linux-kernel - Re: [PATCH] kexec/powerpc: fix exporting memory limit

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Fri, 07 Mar 2014 11:47:38 +1100
From:	Michael Ellerman <mpe@...erman.id.au>
To:	Nikita Yushchenko <nyushchenko@....rtsoft.ru>
Cc:	kexec@...ts.infradead.org,
	Benjamin Herrenschmidt <benh@...nel.crashing.org>,
	Paul Mackerras <paulus@...ba.org>,
	Anton Blanchard <anton@...ba.org>,
	Hari Bathini <hbathini@...ux.vnet.ibm.com>,
	Mahesh Salgaonkar <mahesh@...ux.vnet.ibm.com>,
	linuxppc-dev@...ts.ozlabs.org, yadviga@....rtsoft.ru,
	lugovskoy@....rtsoft.ru, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] kexec/powerpc: fix exporting memory limit

On Thu, 2014-03-06 at 18:24 +0400, Nikita Yushchenko wrote:
> When preparing dump-capturing kernel, kexec userspace tool needs to know
> actual amount of memory used by the running kernel. This may differ from
> extire available DRAM for a couple of reasons. To address this issue,
> kdump kernel support code injects several attributes into device tree that
> are later captured by userspace kexec tool via /proc interface.
> 
> One such attrubute is 'chosen/linux,memory_limit' that is used to pass
> memory limit of the running kernel.
> 
> This was initialized using kernel's 'memory_limit' variable, that is set
> by early init code based on mem= kernel parameter and other reasons.
> 
> But there are cases when memory_limit variable does not contain proper
> information. One such case is when !CONFIG_HIGHMEM kernel runs on system
> with memory large enough not to fit into lowmem.

Why doesn't the !CONFIG_HIGHMEM code update memory_limit to reflect reality.

cheers


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/