From: "H. Peter Anvin" <hpa@zytor.com>
To: Vivek Goyal <vgoyal@redhat.com>
Cc: Baoquan He <bhe@redhat.com>,
Kexec Mailing List <kexec@lists.infradead.org>,
linux kernel mailing list <linux-kernel@vger.kernel.org>,
HATAYAMA Daisuke <d.hatayama@jp.fujitsu.com>,
"Eric W. Biederman" <ebiederm@xmission.com>,
Dave Young <dyoung@redhat.com>, WANG Chao <chaowang@redhat.com>
Subject: Re: /proc/vmcore mmap() failure issue
Date: Wed, 13 Nov 2013 15:08:22 -0800 [thread overview]
Message-ID: <52840666.5070800@zytor.com> (raw)
In-Reply-To: <20131113230056.GA19663@redhat.com>
On 11/13/2013 03:00 PM, Vivek Goyal wrote:
> I think it should be easy to truncate ELF headers in kexec-tools too when
> we are preparing elf headers. I am not sure if it is right thing to do or
> not. If some entry is showing up in /proc/iomem as RAM, then kexec-tools
> need to believe that it is a possibility that kernel is using that pfn and
> that pfn needs to be dumped out in vmcore. IMHO, kernel should fix this
> issue.
The kernel will never use a fractional page, so that is not an issue.
> Secondly, I am writing in-kernel kexec support too and I prepare ELF
> headers there too. And I am facing the same problem there too. So if
> we truncate partial pages in e820 both kexec-tools and in kernel kexec
> implementation don't have to do anything.
I'm mostly worried about truncation upon truncation causing problems.
As long as the trimming is done once and with proper consideration for
abutting regions, I guess I'm okay with it, although it feels wrong to me.
-hpa
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WARNING: multiple messages have this Message-ID (diff)
From: "H. Peter Anvin" <hpa@zytor.com>
To: Vivek Goyal <vgoyal@redhat.com>
Cc: linux kernel mailing list <linux-kernel@vger.kernel.org>,
HATAYAMA Daisuke <d.hatayama@jp.fujitsu.com>,
Kexec Mailing List <kexec@lists.infradead.org>,
Baoquan He <bhe@redhat.com>, WANG Chao <chaowang@redhat.com>,
Dave Young <dyoung@redhat.com>,
"Eric W. Biederman" <ebiederm@xmission.com>
Subject: Re: /proc/vmcore mmap() failure issue
Date: Wed, 13 Nov 2013 15:08:22 -0800 [thread overview]
Message-ID: <52840666.5070800@zytor.com> (raw)
In-Reply-To: <20131113230056.GA19663@redhat.com>
On 11/13/2013 03:00 PM, Vivek Goyal wrote:
> I think it should be easy to truncate ELF headers in kexec-tools too when
> we are preparing elf headers. I am not sure if it is right thing to do or
> not. If some entry is showing up in /proc/iomem as RAM, then kexec-tools
> need to believe that it is a possibility that kernel is using that pfn and
> that pfn needs to be dumped out in vmcore. IMHO, kernel should fix this
> issue.
The kernel will never use a fractional page, so that is not an issue.
> Secondly, I am writing in-kernel kexec support too and I prepare ELF
> headers there too. And I am facing the same problem there too. So if
> we truncate partial pages in e820 both kexec-tools and in kernel kexec
> implementation don't have to do anything.
I'm mostly worried about truncation upon truncation causing problems.
As long as the trimming is done once and with proper consideration for
abutting regions, I guess I'm okay with it, although it feels wrong to me.
-hpa
next prev parent reply other threads:[~2013-11-13 23:08 UTC|newest]
Thread overview: 60+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-11-13 20:41 /proc/vmcore mmap() failure issue Vivek Goyal
2013-11-13 20:41 ` Vivek Goyal
2013-11-13 21:04 ` Vivek Goyal
2013-11-13 21:04 ` Vivek Goyal
2013-11-13 21:14 ` H. Peter Anvin
2013-11-13 21:14 ` H. Peter Anvin
2013-11-13 22:41 ` Vivek Goyal
2013-11-13 22:41 ` Vivek Goyal
2013-11-13 22:44 ` H. Peter Anvin
2013-11-13 22:44 ` H. Peter Anvin
2013-11-13 23:00 ` Vivek Goyal
2013-11-13 23:00 ` Vivek Goyal
2013-11-13 23:08 ` H. Peter Anvin [this message]
2013-11-13 23:08 ` H. Peter Anvin
2013-11-14 10:31 ` HATAYAMA Daisuke
2013-11-14 10:31 ` HATAYAMA Daisuke
2013-11-14 15:13 ` Vivek Goyal
2013-11-14 15:13 ` Vivek Goyal
2013-11-15 9:41 ` HATAYAMA Daisuke
2013-11-15 9:41 ` HATAYAMA Daisuke
2013-11-15 14:26 ` Vivek Goyal
2013-11-15 14:26 ` Vivek Goyal
2013-11-18 0:51 ` Atsushi Kumagai
2013-11-18 0:51 ` Atsushi Kumagai
2013-11-18 13:55 ` Vivek Goyal
2013-11-18 13:55 ` Vivek Goyal
2013-11-20 5:29 ` Atsushi Kumagai
2013-11-20 5:29 ` Atsushi Kumagai
2013-11-20 14:59 ` Vivek Goyal
2013-11-20 14:59 ` Vivek Goyal
2013-11-21 5:00 ` Atsushi Kumagai
2013-11-21 5:00 ` Atsushi Kumagai
2013-11-21 8:31 ` HATAYAMA Daisuke
2013-11-21 8:31 ` HATAYAMA Daisuke
2013-11-21 16:52 ` Vivek Goyal
2013-11-21 16:52 ` Vivek Goyal
2013-11-25 8:10 ` Atsushi Kumagai
2013-11-25 8:10 ` Atsushi Kumagai
2013-11-25 9:01 ` HATAYAMA Daisuke
2013-11-25 9:01 ` HATAYAMA Daisuke
2013-11-25 14:41 ` Vivek Goyal
2013-11-25 14:41 ` Vivek Goyal
2013-11-26 1:51 ` Atsushi Kumagai
2013-11-26 1:51 ` Atsushi Kumagai
2013-11-26 5:16 ` HATAYAMA Daisuke
2013-11-26 5:16 ` HATAYAMA Daisuke
2013-11-19 9:55 ` HATAYAMA Daisuke
2013-11-19 9:55 ` HATAYAMA Daisuke
2013-11-20 5:27 ` Atsushi Kumagai
2013-11-20 5:27 ` Atsushi Kumagai
2013-11-20 6:43 ` HATAYAMA Daisuke
2013-11-20 6:43 ` HATAYAMA Daisuke
2013-11-26 1:52 ` Atsushi Kumagai
2013-11-26 1:52 ` Atsushi Kumagai
2013-11-21 7:14 ` chaowang
2013-11-21 7:14 ` chaowang
2013-11-25 8:09 ` Atsushi Kumagai
2013-11-25 8:09 ` Atsushi Kumagai
2013-11-26 3:29 ` chaowang
2013-11-26 3:29 ` chaowang
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