Re: [Xen-devel] do_iret bug in xen

To:	xen-devel@xxxxxxxxxxxxxxxxxxx
Subject:	Re: [Xen-devel] do_iret bug in xen
From:	"Ashish Bijlani" <ashish.bijlani@xxxxxxxxx>
Date:	Tue, 27 Nov 2007 17:41:24 -0500
Delivery-date:	Tue, 27 Nov 2007 14:42:02 -0800
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"cpumask_raise_softirq(mask, SCHEDULE_SOFTIRQ)" sends an IPI to the target processor, this can cause current to change.

On Nov 27, 2007 4:50 PM, Andres Lagar-Cavilla < andreslc@xxxxxxxxxxxxxx> wrote:

raise_softirq is not the same as actually doing it. Raise only sets a
bit indicating pending softirq. Before returning to the guest, the bin
triggers actual execution of the softirq

Andres

since "sti" is on, an interrupt can occur which can cause the
control to enter "__runq_tickle", which then invokes
"cpumask_raise_softirq(mask, SCHEDULE_SOFTIRQ)" to send IPI to a
processor causing the control to enter "__enter_scheduler" which
changes the current.

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Re: [Xen-devel] do_iret bug in xen