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Subject: Re: VM86 interrupt emulation breakage and FIXes for 2.6.x kernel
	series
From: Alan Cox <alan@lxorguk.ukuu.org.uk>
To: Pavel Pisa <pisa@cmp.felk.cvut.cz>
Cc: Ingo Molnar <mingo@redhat.com>,
       Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
       Linus Torvalds <torvalds@osdl.org>, trivial@rustcorp.com.au
In-Reply-To: <200412091459.51583.pisa@cmp.felk.cvut.cz>
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Date: Fri, 10 Dec 2004 21:05:33 +0000
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On Iau, 2004-12-09 at 13:59, Pavel Pisa wrote:
>   if (vm86_irqs[intno].sig)
>    send_sig(vm86_irqs[intno].sig, vm86_irqs[intno].tsk, 1);
>   /* else user will poll for IRQs */
> + spin_unlock_irqrestore(&irqbits_lock, flags); 
> + /* Next line would be required to handle correctly level activated 
> interrupts */
> + disable_irq(intno);
> + return IRQ_HANDLED;

You can't disable_irq and return to user space - the IRQ may be shared
by a device needed to make user space progress. 

The rest looks like a real bug.