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RE: kprobe fault handling
- From: "Keshavamurthy, Anil S" <anil dot s dot keshavamurthy at intel dot com>
- To: "Jim Keniston" <jkenisto at us dot ibm dot com>, "Martin Hunt" <hunt at redhat dot com>
- Cc: "SystemTAP" <systemtap at sources dot redhat dot com>
- Date: Tue, 7 Feb 2006 12:35:57 -0800
- Subject: RE: kprobe fault handling
>I just had a long chat with Richard Moore about this whole topic. I
>agree with you on this, and I think Richard would, too.
>
>So unless there's a user-specified handler and that handler specifies
>(by returning 1) that it has handled the exception,
>kprobe_fault_handler() should run fixup_exception(), right?
>
>Now I'm looking, later in that function, at the code (on i386) where we
>handle an exception while single-stepping. I don't think
>resume_execution() is the right thing to do here. We haven't
>successfully executed the probed instruction, and the eip still points
>at that instruction, right? I think we're just hosed at this point.
>Comments?
I agree with your comments and we need a better fix.
Currently for RHEL4 release I am inclined to remove
DIE_PAGE_FAULT switch case as this at least improves
the performance.
-Anil