From patchwork Fri Aug 26 22:00:17 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Marek Bykowski X-Patchwork-Id: 600421 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 14764C0502A for ; Fri, 26 Aug 2022 22:00:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241599AbiHZWA4 (ORCPT ); Fri, 26 Aug 2022 18:00:56 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46350 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243653AbiHZWAz (ORCPT ); Fri, 26 Aug 2022 18:00:55 -0400 Received: from mail-lf1-x135.google.com (mail-lf1-x135.google.com [IPv6:2a00:1450:4864:20::135]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9DE6EB2D93; Fri, 26 Aug 2022 15:00:51 -0700 (PDT) Received: by mail-lf1-x135.google.com with SMTP id q7so3644188lfu.5; Fri, 26 Aug 2022 15:00:51 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc; bh=NJbP7LG9b31evjLDHSY9Sv5bNgDsslZ78cA55vLf+o0=; b=ZakPFMHIzlQUDuerILcwgHk0id+7UlwDLYtwZjuVd+gPY9l06PH63bacOjD0pjQ18r 41X5stpzcwHIpTJT3ifb7FJXuofVDtN/9tEzvGC9hO6dni1G5Qba4HsO/tUJh0Geg1Vx eR9NMEyQXDfCh1pwioMzB/gO1wN0m8M0mmvknIFQqg9iP/1Ja35ykeM0AHH0l4hFL1/K yv/9eY+DQOId0sjTGrMtO6oaMshqhIVAbO/QkNwNbdCtN+9fySWqD8TbBcUdGwW3rchr 5J0HINVIV+Jxy5xIK4/9q3O07XqN3NO3za38NJKyxDLRKSLf+gcYT1ONATlbeKiRxPKn C1QA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-message-state:from:to:cc; bh=NJbP7LG9b31evjLDHSY9Sv5bNgDsslZ78cA55vLf+o0=; b=ik8UvvHOVnxIGa0PwAEEzLvtY3MYBDmxgb24I4eHCjwJmqguohZR4NIBioZtZ4EnYs XCmXwawvFs3RZKgbP8Uk349BHC6olvrzTSt59rlxDsPjqnsPzLfV0mIa6E2fHOiae9ah h5QbjQN5kG26ix44e/VufR+JeipQdsMxHFZR/EVQgXw59clvDJBcU0mzvz+BSqDkfprf PGfHnmJVmL391Vw2y+9FLy9yMohK7mv3eqPM8C5O7eRF/kyi3dZSdPdphNEvf1CbXN3/ P9/XlxJ39tI1F10+NFV/38xCTjfPyYDG8wHmLt4CFv6HB6ZBTEiyRCnGGPjCXn+v9jAd bCNg== X-Gm-Message-State: ACgBeo3bmCmClri6XEhFg6+5Tcj1+iXBilgJ55SsfB6FGMsSa6wCz4Lp bcrnRyjcB1qNa+JI2g2XxGs= X-Google-Smtp-Source: AA6agR5VYoZByro113IAlWjA542jSW9MLpHhvWOWO8/Z2eG8jLSunEwho9iuNGrs223OPoBx3W28iQ== X-Received: by 2002:a05:6512:3f1d:b0:492:e175:402a with SMTP id y29-20020a0565123f1d00b00492e175402amr2897682lfa.384.1661551249432; Fri, 26 Aug 2022 15:00:49 -0700 (PDT) Received: from localhost.localdomain ([89.46.86.70]) by smtp.gmail.com with ESMTPSA id d1-20020a05651221c100b0048b0ef93248sm491941lft.62.2022.08.26.15.00.48 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 26 Aug 2022 15:00:49 -0700 (PDT) From: Marek Bykowski To: Rob Herring , Frank Rowand Cc: Marek Bykowski , devicetree@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH] =?utf-8?q?of/fdt=3A_Don=27t_calculate_initrd=5Fstart_from_t?= =?utf-8?q?he_DT_if=C2=A0=27linux=2Cinitrd-end=27_is_0?= Date: Fri, 26 Aug 2022 22:00:17 +0000 Message-Id: <20220826220017.188066-1-marek.bykowski@gmail.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org If the 'linux,initrd-end' property is 0 and 'linux,initrd-start' property is other than 0, then phys_initrd_size calculated from 'linux,initrd-end' - 'linux,initrd-start' is negative, that subsequently gets converted to a high positive value as being u64. For example if 'linux,initrd-start' is 8800_0000, 'linux,initrd-end' is 0, then the phys_initrd_size calculated is ffff_ffff_7800_0000 (= 0 - 8800_0000 = -8800_0000 + ULLONG_MAX + 1). On my system, FVP ARM64, the intird memory region with the (wrong) size is added to the bootmem and then attempted to being paged in paging_init() that results in the kernel oops as shown below. Generally, it is a fault of the bootloader as the kernel is relying on it but we should not allow the bootloader's misconfiguration to lead to the kernel oops. Not only the kernel should get bullet proof against it but also finding the root cause may get lengthy on occasion as involves checking the bootloader, the chosen node it makes the changes in and the kernel. Unable to handle kernel paging request at virtual address fffffffefe43c000 Mem abort info:                                                       ESR = 0x96000007                                                                                     EC = 0x25: DABT (current EL), IL = 32 bits   SET = 0, FnV = 0                                                   EA = 0, S1PTW = 0                                                                                 Data abort info:                                                                                       ISV = 0, ISS = 0x00000007   CM = 0, WnR = 0 swapper pgtable: 4k pages, 39-bit VAs, pgdp=0000000080e3d000 [fffffffefe43c000] pgd=0000000080de9003, pud=0000000080de9003 Unable to handle kernel paging request at virtual address ffffff8000de9f90 Mem abort info:   ESR = 0x96000005   EC = 0x25: DABT (current EL), IL = 32 bits   SET = 0, FnV = 0   EA = 0, S1PTW = 0 Data abort info:   ISV = 0, ISS = 0x00000005   CM = 0, WnR = 0 swapper pgtable: 4k pages, 39-bit VAs, pgdp=0000000080e3d000 [ffffff8000de9f90] pgd=0000000000000000, pud=0000000000000000 Internal error: Oops: 96000005 [#1] PREEMPT SMP Modules linked in: CPU: 0 PID: 0 Comm: swapper Not tainted 5.4.51-yocto-standard #1 Hardware name: FVP Base (DT) pstate: 60000085 (nZCv daIf -PAN -UAO) pc : show_pte+0x12c/0x1b4 lr : show_pte+0x100/0x1b4 sp : ffffffc010ce3b30 x29: ffffffc010ce3b30 x28: ffffffc010ceed80 x27: fffffffefe43c000 x26: fffffffefe43a028 x25: 0000000080bf0000 x24: 0000000000000025 x23: ffffffc010b8d000 x22: ffffffc010e3d000 x21: 0000000080de9000 x20: ffffff7f80000f90 x19: fffffffefe43c000 x18: 0000000000000030 x17: 0000000000001400 x16: 0000000000001c00 x15: ffffffc010cef1b8 x14: ffffffffffffffff x13: ffffffc010df1f40 x12: ffffffc010df1b70 x11: ffffffc010ce3b30 x10: ffffffc010ce3b30 x9 : 00000000ffffffc8 x8 : 0000000000000000 x7 : 000000000000000f x6 : ffffffc010df16e8 x5 : 0000000000000000 x4 : 0000000000000000 x3 : 00000000ffffffff x2 : 0000000000000000 x1 : 0000008080000000 x0 : ffffffc010af1d68 Call trace:  show_pte+0x12c/0x1b4  die_kernel_fault+0x54/0x78  __do_kernel_fault+0x11c/0x128  do_translation_fault+0x58/0xac  do_mem_abort+0x50/0xb0  el1_da+0x1c/0x90  __create_pgd_mapping+0x348/0x598  paging_init+0x3f0/0x70d0  setup_arch+0x2c0/0x5d4  start_kernel+0x94/0x49c Code: 92748eb5 900052a0 9135a000 cb010294 (f8756a96)  Signed-off-by: Marek Bykowski --- drivers/of/fdt.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c index 7bc92923104c..5f18c175dd78 100644 --- a/drivers/of/fdt.c +++ b/drivers/of/fdt.c @@ -936,6 +936,8 @@ static void __init early_init_dt_check_for_initrd(unsigned long node) if (!prop) return; end = of_read_number(prop, len/4); + if (!end) + return; __early_init_dt_declare_initrd(start, end); phys_initrd_start = start;