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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 26153C433FE for ; Wed, 15 Dec 2021 15:05:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243647AbhLOPFj (ORCPT ); Wed, 15 Dec 2021 10:05:39 -0500 Received: from ams.source.kernel.org ([145.40.68.75]:42286 "EHLO ams.source.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230271AbhLOPFj (ORCPT ); Wed, 15 Dec 2021 10:05:39 -0500 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 1B87FB81F96; Wed, 15 Dec 2021 15:05:38 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id DB1ECC34606; Wed, 15 Dec 2021 15:05:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1639580736; bh=s2oMpXjPJ0435+BpTqmrBiOo4ltgVkbXybfcxoMKRSY=; h=References:In-Reply-To:From:Date:Subject:To:Cc:From; b=ZGu65odMsR5SgOhpUSzVUNzZzc3fLMAd3NHaFUsEU9txc0FNslr8Cq1E7+gztPwOJ g87x9Uw6D7K7Vvm7gk7BsqHRNhYtgwQLJ820k0DMwzJzGjUo9/foLoKIpZc6zGvhb3 Iw8yo5yBFXGj+3WRK/Z6ImVG1TdA84W2HUkaw6AYCzLa0ut+Pt9+/a2kpdefXKMDHV nyPxVaBv4Ik/TQuLIy6LiZt3SoLHGRlNFnSilrM04Ni4TPE8nTul78mBv5Ssw89XPA SLfRTZ0xN33okkgjPhsLDt7J6avLJZzvj6n+KwQYRQr4XHLYxX0+KywZhORfaCPJWa st3qOl957yZgg== Received: by mail-ed1-f44.google.com with SMTP id z9so20892019edb.5; Wed, 15 Dec 2021 07:05:36 -0800 (PST) X-Gm-Message-State: AOAM530Zb0t2fBnp5GiwxCTRcv3g9fvqaxXiWQvicHdZiEdiRCdKd1Lo 4WkA9vYMvTFa/mLQzoRul51VbCgqCMCB8aK6iA== X-Google-Smtp-Source: ABdhPJzVX+wFzD/i3rjZ6Jl105acBDc81S5ieOfWLq7tu+QfSx1YE9ES0OvoDhnOxzMrQYyjZv1UtcE9jz41ekPlvRo= X-Received: by 2002:a05:6402:35ce:: with SMTP id z14mr15000800edc.197.1639580731708; Wed, 15 Dec 2021 07:05:31 -0800 (PST) MIME-Version: 1.0 References: <20211214040157.27443-3-kernelfans@gmail.com> <20211215021348.8766-1-kernelfans@gmail.com> <7fa6bfd1-357d-10ad-0375-a6efdc7b89e4@huawei.com> In-Reply-To: From: Rob Herring Date: Wed, 15 Dec 2021 09:05:19 -0600 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCHv3] efi: apply memblock cap after memblock_add() To: "Leizhen (ThunderTown)" Cc: Pingfan Liu , devicetree@vger.kernel.org, linux-efi , Catalin Marinas , Will Deacon , Andrew Morton , Mike Rapoport , Geert Uytterhoeven , Frank Rowand , Ard Biesheuvel , Nick Terrell , linux-arm-kernel Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org On Wed, Dec 15, 2021 at 12:53 AM Leizhen (ThunderTown) wrote: > > > > On 2021/12/15 13:29, Pingfan Liu wrote: > > On Wed, Dec 15, 2021 at 11:58:03AM +0800, Leizhen (ThunderTown) wrote: > >> > >> > >> On 2021/12/15 10:13, Pingfan Liu wrote: > >>> On arm64, during kdump kernel saves vmcore, it runs into the followin= g bug: > >>> ... > >>> [ 15.148919] usercopy: Kernel memory exposure attempt detected from= SLUB object 'kmem_cache_node' (offset 0, size 4096)! > >>> [ 15.159707] ------------[ cut here ]------------ > >>> [ 15.164311] kernel BUG at mm/usercopy.c:99! > >>> [ 15.168482] Internal error: Oops - BUG: 0 [#1] SMP > >>> [ 15.173261] Modules linked in: xfs libcrc32c crct10dif_ce ghash_ce= sha2_ce sha256_arm64 sha1_ce sbsa_gwdt ast i2c_algo_bit drm_vram_helper dr= m_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops cec drm_ttm_help= er ttm drm nvme nvme_core xgene_hwmon i2c_designware_platform i2c_designwar= e_core dm_mirror dm_region_hash dm_log dm_mod overlay squashfs zstd_decompr= ess loop > >>> [ 15.206186] CPU: 0 PID: 542 Comm: cp Not tainted 5.16.0-rc4 #1 > >>> [ 15.212006] Hardware name: GIGABYTE R272-P30-JG/MP32-AR0-JG, BIOS = F12 (SCP: 1.5.20210426) 05/13/2021 > >>> [ 15.221125] pstate: 60400009 (nZCv daif +PAN -UAO -TCO -DIT -SSBS = BTYPE=3D--) > >>> [ 15.228073] pc : usercopy_abort+0x9c/0xa0 > >>> [ 15.232074] lr : usercopy_abort+0x9c/0xa0 > >>> [ 15.236070] sp : ffff8000121abba0 > >>> [ 15.239371] x29: ffff8000121abbb0 x28: 0000000000003000 x27: 00000= 00000000000 > >>> [ 15.246494] x26: 0000000080000400 x25: 0000ffff885c7000 x24: 00000= 00000000000 > >>> [ 15.253617] x23: 000007ff80400000 x22: ffff07ff80401000 x21: 00000= 00000000001 > >>> [ 15.260739] x20: 0000000000001000 x19: ffff07ff80400000 x18: fffff= fffffffffff > >>> [ 15.267861] x17: 656a626f2042554c x16: 53206d6f72662064 x15: 65746= 36574656420 > >>> [ 15.274983] x14: 74706d6574746120 x13: 2129363930342065 x12: 7a697= 3202c302074 > >>> [ 15.282105] x11: ffffc8b041d1b148 x10: 00000000ffff8000 x9 : ffffc= 8b04012812c > >>> [ 15.289228] x8 : 00000000ffff7fff x7 : ffffc8b041d1b148 x6 : 00000= 00000000000 > >>> [ 15.296349] x5 : 0000000000000000 x4 : 0000000000007fff x3 : 00000= 00000000000 > >>> [ 15.303471] x2 : 0000000000000000 x1 : ffff07ff8c064800 x0 : 00000= 0000000006b > >>> [ 15.310593] Call trace: > >>> [ 15.313027] usercopy_abort+0x9c/0xa0 > >>> [ 15.316677] __check_heap_object+0xd4/0xf0 > >>> [ 15.320762] __check_object_size.part.0+0x160/0x1e0 > >>> [ 15.325628] __check_object_size+0x2c/0x40 > >>> [ 15.329711] copy_oldmem_page+0x7c/0x140 > >>> [ 15.333623] read_from_oldmem.part.0+0xfc/0x1c0 > >>> [ 15.338142] __read_vmcore.constprop.0+0x23c/0x350 > >>> [ 15.342920] read_vmcore+0x28/0x34 > >>> [ 15.346309] proc_reg_read+0xb4/0xf0 > >>> [ 15.349871] vfs_read+0xb8/0x1f0 > >>> [ 15.353088] ksys_read+0x74/0x100 > >>> [ 15.356390] __arm64_sys_read+0x28/0x34 > >>> ... > >>> > >>> This bug introduced by commit b261dba2fdb2 ("arm64: kdump: Remove cus= tom > >>> linux,usable-memory-range handling"), which moves > >>> memblock_cap_memory_range() to fdt, but it breaches the rules that > >>> memblock_cap_memory_range() should come after memblock_add() etc as s= aid > >>> in commit e888fa7bb882 ("memblock: Check memory add/cap ordering"). > >> > >> void __init early_init_dt_scan_nodes(void) > >> { > >> //(1) -->early_init_dt_check_for_usable_mem_range, fill cap_mem_a= ddr > >> rc =3D of_scan_flat_dt(early_init_dt_scan_chosen, boot_command= _line); > >> > >> //(2) --> early_init_dt_add_memory_arch --> memblock_add() > >> of_scan_flat_dt(early_init_dt_scan_memory, NULL); > >> > >> //(3) > >> memblock_cap_memory_range(cap_mem_addr, cap_mem_size); > >> } > >> > >> I didn't get it. The above step (1),(2),(3) comply with > >> commit e888fa7bb882 ("memblock: Check memory add/cap ordering") > >> > > Well, at this scope, it does. But from a larger scope, let's say on > > arm64, > > setup_arch > > ... > > setup_machine_fdt(); //which holds your case > > ... > > efi_init(); //which call memblock_add, and breach the ordering. > > > >> Did you see the warning? > >> pr_warn("%s: No memory registered yet\n", __func__); > >> > > Yes, I did see this message, which brings me to commit e888fa7bb882 > > ("memblock: Check memory add/cap ordering") > > > > I am also curious why this bug does not be discovered. Is CONFIG_EFI > > on at your case? > > Yes, Both X86 and ARM64, CONFIG_EFI=3Dy. I used the defconfig. Are you booting using EFI though? efi_init() removes all memblocks that may have been setup from the DT and adds memblocks using the EFI memory map information. Rob