On 03/24, Mateusz Guzik wrote: > > I had cursory glances at this code earlier and the more I try to > understand it the more confused I am. You are not alone ;) > Per my other e-mail the obvious scheme would serialize all execs > sharing ->fs and make copy_fs do a killable wait for execs to finish. > Arguably this would also improve userspace-visible behavior as a > transient -EBUSY would be eliminated. I had the same feeling years ago. Why didn't I do it? I can't recall. Perhaps because I found some problem in this idea, but most probably because I failed to make the correct and simple patch. > is there a problem getting this done even for stable kernels? I > understand it would be harder to backport churn-wise, but should be > much easier to reason about? I won't argue with another solution. But this problem is quite old, unless I am totally confused this logic was wrong from the very beginning when fs->in_exec was introduced by 498052bba55ec. So to me it would be better to have the trivial fix for stable, exactly because it is trivially backportable. Then cleanup/simplify this logic on top of it. Oleg.
