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=-14.8 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS 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 D3E93C433E4 for ; Thu, 6 Aug 2020 23:38:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E15762173E for ; Thu, 6 Aug 2020 23:38:52 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="xalOR3qj"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="KWKnFpe0" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726518AbgHFXiv (ORCPT ); Thu, 6 Aug 2020 19:38:51 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49956 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726446AbgHFXis (ORCPT ); Thu, 6 Aug 2020 19:38:48 -0400 Received: from galois.linutronix.de (Galois.linutronix.de [IPv6:2a0a:51c0:0:12e:550::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A0288C061575; Thu, 6 Aug 2020 16:38:47 -0700 (PDT) Date: Thu, 06 Aug 2020 23:38:45 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1596757126; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=z9Ue43woZ8D4rqkM2savDZbJ72Y/T7d229UG6PhY8aY=; b=xalOR3qjDzjU+60DE5Ncb/hcpCmycT0hCQBYUiylwKqYf4oYOL/3pNNStaHtJzkgbwADhb rdt4BW049AYzFOKW9Q+/s5i9wSh03ukVAlS7Vq6mXkztvn0hSiCyu+ellF6Ym/1d+akVGR cQP5F69uD6CA741/m1Nttcchd/AV+m8SIzBXL6OFQQLB+MHS6/aN+6xp3/t8OVBpqs7cOz cN/kCz4WKseh6dNwPDJD+mN4LkeumVY5UneUaw6sKIyhuv921D2SCxjDCDePi6h1PjOybV 7VgzbkN5l7IVedCvMnYEwpCmuQh9SNkQ9tbJcXKH9sDXy/I29Xuk0j9pS04w0w== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1596757126; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=z9Ue43woZ8D4rqkM2savDZbJ72Y/T7d229UG6PhY8aY=; b=KWKnFpe0c1kiJbTDbX2ofVQQa9mtcGVmTTPgz2iMEBGUwd/UQupCYYg5AaaWLwurM5hm03 L5EffIyKZqqa2UCQ== From: "tip-bot2 for Lianbo Jiang" Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: x86/urgent] kexec: Improve & fix crash_exclude_mem_range() to handle overlapping ranges Cc: Lianbo Jiang , Ingo Molnar , Dave Young , x86 , LKML In-Reply-To: <20200804044933.1973-3-lijiang@redhat.com> References: <20200804044933.1973-3-lijiang@redhat.com> MIME-Version: 1.0 Message-ID: <159675712551.3192.12580323295700287639.tip-bot2@tip-bot2> Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The following commit has been merged into the x86/urgent branch of tip: Commit-ID: a2e9a95d2190ef55bf0724ecdf8a466d393a86b6 Gitweb: https://git.kernel.org/tip/a2e9a95d2190ef55bf0724ecdf8a466d393a86b6 Author: Lianbo Jiang AuthorDate: Tue, 04 Aug 2020 12:49:32 +08:00 Committer: Ingo Molnar CommitterDate: Fri, 07 Aug 2020 01:32:00 +02:00 kexec: Improve & fix crash_exclude_mem_range() to handle overlapping ranges The crash_exclude_mem_range() function can only handle one memory region a time. It will fail in the case in which the passed in area covers several memory regions. In this case, it will only exclude the first region, then return, but leave the later regions unsolved. E.g in a NEC system with two usable RAM regions inside the low 1M: ... BIOS-e820: [mem 0x0000000000000000-0x000000000003efff] usable BIOS-e820: [mem 0x000000000003f000-0x000000000003ffff] reserved BIOS-e820: [mem 0x0000000000040000-0x000000000009ffff] usable It will only exclude the memory region [0, 0x3efff], the memory region [0x40000, 0x9ffff] will still be added into /proc/vmcore, which may cause the following failure when dumping vmcore: ioremap on RAM at 0x0000000000040000 - 0x0000000000040fff WARNING: CPU: 0 PID: 665 at arch/x86/mm/ioremap.c:186 __ioremap_caller+0x2c7/0x2e0 ... RIP: 0010:__ioremap_caller+0x2c7/0x2e0 ... cp: error reading '/proc/vmcore': Cannot allocate memory kdump: saving vmcore failed In order to fix this bug, let's extend the crash_exclude_mem_range() to handle the overlapping ranges. [ mingo: Amended the changelog. ] Signed-off-by: Lianbo Jiang Signed-off-by: Ingo Molnar Acked-by: Dave Young Link: https://lore.kernel.org/r/20200804044933.1973-3-lijiang@redhat.com --- kernel/kexec_file.c | 35 +++++++++++++++++++++++------------ 1 file changed, 23 insertions(+), 12 deletions(-) diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c index 94661d2..97fa682 100644 --- a/kernel/kexec_file.c +++ b/kernel/kexec_file.c @@ -1157,24 +1157,26 @@ int crash_exclude_mem_range(struct crash_mem *mem, unsigned long long mstart, unsigned long long mend) { int i, j; - unsigned long long start, end; + unsigned long long start, end, p_start, p_end; struct crash_mem_range temp_range = {0, 0}; for (i = 0; i < mem->nr_ranges; i++) { start = mem->ranges[i].start; end = mem->ranges[i].end; + p_start = mstart; + p_end = mend; if (mstart > end || mend < start) continue; /* Truncate any area outside of range */ if (mstart < start) - mstart = start; + p_start = start; if (mend > end) - mend = end; + p_end = end; /* Found completely overlapping range */ - if (mstart == start && mend == end) { + if (p_start == start && p_end == end) { mem->ranges[i].start = 0; mem->ranges[i].end = 0; if (i < mem->nr_ranges - 1) { @@ -1185,20 +1187,29 @@ int crash_exclude_mem_range(struct crash_mem *mem, mem->ranges[j].end = mem->ranges[j+1].end; } + + /* + * Continue to check if there are another overlapping ranges + * from the current position because of shifting the above + * mem ranges. + */ + i--; + mem->nr_ranges--; + continue; } mem->nr_ranges--; return 0; } - if (mstart > start && mend < end) { + if (p_start > start && p_end < end) { /* Split original range */ - mem->ranges[i].end = mstart - 1; - temp_range.start = mend + 1; + mem->ranges[i].end = p_start - 1; + temp_range.start = p_end + 1; temp_range.end = end; - } else if (mstart != start) - mem->ranges[i].end = mstart - 1; + } else if (p_start != start) + mem->ranges[i].end = p_start - 1; else - mem->ranges[i].start = mend + 1; + mem->ranges[i].start = p_end + 1; break; } @@ -1243,7 +1254,7 @@ int crash_prepare_elf64_headers(struct crash_mem *mem, int kernel_map, * kexec-tools creates an extra PT_LOAD phdr for kernel text mapping * area (for example, ffffffff80000000 - ffffffffa0000000 on x86_64). * I think this is required by tools like gdb. So same physical - * memory will be mapped in two elf headers. One will contain kernel + * memory will be mapped in two elf headers. One will contain kernel * text virtual addresses and other will have __va(physical) addresses. */ @@ -1270,7 +1281,7 @@ int crash_prepare_elf64_headers(struct crash_mem *mem, int kernel_map, ehdr->e_ehsize = sizeof(Elf64_Ehdr); ehdr->e_phentsize = sizeof(Elf64_Phdr); - /* Prepare one phdr of type PT_NOTE for each present cpu */ + /* Prepare one phdr of type PT_NOTE for each present CPU */ for_each_present_cpu(cpu) { phdr->p_type = PT_NOTE; notes_addr = per_cpu_ptr_to_phys(per_cpu_ptr(crash_notes, cpu));