Re: [RFC] [Patch 1/1] [Self Ptrace] System call notification with self_ptrace

Oleg Nesterov
2008-08-25T16:49:32Z

On 08/25, Pierre Morel wrote:
>
> @@ -550,6 +550,23 @@ asmlinkage long sys_ptrace(long request,
> goto out;
> }
>
> + if (request == PTRACE_SELF_ON) {
> + task_lock(current);
> + set_thread_flag(TIF_SYSCALL_TRACE);
> + current->ptrace |= PT_SELF;

I didn't read the whole patch, but this sets PT_SELF without PT_PTRACED
(and without ptrace_attach).

We have some "->ptrace != 0" checks which can misunderstand this. Just
for example, suppose that the task does sys_ptrace(PTRACE_SELF_ON) and
then its parent dies. I guess in that case forget_original_parent()
will hit BUG_ON(p->ptrace), no?

Oleg.