Re: [PATCH bpf 1/2] uprobes/x86: Fix red zone clobbering in nop5 optimization

[Oleg Nesterov]

On 05/08, Andrii Nakryiko wrote:
>
> +static bool resolve_uprobe_addr(unsigned long ip, unsigned long *probe_addr)
>  {
> -     struct vm_area_struct *vma = vma_lookup(current->mm, ip);
> +     struct uprobes_state *state = &current->mm->uprobes_state;

it seems that there is a problem, with or without this change...

Lets forget about this patch for the moment, I am still trying to understand it.

What if register_for_each_vma() calls install_breakpoint(vma) and
vma->mm != current->mm ?

In this case install_breakpoint() path will call __is_optimized() and then
__in_uprobe_trampoline() which does vma_lookup(current->mm). This looks
obviously wrong ?

And unless I am totally confused, this patch "inherits" the problem...

No?

Oleg.