linux-kernel - Re: [RFC/RFT PATCH v3] sched: automated per tty task groups

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:	Tue, 16 Nov 2010 20:31:48 -0500
From:	Kyle McMartin <kyle@...artin.ca>
To:	Mike Galbraith <efault@....de>
Cc:	Oleg Nesterov <oleg@...hat.com>,
	Peter Zijlstra <a.p.zijlstra@...llo.nl>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Markus Trippelsdorf <markus@...ppelsdorf.de>,
	Mathieu Desnoyers <mathieu.desnoyers@...icios.com>,
	Ingo Molnar <mingo@...e.hu>,
	LKML <linux-kernel@...r.kernel.org>
Subject: Re: [RFC/RFT PATCH v3] sched: automated per tty task groups

Hi Mike,

On Mon, Nov 15, 2010 at 02:25:50PM -0700, Mike Galbraith wrote:
> --- linux-2.6.orig/drivers/tty/tty_io.c
> +++ linux-2.6/drivers/tty/tty_io.c
> @@ -3160,6 +3160,7 @@ static void __proc_set_tty(struct task_s
>  	put_pid(tsk->signal->tty_old_pgrp);
>  	tsk->signal->tty = tty_kref_get(tty);
>  	tsk->signal->tty_old_pgrp = NULL;
> +	sched_autogroup_create_attach(tsk);
>  }
>  

This is a bit of a problem, as it's called in_atomic context and kmalloc's
under GFP_KERNEL (which can sleep.) This results in sleep-under-spinlock
prints when CONFIG_DEBUG_SPINLOCK_SLEEP=y.

I spent a bit of time thinking about how to fix that, but it's a bit
difficult because of the nested spin_lock_irq in that bit of the
tty_ioctl callchain.

I'll think about it some more tonight and follow-up if I can think of a
way to fix it.

regards, Kyle
--
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/