Messages in this thread | | | Date | Fri, 5 Jun 2009 19:41:47 +0400 | From | Alexey Dobriyan <> | Subject | Re: [PATCH 1/9] exec_path 1/9: introduce ->exec_path and switch /proc/*/exe |
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On Fri, Jun 05, 2009 at 08:10:50AM -0700, Linus Torvalds wrote: > 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,
There is no mess in clone:
+ get_task_exec_path(current, &p->exec_path);
and there is no mess in exit:
+ set_task_exec_path(tsk, &(struct path){ .mnt = NULL, .dentry = NULL });
> > 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,
This mapping issue is what created VM_EXECUTABLE/MAP_EXECUTABLE in the first place, I assume? Never mind it's cheap hack.
> and goes along with task->mm, and should be there, not in task_struct.
Because ->mm can be borrowed to unrelated task and user has to check for it.
> So it should be copied at fork() time when you do the dup_mm(), not > anywhere else.
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