From patchwork Mon Feb 24 16:30:55 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Laurent Dufour X-Patchwork-Id: 323688 Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from ozlabs.org (localhost [IPv6:::1]) by ozlabs.org (Postfix) with ESMTP id 615D72C02FA for ; Tue, 25 Feb 2014 03:32:08 +1100 (EST) Received: from e06smtp13.uk.ibm.com (e06smtp13.uk.ibm.com [195.75.94.109]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id A5B9C2C00C6 for ; Tue, 25 Feb 2014 03:31:05 +1100 (EST) Received: from /spool/local by e06smtp13.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Mon, 24 Feb 2014 16:30:59 -0000 Received: from d06dlp01.portsmouth.uk.ibm.com (9.149.20.13) by e06smtp13.uk.ibm.com (192.168.101.143) with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted; Mon, 24 Feb 2014 16:30:57 -0000 Received: from b06cxnps4074.portsmouth.uk.ibm.com (d06relay11.portsmouth.uk.ibm.com [9.149.109.196]) by d06dlp01.portsmouth.uk.ibm.com (Postfix) with ESMTP id 9E10017D8047 for ; Mon, 24 Feb 2014 16:31:29 +0000 (GMT) Received: from d06av09.portsmouth.uk.ibm.com (d06av09.portsmouth.uk.ibm.com [9.149.37.250]) by b06cxnps4074.portsmouth.uk.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id s1OGUjUL62783554 for ; Mon, 24 Feb 2014 16:30:45 GMT Received: from d06av09.portsmouth.uk.ibm.com (localhost [127.0.0.1]) by d06av09.portsmouth.uk.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id s1OGUuQP022541 for ; Mon, 24 Feb 2014 09:30:56 -0700 Received: from [127.0.1.1] (icon-9-164-175-210.megacenter.de.ibm.com [9.164.175.210]) by d06av09.portsmouth.uk.ibm.com (8.14.4/8.14.4/NCO v10.0 AVin) with ESMTP id s1OGUtEe022513; Mon, 24 Feb 2014 09:30:55 -0700 Subject: [PATCH] powerpc/crashdump : fix page frame number check in copy_oldmem_page To: Benjamin Herrenschmidt , Paul Mackerras , linuxppc-dev@lists.ozlabs.org From: Laurent Dufour Date: Mon, 24 Feb 2014 17:30:55 +0100 Message-ID: <20140224163055.7263.86979.stgit@nimbus> User-Agent: StGit/0.16 MIME-Version: 1.0 X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 14022416-2966-0000-0000-00000A62DBFE X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.16 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" In copy_oldmem_page, the current check using max_pfn and min_low_pfn to decide if the page is backed or not, is not valid when the memory layout is not continuous. This happens when running as a QEMU/KVM guest, where RTAS is mapped higher in the memory. In that case max_pfn points to the end of RTAS, and a hole between the end of the kdump kernel and RTAS is not backed by PTEs. As a consequence, the kdump kernel is crashing in copy_oldmem_page when accessing in a direct way the pages in that hole. This fix relies on the memblock's service memblock_is_region_memory to check if the read page is part or not of the directly accessible memory. Signed-off-by: Laurent Dufour Tested-by: Mahesh Salgaonkar --- arch/powerpc/kernel/crash_dump.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/arch/powerpc/kernel/crash_dump.c b/arch/powerpc/kernel/crash_dump.c index 11c1d06..7a13f37 100644 --- a/arch/powerpc/kernel/crash_dump.c +++ b/arch/powerpc/kernel/crash_dump.c @@ -98,17 +98,19 @@ ssize_t copy_oldmem_page(unsigned long pfn, char *buf, size_t csize, unsigned long offset, int userbuf) { void *vaddr; + phys_addr_t paddr; if (!csize) return 0; csize = min_t(size_t, csize, PAGE_SIZE); + paddr = pfn << PAGE_SHIFT; - if ((min_low_pfn < pfn) && (pfn < max_pfn)) { - vaddr = __va(pfn << PAGE_SHIFT); + if (memblock_is_region_memory(paddr, csize)) { + vaddr = __va(paddr); csize = copy_oldmem_vaddr(vaddr, buf, csize, offset, userbuf); } else { - vaddr = __ioremap(pfn << PAGE_SHIFT, PAGE_SIZE, 0); + vaddr = __ioremap(paddr, PAGE_SIZE, 0); csize = copy_oldmem_vaddr(vaddr, buf, csize, offset, userbuf); iounmap(vaddr); }