Re: [PATCH 1/1] Document get_user_pages_fast()

From: KOSAKI Motohiro
Date: Fri Apr 10 2009 - 00:14:22 EST


> > > and Cow change owner process.
> >
> > hm. buggy userspace? Why is that a problem from a kernel perspective?
>
> We already started to discuttion in "[PATCH] fork vs gup(-fast) fix" thread.
> but this is very difficult problem. it is still in progress ;)

note:
access_process_vm() tell us right get_user_pages() usage.
mmap_sem prevent fork in critical section. then it don't have cow risk.



> > > Yes, current all gup caller have serious bug. especially direct-io, aio, bio
> > > are broken.



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