Re: futex question

From: Ingo Molnar
Date: Mon Oct 05 2009 - 07:21:12 EST



* Peter Zijlstra <a.p.zijlstra@xxxxxxxxx> wrote:

> diff --git a/fs/exec.c b/fs/exec.c
> index d49be6b..0812ba6 100644
> --- a/fs/exec.c
> +++ b/fs/exec.c
> @@ -1295,6 +1295,22 @@ int do_execve(char * filename,
> bool clear_in_exec;
> int retval;
>
> + retval = -EWOULDBLOCK;
> +#ifdef CONFIG_FUTEX
> + if (unlikely(current->robust_list))
> + goto out_ret;
> +#ifdef CONFIG_COMPAT
> + if (unlikely(current->compat_robust_list))
> + goto out_ret;
> +#endif
> + spin_lock_irq(&current->pi_lock);
> + if (!list_empty(&current->pi_state_list)) {
> + spin_unlock_irq(&current->pi_lock);
> + goto out_ret;
> + }
> + spin_unlock_irq(&current->pi_lock);
> +#endif

i suspect this should have the form of:

retval = can_exec_robust_futexes();
if (retval)
goto out_ret

retval = unshare_files(&displaced);
if (retval)
goto out_ret;

...

but ... shouldnt we just do what exec normally does and zap any state
that shouldnt be carried over into the new context - instead of denying
the exec? Am i missing something?

Ingo
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