linux-kernel - Re: kswapd hung tasks in 2.6.38-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: <1296513616.7797.4929.camel@nimitz>
Date:	Mon, 31 Jan 2011 14:40:16 -0800
From:	Dave Hansen <dave@...ux.vnet.ibm.com>
To:	CAI Qian <caiqian@...hat.com>
Cc:	linux-mm <linux-mm@...ck.org>, linux-kernel@...r.kernel.org,
	aarcange <aarcange@...hat.com>
Subject: Re: kswapd hung tasks in 2.6.38-rc1

On Mon, 2011-01-31 at 12:58 -0800, Dave Hansen wrote:
> On Thu, 2011-01-20 at 03:55 -0500, CAI Qian wrote:
> > When running LTP oom01 [1] testing, the allocation process stopped
> > processing right after starting to swap.
> 
> I'm seeing the same stuff, but on -rc2.  I thought it was
> transparent-hugepage-related, but I don't see much of a trace of it in
> the stack dumps.
> 
> http://sr71.net/~dave/ibm/config-v2.6.38-rc2
> 
> It happened to me as well around the time that things started to hit
> swap.

Still not a very good data point, but I ran a heavy swap load for an
hour or so without reproducing this.  But, it happened again after I
enabled transparent huge pages.  I managed to get a sysrq-t dump out of
it:

	http://sr71.net/~dave/ibm/2.6.38-rc2-hang-0.txt

khugepaged is one of the three running tasks.  Note, I set both its
sleep timeouts to zero to stress it out a bit.

I'll keep trying to reproduce without THP.

-- Dave

--
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/