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 E09C3C636CD for ; Tue, 7 Feb 2023 08:48:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229791AbjBGIsF (ORCPT ); Tue, 7 Feb 2023 03:48:05 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36410 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229847AbjBGIsE (ORCPT ); Tue, 7 Feb 2023 03:48:04 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A524630FB for ; Tue, 7 Feb 2023 00:48:03 -0800 (PST) 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 dfw.source.kernel.org (Postfix) with ESMTPS id 3F8E26121B for ; Tue, 7 Feb 2023 08:48:03 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3FB0EC433D2; Tue, 7 Feb 2023 08:48:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1675759682; bh=dvocRrxw34W1WLL/bP2S1kJoSMddN/Ev4TCsX8S/ykw=; h=Subject:To:Cc:From:Date:From; b=lMbxfWeUi0weyOkAZ11uA4OFHkupX/Ebd/PAKdGc/sH7vEiPQf7A+MwZG9dQ25X1I mR7H28ujOoFk2Xx5vpaT4B7/G684weLVi9nhNi1SsajtgPmuN6ZUZU0A4vlTm+KbbF t+5xw9V1uwNsK4jBms36iobtFwYOd520kmWsaxc8= Subject: FAILED: patch "[PATCH] powerpc/kexec_file: Fix division by zero in extra size" failed to apply to 5.15-stable tree To: mpe@ellerman.id.au Cc: From: Date: Tue, 07 Feb 2023 09:47:59 +0100 Message-ID: <167575967970206@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org The patch below does not apply to the 5.15-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . Possible dependencies: 7294194b47e9 ("powerpc/kexec_file: Fix division by zero in extra size estimation") 340a4a9f8773 ("powerpc: Take in account addition CPU node when building kexec FDT") thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 7294194b47e994753a86eee8cf1c61f3f36458a3 Mon Sep 17 00:00:00 2001 From: Michael Ellerman Date: Mon, 30 Jan 2023 12:47:07 +1100 Subject: [PATCH] powerpc/kexec_file: Fix division by zero in extra size estimation In kexec_extra_fdt_size_ppc64() there's logic to estimate how much extra space will be needed in the device tree for some memory related properties. That logic uses the size of RAM divided by drmem_lmb_size() to do the estimation. However drmem_lmb_size() can be zero if the machine has no hotpluggable memory configured, which is the case when booting with qemu and no maxmem=x parameter is passed (the default). The division by zero is reported by UBSAN, and can also lead to an overflow and a warning from kvmalloc, and kdump kernel loading fails: WARNING: CPU: 0 PID: 133 at mm/util.c:596 kvmalloc_node+0x15c/0x160 Modules linked in: CPU: 0 PID: 133 Comm: kexec Not tainted 6.2.0-rc5-03455-g07358bd97810 #223 Hardware name: IBM pSeries (emulated by qemu) POWER9 (raw) 0x4e1200 0xf000005 of:SLOF,git-dd0dca pSeries NIP: c00000000041ff4c LR: c00000000041fe58 CTR: 0000000000000000 REGS: c0000000096ef750 TRAP: 0700 Not tainted (6.2.0-rc5-03455-g07358bd97810) MSR: 800000000282b033 CR: 24248242 XER: 2004011e CFAR: c00000000041fed0 IRQMASK: 0 ... NIP kvmalloc_node+0x15c/0x160 LR kvmalloc_node+0x68/0x160 Call Trace: kvmalloc_node+0x68/0x160 (unreliable) of_kexec_alloc_and_setup_fdt+0xb8/0x7d0 elf64_load+0x25c/0x4a0 kexec_image_load_default+0x58/0x80 sys_kexec_file_load+0x5c0/0x920 system_call_exception+0x128/0x330 system_call_vectored_common+0x15c/0x2ec To fix it, skip the calculation if drmem_lmb_size() is zero. Fixes: 2377c92e37fe ("powerpc/kexec_file: fix FDT size estimation for kdump kernel") Cc: stable@vger.kernel.org # v5.12+ Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20230130014707.541110-1-mpe@ellerman.id.au diff --git a/arch/powerpc/kexec/file_load_64.c b/arch/powerpc/kexec/file_load_64.c index af8854f9eae3..19d084682bc2 100644 --- a/arch/powerpc/kexec/file_load_64.c +++ b/arch/powerpc/kexec/file_load_64.c @@ -989,10 +989,13 @@ unsigned int kexec_extra_fdt_size_ppc64(struct kimage *image) * linux,drconf-usable-memory properties. Get an approximate on the * number of usable memory entries and use for FDT size estimation. */ - usm_entries = ((memblock_end_of_DRAM() / drmem_lmb_size()) + - (2 * (resource_size(&crashk_res) / drmem_lmb_size()))); - - extra_size = (unsigned int)(usm_entries * sizeof(u64)); + if (drmem_lmb_size()) { + usm_entries = ((memblock_end_of_DRAM() / drmem_lmb_size()) + + (2 * (resource_size(&crashk_res) / drmem_lmb_size()))); + extra_size = (unsigned int)(usm_entries * sizeof(u64)); + } else { + extra_size = 0; + } /* * Get the number of CPU nodes in the current DT. This allows to