Messages in this thread | | | Subject | Re: ptrace in 2.6.5 | From | Andi Kleen <> | Date | Mon, 10 May 2004 20:49:39 +0200 |
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Fabiano Ramos <ramos_fabiano@yahoo.com.br> writes:
> Hi All. > > Is ptrace(), in singlestep mode, required to stop after a int 0x80? > When tracing a sequence like > > mov ... > int 0x80 > mov .... > > ptrace would notify the tracer after the two movs, but not after the > int 0x80. I want to know if it is a bug or the expected behaviour.
What happens is that after the int 0x80 the CPU is in ring 0 (you don't get an trace event in that mode unless you use a kernel debugger). Then when the kernel returns the last instruction executed before it is an IRET. But the IRET is also executed still in ring 0 and you should not get an event for it (you can not even access its code from user space).
So it's expected behaviour.
-Andi
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