linux-kernel - Re: [PATCH 31/31] memblock: Add memblock_find_in

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:	Tue, 27 Jul 2010 23:38:03 -0700
From:	"H. Peter Anvin" <hpa@...or.com>
To:	Yinghai Lu <yinghai@...nel.org>
CC:	Benjamin Herrenschmidt <benh@...nel.crashing.org>,
	Ingo Molnar <mingo@...e.hu>,
	Thomas Gleixner <tglx@...utronix.de>,
	Andrew Morton <akpm@...ux-foundation.org>,
	David Miller <davem@...emloft.net>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Johannes Weiner <hannes@...xchg.org>,
	linux-kernel@...r.kernel.org, linux-arch@...r.kernel.org
Subject: Re: [PATCH 31/31] memblock: Add memblock_find_in_range()

On 07/27/2010 11:08 PM, Yinghai Lu wrote:
> 
> for example: 
> high/low allocation, from first kernel to kexec second kernel, always work fine except system with Qlogic card.
> because Qlogic card is using main RAM as EFT etc for card's FW log trace. second kernel have not idea that those RAM
>  is used by first kernel for that purpose. that the CARD still use that between two kernels.
> second kernel could have crash it try to use those ram.
> 

Uhm, no.  That's a bug in the Qlogic driver not shutting the card down
cleanly.  Hacking around that in memory allocation order is braindamaged
in the extreme.  kexec *cannot* be safe in any way if we don't shut down
pending DMA, and what you describe above is DMA.

> low/high allocation seems to be safe,  second kernel can slip to boot fine.

Low to high is just broken.  Low memory is a special, desirable
resource, and we should minimize the use of it.

	-hpa

-- 
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel.  I don't speak on their behalf.

--
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/