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Date: Mon, 17 Mar 1997 22:46:15 +1100
From: Bruce Evans <bde@zeta.org.au>
Message-Id: <199703171146.WAA09824@godzilla.zeta.org.au>
To: jlemon@americantv.com, sef@Kithrup.COM
Subject: Re: Gotcha in moving to post 4.4 lite2 merge ``world''.
Cc: current@FreeBSD.org
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>What's happening (in the test case I'm working on) is that the vm86() 
>process is going into an infinite loop, and somehow or the other, an AST
>interrupt is not being generated.
>
>Interrupts are enabled, the kernel is getting called, the AST flag in 
>_ipending is set, but when _doreti gets hit, it just jumps back into vm86
>mode instead of calling trap().  Right now, I can recover by writing
>a garbage %ds on the frame, and forcing a call into trap() via a doreti fault.

This means that the new cpl still masks ASTs (it should be 0 for return to
user mode) or maybe that the phantom AST test isn't working because the
stack frame is unusual.

Bruce