> > This is not only about chasing a bug. This also about preventing > > memory corruption and information leaking that are caused by ref_count > > bugs from happening. > > So you mean it like a security hardening feature, not just debugging? To me > it's dubious to put security hardening under CONFIG_DEBUG_VM. I think it's > just Fedora that uses DEBUG_VM in general production kernels? In our (Google) internal kernel, I added another macro: PAGE_REF_BUG(cond, page) to replace VM_BUG_ON_PAGE() in page_ref.h. The new macro keeps the asserts always enabled. I was thinking of adding something like this to the upstream kernel as well, however, I am worried about performance implications of having extra conditions in these routines, so I think we would need yet another config which decouples DEBUG_VM and some security crucial VM asserts. However, to reduce controversial discussions, I decided not to do this as part of this series, and perhaps do it as a follow-up work. Pasha
