From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754010AbcHQHY3 (ORCPT ); Wed, 17 Aug 2016 03:24:29 -0400 Received: from mx1.redhat.com ([209.132.183.28]:52066 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753698AbcHQHY2 (ORCPT ); Wed, 17 Aug 2016 03:24:28 -0400 Date: Wed, 17 Aug 2016 15:24:20 +0800 From: Dave Young To: Xunlei Pang Cc: linux-kernel@vger.kernel.org, kexec@lists.infradead.org, akpm@linux-foundation.org, ebiederm@xmission.com, Vivek Goyal , Baoquan He Subject: Re: [PATCH v2 2/2] kexec: Consider crashk_low_res in sanity_check_segment_list() Message-ID: <20160817072420.GD5498@dhcp-128-65.nay.redhat.com> References: <1471398657-20237-1-git-send-email-xlpang@redhat.com> <1471398657-20237-2-git-send-email-xlpang@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1471398657-20237-2-git-send-email-xlpang@redhat.com> User-Agent: Mutt/1.6.2 (2016-07-01) X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.26]); Wed, 17 Aug 2016 07:24:28 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, Xunlei, On 08/17/16 at 09:50am, Xunlei Pang wrote: > We have crashk_res only in most cases, but sometimes we have > crashk_low_res. > > For example, on 64-bit x86 systems, when "crashkernel=32M,high" > combined with "crashkernel=128M,low" is used, so some segments > may have the chance to be loaded into crashk_low_res area. We > can't fail it as a memory violation in these cases. > > Thus, we add the case to regard the segment as valid if it is > within crashk_low_res. crashkernel low is meant for swiotlb, it can be reserved automaticlly in case there's only crashkernel high specified in cmdline, I'm not sure it is useful to use crashk_res_low for other purpose and likely kdump can fail in the case. I'm not sure it is really necessary to add this check now, we may handle it only when there is an actual use case and bug report in the future. Thanks Dave > > Signed-off-by: Xunlei Pang > --- > kernel/kexec_core.c | 11 ++++++++--- > 1 file changed, 8 insertions(+), 3 deletions(-) > > diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c > index 707d18e..9012a60 100644 > --- a/kernel/kexec_core.c > +++ b/kernel/kexec_core.c > @@ -248,9 +248,14 @@ int sanity_check_segment_list(struct kimage *image) > mstart = image->segment[i].mem; > mend = mstart + image->segment[i].memsz - 1; > /* Ensure we are within the crash kernel limits */ > - if ((mstart < phys_to_boot_phys(crashk_res.start)) || > - (mend > phys_to_boot_phys(crashk_res.end))) > - return -EADDRNOTAVAIL; > + if ((mstart >= phys_to_boot_phys(crashk_res.start)) && > + (mend <= phys_to_boot_phys(crashk_res.end))) > + continue; > + if ((mstart >= phys_to_boot_phys(crashk_low_res.start)) && > + (mend <= phys_to_boot_phys(crashk_low_res.end))) > + continue; > + > + return -EADDRNOTAVAIL; > } > } > > -- > 1.8.3.1 >