linux-kernel - Re: nfsd, v4: oops in find_acceptable_alias, ppc32 Linux, post-2.6.27-rc1

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]

Message-Id: <1218004178.24157.226.camel@pasglop>
Date:	Wed, 06 Aug 2008 16:29:38 +1000
From:	Benjamin Herrenschmidt <benh@...nel.crashing.org>
To:	Paul Collins <paul@...ly.ondioline.org>
Cc:	"J. Bruce Fields" <bfields@...ldses.org>,
	Neil Brown <neilb@...e.de>, nfsv4@...ux-nfs.org,
	linux-kernel@...r.kernel.org, linuxppc-dev@...abs.org
Subject: Re: nfsd, v4: oops in find_acceptable_alias, ppc32 Linux,
	post-2.6.27-rc1

On Tue, 2008-08-05 at 17:16 +1000, Benjamin Herrenschmidt wrote:
> On Tue, 2008-08-05 at 16:47 +1200, Paul Collins wrote:
> > It's about four years old.  It was in storage for about six months and I
> > got it repaired a few weeks ago (display cable and inverter).  The sort
> > of crazy crap I've been reporting certainly smacks of memory corruption.
> > But on the other hand, 2.6.25 (Debian's) and 2.6.26 (my own) have been
> > trouble-free.
> 
> Any chance you can bisect the problem ?

Ok, so I can reproduce on a few 32 bits configs with ftrace enabled.

Looks like some non volatile GPRs get corrupted. I don't know yet if
ftrace is the culprit though, I couldn't find anything obviously wrong
with the mcount implementation we have.

It looks like the corrupted GPR has been saved/restored on the stack
and that the corruption is due to the stack itself being written
to. It's not clear by whome though and in what circumstances.

We'll have to dig more.

Cheers,
Ben.


--
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/