Re: [uml-devel] NPTL pthread_create() cannot work.

[Blaisorblade <blaisorblade@yahoo.it>]

On Friday 29 July 2005 13:12, Zhu Tom-a2289c wrote:
> Dear all,

> I am using patch 
> <http://www.user-mode-linux.org/~blaisorblade/patches/devel-guest/uml-2.6.1
>2-rc4-bb-20050521-18:54/uml-2.6.12-rc4-bb-20050521-18:54.patch.bz2>
> uml-2.6.12-rc4-bb-20050521-18:54.patch.bz2 on kernel 2.6.12-rc4. but found
> pthread_create() cannot work.

> it seems, in copy_thread() in arch/um/kernel/process_kern.c, the ret
> value's setting is not correct
Yes, I already fixed that recently - that patch is a development one and 
you're the first tester I heard of.

> int copy_thread(int nr, unsigned long clone_flags, unsigned long sp,
>   unsigned long stack_top, struct task_struct * p,
>   struct pt_regs *regs)
> {
>  int ret;
>
>  p->thread = (struct thread_struct) INIT_THREAD;
>  ret = CHOOSE_MODE_PROC(copy_thread_tt, copy_thread_skas, nr,
>     clone_flags, sp, stack_top, p, regs);
>
>  if (ret || !current->thread.forking)
>   goto out;
>
>  clear_flushed_tls(p);
>
>  if (UPT_ESI(&current->thread.regs.regs) != UPT_ESI(&p->thread.regs.regs))
>   printk(KERN_DEBUG "newtls_new %x,old %x\n", (unsigned int)
> UPT_ESI(&current->thread.regs.regs), (unsigned int)
> UPT_ESI(&p->thread.regs.regs));
>
>  /*
>   * Set a new TLS for the child thread?
>   */
>  if (clone_flags & CLONE_SETTLS) {
>   struct user_desc info;
>   int idx;
>
>   ret = -EFAULT;
>   if (copy_from_user(&info, (void __user
> *)UPT_ESI(&current->thread.regs.regs), sizeof(info))) goto out;
>   ret = -EINVAL;
>   if (LDT_empty(&info))
>    goto out;
>
>   idx = info.entry_number;
>
>   set_tls_entry(p, &info, idx, 0);
>  }
>
> out:
>  return ret;
> }
>
>
> I add a "ret=0;" after set_tls_entry(p, &info, idx, 0);

> after it, pthread_create() can return correctly, but the new thread cannot
> be scheduled correctly. there is always a "Segment Fault".
I've succeeded in fixing even this...
> I am using libc 2.3.3 and libc 2.3.4.
>
> Note:
> on 2.3.2, no "Segment Fault", it looks good.
Is that compiled with NPTL / TLS support? Has 2.3.2 any TLS support at all?
> Has anyone had a test of NPTL on UML?
Currently it is known not to work, but I'm working on fixing that.
-- 
Inform me of my mistakes, so I can keep imitating Homer Simpson's "Doh!".
Paolo Giarrusso, aka Blaisorblade (Skype ID "PaoloGiarrusso", ICQ 215621894)
http://www.user-mode-linux.org/~blaisorblade


		
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