25a > > [ 0.002944] 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 > > [ 0.002945] RSP: 0000:ffffffff88803d18 EFLAGS: 00010086 ORIG_RAX: 0000000000000000 > > [ 0.002947] RAX: 0000000000000000 RBX: 0000000240000000 RCX: 00000000ffffdfff > > [ 0.002948] RDX: 00000000ffffdfff RSI: 00000000ffffffea RDI: 0000000000000046 > > [ 0.002948] RBP: 0000000100000000 R08: ffffffff88922788 R09: 0000000000009ffb > > [ 0.002949] R10: 00000000ffffe000 R11: 3fffffffffffffff R12: 0000000000000000 > > [ 0.002950] R13: 0000000000000000 R14: 0000000080000000 R15: 00000001fb42c000 > > [ 0.002952] FS: 0000000000000000(0000) GS:ffffffff88f71000(0000) knlGS:0000000000000000 > > [ 0.002953] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > > [ 0.002954] CR2: ffffa080fb401000 CR3: 00000001fa80a000 CR4: 00000000000406b0 > > [ 0.002956] Call Trace: > > [ 0.002961] ? memblock_alloc_range_nid+0x8d/0x11e > > [ 0.002963] ? cma_declare_contiguous_nid+0x2c4/0x38c > > [ 0.002964] ? hugetlb_cma_reserve+0xdc/0x128 > > [ 0.002968] ? flush_tlb_one_kernel+0xc/0x20 > > [ 0.002969] ? native_set_fixmap+0x82/0xd0 > > [ 0.002971] ? flat_get_apic_id+0x5/0x10 > > [ 0.002973] ? register_lapic_address+0x8e/0x97 > > [ 0.002975] ? setup_arch+0x8a5/0xc3f > > [ 0.002978] ? start_kernel+0x66/0x547 > > [ 0.002980] ? load_ucode_bsp+0x4c/0xcd > > [ 0.002982] ? secondary_startup_64_no_verify+0xb0/0xbb > > [ 0.002986] random: get_random_bytes called from __warn+0xab/0x110 with crng_init=0 > > [ 0.002988] ---[ 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. > > > > Signed-off-by: Roman Gushchin > > Hi Roman, Thomas and other linux-mips folks, > > Kamal and myself have been unable to boot v5.11 on MIPS since this > commit, reverting it makes our MIPS platforms boot successfully. We do > not see a warning like this one in the commit message, instead what > happens appear to be a corrupted Device Tree which prevents the parsing > of the "rdb" node and leading to the interrupt controllers not being > registered, and the system eventually not booting. > > The Device Tree is built-into the kernel image and resides at > arch/mips/boot/dts/brcm/bcm97435svmb.dts. > > Do you have any idea what could be wrong with MIPS specifically here? Apparently there is a memblock allocation in one of the functions called from arch_mem_init() between plat_mem_setup() and early_init_fdt_reserve_self(). If you have serial available that early we can try to track it down with forcing memblock_debug in mm/memblock.c to 1: diff --git a/mm/memblock.c b/mm/memblock.c index afaefa8fc6ab..83034245f8d5 100644 --- a/mm/memblock.c +++ b/mm/memblock.c @@ -151,7 +151,7 @@ static __refdata struct memblock_type *memblock_memory = &memblock.memory; pr_info(fmt, ##__VA_ARGS__); \ } while (0) -static int memblock_debug __initdata_memblock; +static int memblock_debug __initdata_memblock = 1; static bool system_has_some_mirror __initdata_memblock = false; static int memblock_can_resize __initdata_memblock; static int memblock_memory_in_slab __initdata_memblock = 0; Regardless, I think that moving DT self reservation just after plat_mem_setup() is safe and it'll make things more robust. diff --git a/arch/mips/kernel/setup.c b/arch/mips/kernel/setup.c index 279be0153f8b..f476b99a7bcd 100644 --- a/arch/mips/kernel/setup.c +++ b/arch/mips/kernel/setup.c @@ -623,6 +623,8 @@ static void __init arch_mem_init(char **cmdline_p) { /* call board setup routine */ plat_mem_setup(); + early_init_fdt_reserve_self(); + early_init_fdt_scan_reserved_mem(); memblock_set_bottom_up(true); bootcmdline_init(); @@ -636,9 +638,6 @@ static void __init arch_mem_init(char **cmdline_p) check_kernel_sections_mem(); - early_init_fdt_reserve_self(); - early_init_fdt_scan_reserved_mem(); - #ifndef CONFIG_NUMA memblock_set_node(0, PHYS_ADDR_MAX, &memblock.memory, 0); #endif -- Sincerely yours, Mike.