linux-kernel - Re: [BUG] fatal hang untarring 90GB file, possibly writeback related.

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: <1303923000.2583.8.camel@mulgrave.site>
Date:	Wed, 27 Apr 2011 11:50:00 -0500
From:	James Bottomley <James.Bottomley@...senPartnership.com>
To:	Chris Mason <chris.mason@...cle.com>
Cc:	linux-fsdevel <linux-fsdevel@...r.kernel.org>,
	linux-mm <linux-mm@...ck.org>,
	linux-kernel <linux-kernel@...r.kernel.org>
Subject: Re: [BUG] fatal hang untarring 90GB file, possibly writeback
 related.

On Wed, 2011-04-27 at 12:33 -0400, Chris Mason wrote:
> Probably easier to debug with a sysrq-l and sysrq-w. 

Yes, just enabling them for the repro ... I didn't echo 1
> /proc/sys/kernel/sysrq first time around

>  If you get stuck
> on the filesystem, it is probably waiting on ram, which it probably
> can't get because kswapd is spinning.  Eventually everyone backs up
> waiting for the transaction that never ends.  If we're really lucky it
> is just GFP_KERNEL where it should NOFS.
> 
> Since you're often stuck in different spots inside shrink_slab, we're
> probably not stuck on a lock.  But, trying with lock debugging, lockdep
> enabled and preempt on is a good idea to rule out locking mistakes.
> 
> Does the fedora debug kernel enable preempt?

No ... I've taken the Fedora 15 kernel config directly from their
install CD for this (with a bit of munging to get it to work on -rc4)

James


--
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/