Messages in this thread | | | Date | Wed, 19 Dec 2012 19:01:30 -0800 | Subject | Re: [PATCH] mm: protect against concurrent vma expansion | From | Michel Lespinasse <> |
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Hi Simon,
On Wed, Dec 19, 2012 at 5:56 PM, Simon Jeons <simon.jeons@gmail.com> wrote: > One question. > > I found that mainly callsite of expand_stack() is #PF, but it holds > mmap_sem each time before call expand_stack(), how can hold a *shared* > mmap_sem happen?
the #PF handler calls down_read(&mm->mmap_sem) before calling expand_stack.
I think I'm just confusing you with my terminology; shared lock == read lock == several readers might hold it at once (I'd say they share it)
-- Michel "Walken" Lespinasse A program is never fully debugged until the last user dies.
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