linux-kernel - Re: [RFC PATCH(Experimental) 0/4] Freezer based Cpu-hotplug

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:	Sun, 18 Feb 2007 02:47:28 +0300
From:	Oleg Nesterov <oleg@...sign.ru>
To:	"Rafael J. Wysocki" <rjw@...k.pl>
Cc:	ego@...ibm.com, akpm@...l.org, paulmck@...ibm.com, mingo@...e.hu,
	vatsa@...ibm.com, dipankar@...ibm.com,
	venkatesh.pallipadi@...el.com, linux-kernel@...r.kernel.org,
	Pavel Machek <pavel@....cz>
Subject: Re: [RFC PATCH(Experimental) 0/4] Freezer based Cpu-hotplug

On 02/18, Oleg Nesterov wrote:
>
> On 02/17, Rafael J. Wysocki wrote:
> >
> > Alternatively, we can move the check into refrigerator(), like this:
> > 
> > --- linux-2.6.20-git13.orig/kernel/power/process.c
> > +++ linux-2.6.20-git13/kernel/power/process.c
> > @@ -39,6 +39,11 @@ void refrigerator(void)
> >  	/* Hmm, should we be allowed to suspend when there are realtime
> >  	   processes around? */
> >  	long save;
> > +
> > +	/* Freeze the task unless there is a vfork completion pending */
> > +	if (current->vfork_done)
> > +		return;
> > +
> 
> This means that "current" returns to user space (get_signal_to_deliver
> will clear TIF_SIGPENDING) and runs. While try_to_freeze_tasks() thinks
> it is frozen.

Ah, sorry. I am wrong, current has no PF_FROZEN yet.

However, this means that sys_vfork() makes impossible to freeze processes
until child exits/execs. Not good.

Oleg.

-
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/