On 11/05, Namhyung Kim wrote:
>
> On Mon, 4 Nov 2013 19:57:54 +0100, Oleg Nesterov wrote:
> >>
> >> static void __user *get_user_vaddr(struct pt_regs *regs, unsigned long
> >> addr)
> >> {
> >> return (void __force __user *)addr + instruction_pointer(regs);
> >> }
> >>
> >> ?
> >>
> >> This should solve the problems with relocations/randomization/bss.
> >>
> >> The obvious disadvantage is that it is not easy to calculate the
> >> offset we need to pass as an argument, it depends on the probed
> >> function.
> >
> > forgot to mention... and instruction_pointer() can't work in ret-probe,
> > we need to pass the "unsigned long func" arg somehow...
>
> Hmm.. what's the value of tu->offset in this case? Does it have the
> offset of the return address or the start of the function?
It is the offest of function. IOW, it is the same regardless of
is_ret_probe().
Ignoring probes_seq_show() we only need it for uprobe_register().
(yes, it is also used in uprobe_unregister/apply, but this is only
because this API ugly and should be cleanuped).
Oleg.
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