Re: [patch] x86_64 specific function return probes

[Andrew Morton <akpm@osdl.org>]

"Lynch, Rusty" <rusty.lynch@intel.com> wrote:
>
> 
> From: Andi Kleen [mailto:ak@suse.de]
> >On Thu, Jun 02, 2005 at 09:09:09AM -0700, Rusty Lynch wrote:
> >> The following patch adds the x86_64 architecture specific
> implementation
> >> for function return probes to the 2.6.12-rc5-mm2 kernel.
> >
> >This is not a sufficient description for a patch. Can you describe
> >how it actually works and what it does?
> >
> 
> Ok, let me write up a description and I'll repost.

You did, but:

> >> + * Called when we hit the probe point at kretprobe_trampoline
> >> + */
> >> +int trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs)
> >> +{
> >> +	struct task_struct *tsk;
> >> +	struct kretprobe_instance *ri;
> >> +	struct hlist_head *head;
> >> +	struct hlist_node *node;
> >> +	unsigned long *sara = (unsigned long *)regs->rsp - 1;
> >> +
> >> +	tsk = arch_get_kprobe_task(sara);
> >
> >I dont think you handle the case of the exception happening on
> >a exception or interrupt stack. This is broken.

What about this problem?