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Date: Mon, 3 Mar 2003 14:15:32 -0500 (EST)
From: Nicolas Pitre <nico@cam.org>
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To: Alan Cox <alan@lxorguk.ukuu.org.uk>
cc: Linus Torvalds <torvalds@transmeta.com>,
       lkml <linux-kernel@vger.kernel.org>
Subject: Re: [patch] small tty irq race fix
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On 3 Mar 2003, Alan Cox wrote:

> 
> > 		fp = tty->flip.flag_buf + TTY_FLIPBUF_SIZE;
> > -		tty->flip.buf_num = 0;
> >  
> >  		local_irq_save(flags); // FIXME: is this safe?
> > +		tty->flip.buf_num = 0;
> 
> The other CPU can be touching these fields too surely. Its a
> useful note that the spinlocks need putting in the right spot
> but its still broken 8(

Well I only care about UP at the moment and the patch makes it right for UP
at least.  Someone with his brain around the tty locking requirements can
look at replacing the local_irq_save() (there and elsewhere as well), which
is sort of a different issue.


Nicolas