On Thu, Jan 25, 2024 at 11:15:44AM +0000, Sudeep Holla wrote: > On Tue, Dec 12, 2023 at 02:25:16PM -0800, Ricardo Neri wrote: > > Before determining the validity of the last-level cache info, ensure that > > it has been allocated. Simply checking for non-zero cache_leaves() is not > > sufficient, as some architectures (e.g., Intel processors) have non-zero > > cache_leaves() before allocation. > > > > Dereferencing NULL cacheinfo can occur in update_per_cpu_data_slice_size(). > > This function iterates over all online CPUs. However, a CPU may have come > > online recently, but its cacheinfo may not have been allocated yet. > > > > Cc: Andreas Herrmann <aherrmann@xxxxxxxx> > > Cc: Catalin Marinas <catalin.marinas@xxxxxxx> > > Cc: Chen Yu <yu.c.chen@xxxxxxxxx> > > Cc: Huang Ying <ying.huang@xxxxxxxxx> > > Cc: Len Brown <len.brown@xxxxxxxxx> > > Cc: Radu Rendec <rrendec@xxxxxxxxxx> > > Cc: Pierre Gondois <Pierre.Gondois@xxxxxxx> > > Cc: Pu Wen <puwen@xxxxxxxx> > > Cc: "Rafael J. Wysocki" <rafael.j.wysocki@xxxxxxxxx> > > Cc: Sudeep Holla <sudeep.holla@xxxxxxx> > > If you respin, you can address the below minor nit. I am fine as is as > well. > > Reviewed-by: Sudeep Holla <sudeep.holla@xxxxxxx> Thank you for your review Sudeep! > > [...] > > > diff --git a/drivers/base/cacheinfo.c b/drivers/base/cacheinfo.c > > index f1e79263fe61..967c5cf3fb1d 100644 > > --- a/drivers/base/cacheinfo.c > > +++ b/drivers/base/cacheinfo.c > > @@ -61,6 +61,9 @@ bool last_level_cache_is_valid(unsigned int cpu) > > if (!cache_leaves(cpu)) > > return false; > > > > + if (!per_cpu_cacheinfo(cpu)) > > + return false; > > + > > [nit] You can even combine this with above if condition. Sure, I can take care of this if a new version is needed as per feedback from the x86 maintainers.
