From: Oleg Nesterov <oleg@tv-sign.ru>
To: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>,
linux-kernel <linux-kernel@vger.kernel.org>,
Prarit Bhargava <prarit@redhat.com>
Subject: Re: [RFC][PATCH] ->signal->tty locking
Date: Wed, 18 Oct 2006 21:21:03 +0400 [thread overview]
Message-ID: <20061018172103.GB2062@oleg> (raw)
In-Reply-To: <1161091781.24237.161.camel@localhost.localdomain>
On 10/17, Alan Cox wrote:
>
> Ar Maw, 2006-10-17 am 16:33 +0400, ysgrifennodd Oleg Nesterov:
> > I sent a patch,
> > http://marc.theaimsgroup.com/?l=linux-kernel&m=114268787415193
> >
> > but it was ignored. Probably I should re-send it.
>
> Definitely - we still see reports of tty slab scribbles
This patch can't fix anything, sorry for the confusion.
Yes, the 'if (new_sigh) {}' code in sys_unshare() is broken, but it is
never executed, because unshare_sighand() never populates new_sighp.
Probably it is better to just remove this code.
> > > Right, use tty_mutex when using the tty, use ->sighand when changing
> > > signal->tty.
> >
> > I think that things like do_task_stat()/do_acct_process() do not need
> > global tty_mutex, they can use ->siglock.
>
> Please keep the tty_mutex as it will protect against other stuff later.
> Once tty is a bit saner then someone brave can refcount it properly and
> that'll make it much prettier.
Oh, but it is silly to take the global tty_mutex in do_task_stat().
Why do we need it if ->siglock protects ->signal->tty ? We are only
reading the tty_struct, tty->driver can't go away ...
Oleg.
prev parent reply other threads:[~2006-10-18 17:21 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-10-16 9:53 [RFC][PATCH] ->signal->tty locking Peter Zijlstra
2006-10-16 13:39 ` Prarit Bhargava
2006-10-17 8:10 ` Oleg Nesterov
2006-10-17 10:17 ` Peter Zijlstra
2006-10-17 12:33 ` Oleg Nesterov
2006-10-17 13:00 ` Peter Zijlstra
2006-10-17 14:08 ` Alan Cox
2006-10-18 16:55 ` Oleg Nesterov
2006-10-17 13:29 ` Alan Cox
2006-10-18 17:21 ` Oleg Nesterov [this message]
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