Re: [PATCH 1/4] kprobes: adjust kprobe addr for KPROBES_ON_FTRACE

["Naveen N. Rao" <naveen.n.rao@linux.ibm.com>]

Jisheng Zhang wrote:
> For KPROBES_ON_FTRACE case, we need to adjust the kprobe's addr
> correspondingly.
> 
> Signed-off-by: Jisheng Zhang <Jisheng.Zhang@synaptics.com>
> ---
>  kernel/kprobes.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/kernel/kprobes.c b/kernel/kprobes.c
> index 9873fc627d61..f8400753a8a9 100644
> --- a/kernel/kprobes.c
> +++ b/kernel/kprobes.c
> @@ -1560,6 +1560,9 @@ int register_kprobe(struct kprobe *p)
>  	addr = kprobe_addr(p);
>  	if (IS_ERR(addr))
>  		return PTR_ERR(addr);
> +#ifdef CONFIG_KPROBES_ON_FTRACE
> +	addr = (kprobe_opcode_t *)ftrace_call_adjust((unsigned long)addr);
> +#endif
>  	p->addr = addr;

I'm not sure what this is achieving, but looks wrong to me.

If you intend to have kprobes default to using ftrace entry for probing 
functions, consider over-riding kprobe_lookup_name() -- see powerpc 
variant for example.


- Naveen