kprobes problem

[William Cohen]

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