* Oleg Nesterov <oleg@xxxxxxxxxx> [2011-11-30 19:57:51]:
> On 11/18, Srikar Dronamraju wrote:
> >
> > +static void handle_riprel_insn(struct mm_struct *mm, struct uprobe *uprobe,
> > + struct insn *insn)
> > +{
> > [...snip...]
> > + if (insn->immediate.nbytes) {
> > + cursor++;
> > + memmove(cursor, cursor + insn->displacement.nbytes,
> > + insn->immediate.nbytes);
> > + }
> > + return;
> > +}
>
> Of course I don not understand this code. But it seems that it can
> rewrite uprobe->insn ?
>
Yes, we do rewrite the instruction for the RIP relative instructions.
But the first byte is still intact.
> If yes, don't we need to save the original insn for unregister_uprobe?
When we unregister, we just put back the least opcode size which
happens to be the first byte for x86.
--
Thanks and Regards
Srikar
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