Re: lockdep question (was Re: IPoIB caused a kernel: BUG: softlockup detected on CPU#0!)

[Ingo Molnar]

* Michael S. Tsirkin <mst@xxxxxxxxxxxxxx> wrote:

> > So either there are other sites that instanciate those objects and
> > forget about the lock init, or the object is corrupted (use after free?)
> 
> OK, thanks for the hint. So I added this:

> And sure enough it triggers:
> 
> [  858.503010] ipoib_neigh_destructor lock c0687880 wrong type 772 !!!!!!!!!!

could you turn on CONFIG_SLAB_DEBUG as well?

that should catch certain types of use-after-free accesses, and lockdep 
will also warn if a still locked object is freed.

	Ingo
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