> > In filemap_map_pages()
> > CPU0 CPU1
> > trylock_page at offset_A trylock_page at offset_A
> > goto offset_A+1
> > if (!fe->pte) {
> > alloc pte
> > map pte
> > lock pte
> > }
> > handle offset_A with ptl held handle offset_A+1 without acquiring ptl
>
> I still don't see where's the problem.
>
> On the seond iteration (for offset_A+1), CPU1 would go into
> alloc_set_pte() and as its fe->pte is NULL pte_alloc_one_map() would map
> and lock the pte table allocated by CPU0.
>
Ah, you are right. I missed the 2nd fe!
thanks
Hillf
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