linux-kernel - Re: [PATCH] cfq: fix IOPRIO_CLASS

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: <20071106192611.GS1767@kernel.dk>
Date:	Tue, 6 Nov 2007 20:26:11 +0100
From:	Jens Axboe <jens.axboe@...cle.com>
To:	Oleg Nesterov <oleg@...sign.ru>
Cc:	Andrew Morton <akpm@...ux-foundation.org>, Nick <gentuu@...il.com>,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] cfq: fix IOPRIO_CLASS_IDLE delays

On Tue, Nov 06 2007, Oleg Nesterov wrote:
> After the fresh boot:
> 
> 	ionice -c3 -p $$
> 	echo cfq >> /sys/block/XXX/queue/scheduler
> 	dd if=/dev/XXX of=/dev/null bs=512 count=1
> 
> Now dd hangs in D state and the queue is completely stalled for approximately
> INITIAL_JIFFIES + CFQ_IDLE_GRACE jiffies. This is because cfq_init_queue()
> forgets to initialize cfq_data->last_end_request.

Another good catch, thanks Oleg!

> (I guess this patch is not complete, overflow is still possible)

Hmm, where would it overflow?

-- 
Jens Axboe

-
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/