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Re: kprobes problem

Richard J Moore wrote: 



I was certainly intended to. As I mentioned before there is specific code
to deal with call, jmp etc. Probing INT should be OK, though I don't think
a probe on INT3 works. Need to check.

I figured that INT3 wouldn't be probed. However, there are certainly some other INT instructions in the code. I saw them (and the IRET) in the disassembled code. I was just figuring if we are fixing up the RET that we take a moment and make sure there are no other omissions.

-Will

- -
Richard J Moore
IBM Advanced Linux Response Team - Linux Technology Centre
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William Cohen <wcohen@redhat. com> To Sent by: prasanna@in.ibm.com systemtap-owner cc @sources.redhat Baruch Even <baruch@ev-en.org>, .com systemtap@sources.redhat.com, maneesh@in.ibm.com, varap@us.ibm.com bcc 14/03/2005 16:53 Subject Re: kprobes problem




Prasanna S Panchamukhi wrote:

Hi Baruch,

Thanks for pointing it out.
Yes, kprobes could not handle probes on ret/lret instruction.
The instruction pointer modification in case of ret/lret
instrcution is not required.
The below patch should fix the problem. This patch is for i386
achitecture and soon will be ported to other architectures.

Please let me know if you have any issues. 


Are there any other instruction that will cause a control flow change?
e.g. "int" and "IRET" instructions? There are certainly places "int" is
used in the kernel. Does the kprobes code account for all the control
flow instructions?

-Wil

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