Re: [PATCH v4 13/17] khwasan: add hooks implementation
From: Christopher Lameter
Date: Tue Jul 31 2018 - 11:38:15 EST
On Tue, 31 Jul 2018, Dmitry Vyukov wrote:
> > Actually you should do this for SLAB_TYPESAFE_BY_RCU slabs. Usually they are with ->ctors but there
> > are few without constructors.
> > We can't reinitialize or even retag them. The latter will definitely cause false-positive use-after-free reports.
> Somewhat offtopic, but I can't understand how SLAB_TYPESAFE_BY_RCU
> slabs can be useful without ctors or at least memset(0). Objects in
> such slabs need to be type-stable, but I can't understand how it's
> possible to establish type stability without a ctor... Are these bugs?
> Or I am missing something subtle? What would be a canonical usage of
> SLAB_TYPESAFE_BY_RCU slab without a ctor?
True that sounds fishy. Would someone post a list of SLAB_TYPESAFE_BY_RCU
slabs without ctors?