Re: INFO: possible recursive locking detected: get_partial_node()on 3.2-rc1

[Christoph Lameter]

On Fri, 11 Nov 2011, Shaohua Li wrote:

> Looks this could be a real dead lock. we hold a lock to free a object,
> but the free need allocate a new object. if the new object and the freed
> object are from the same slab, there is a deadlock.

unfreeze partials is never called when going through get_partial_node()
so there is no deadlock AFAICT.

> discard_slab() doesn't need hold the lock if the slab is already removed
> from partial list. how about below patch, only compile tested.

In general I think it is good to move the call to discard_slab() out from
under the list_lock in unfreeze_partials(). Could you fold
discard_page_list into unfreeze_partials()? __flush_cpu_slab still calls
discard_page_list with disabled interrupts even after your patch.



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