Re: [PATCH 1/9] exec_path 1/9: introduce ->exec_path and switch/proc/*/exe

From: Linus Torvalds
Date: Fri Jun 05 2009 - 11:11:30 EST




On Fri, 5 Jun 2009, Christoph Hellwig wrote:
>
> On Thu, Jun 04, 2009 at 03:04:22AM +0400, Alexey Dobriyan wrote:
> > ->exec_path is copied on clone(2) and put at do_exit() time.
> >
> > ->exec_path is going to replace struct mm_struct::exe_file et al
> > and allows to remove VM_EXECUTABLE flag while keeping readlink("/proc/*/exe")
> > without loop over all VMAs.
>
> Why don't you leave it in mm_struct? That'll avoid having to mess with
> it in clone, and given that exec always replaces the whole VM it's a
> more natural fit anyway.

Oh, I didn't even notice that, because I just assumed it was in mm_struct
already due to the earlier discussion.

So I concur with Christoph - that field should be in the mm_struct. The
executable is a "mapping" issue, and goes along with task->mm, and should
be there, not in task_struct.

So it should be copied at fork() time when you do the dup_mm(), not
anywhere else.

Linus
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