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Re: [Xen-devel] Xen scheduling bug?

On 15 Jul 2006, at 16:38, Stephen C. Tweedie wrote:

Note the marked lines --- Xen is turning irqs _off_ at this point, when
non-Xen is turning them on.  I just noticed it when merging the
irqtracing code.


Definitely -- we shouldn't enter schedule() with interrupts disabled. I think entry-xen.S needs an audit for this kind of thing. Just a few lines above this bug we XEN_UNBLOCK_EVENTS() where we shouldn't (race to userspace against schedule/signals), and that's probably unnecessary since we will return to userspace via the IRET hypercall which will safely atomically reenable interrupts anyway.

I haven't currently time to patch and test these problems -- if you can do it quicker and post a patch that would be very handy.


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