Re: [BUG][PATCH] 2.4.* mlockall(MCL_FUTURE) is broken -- child inherits VM_LOCKED

[Andrew Morton <akpm@zip.com.au>]

Bruce Blinn wrote:
> 
> Andrew Morton wrote:
> >
> > Dave Anderson wrote:
> > >
> > > In 2.4.*, mlockall(MCL_FUTURE) is erroneously inherited by child processes
> > > across fork() and exec():
> >
> > The Linux manpage says that it is not inherited across either.
> >
> > However SUS says that it is not inherited across exec, and
> > doesn't mention fork() at all.
> > http://www.opengroup.org/onlinepubs/007908799/xsh/mlockall.html
> >
> > So...  Shouldn't we be clearing it in the exec() path?
> >
> 
> But, the SUS documentation for fork() says that it does not inherit the
> memory locks of the parent.  It explicitly mentions mlockall().
> 
>         http://www.opengroup.org/onlinepubs/007908799/xsh/fork.html

So it does.  So clearing it on fork is correct.  And my comment
regarding def_flags was nonsense.  Probably it's best to explicitly
clear VM_LOCKED, just in case something else gets added to def_flags
in the future.

Apart from that - ship it :)

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