linux-ext4 - Re: [PATCH][RFC]JBD2: Fix journal checksum kernel oops on NUMA

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, 02 Nov 2007 08:31:48 -0800
From:	Badari Pulavarty <pbadari@...il.com>
To:	Andreas Dilger <adilger@....com>
Cc:	Mingming Cao <cmm@...ibm.com>,
	Girish Shilamkar <girish@...sterfs.com>,
	Avantika Mathur <mathur@...ux.vnet.ibm.com>,
	ext4 <linux-ext4@...r.kernel.org>
Subject: Re: [PATCH][RFC]JBD2: Fix journal checksum kernel oops on NUMA

On Fri, 2007-11-02 at 13:20 +0800, Andreas Dilger wrote:
> On Nov 01, 2007  17:40 -0700, Mingming Cao wrote:
> > Current journal checksumming patch failed fsstress test on NUMA. The 
> > bh->b_data passed to the crc32_be () function could be NULL pointer, 
> > which caused kernel oops immediately when running fsstress with -o 
> > journal_checksum. It is because the page is part of highmem on NUMA box.
> > We need to kmap the page before access the bh->b_data to calculate
> > the checksums.
> 
> I have no objection to the patch, per-se, but I'm surprised that there
> would ever be a buffer head pointing at a page in high memory?  That
> seems contrary to what I would expect...

I was surprised to see that too while helping Mingming/Avantika track
this issue. I was under impression that we are checksumming only
metadata and it should be lowmem. But only "buffer_head"s are in lowmem.
Pages that point to can be in Highmem.

Thanks,
Badari

-
To unsubscribe from this list: send the line "unsubscribe linux-ext4" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html