On Fri, Mar 08, 2024 at 09:08:59AM -0800, Christoph Lameter (Ampere) wrote: > On Fri, 8 Mar 2024, Marek Szyprowski wrote: > > > > > > > > > It looks that cpufreq-dt and/or opp drivers needs some adjustments > > > > related with this change. > > > That's strange. Is this with defconfig? I wonder whether NR_CPUS being > > > larger caused the issue with this specific code. Otherwise > > > CPUMASK_OFFSTACK may not work that well on arm64. > > cpumask handling must use the accessor functions provided in > include/linux/cpumask.h for declaring and accessing cpumasks. It is likely > related to the driver opencoding one of the accessors. I took a look at both the OPP code and the cpufreq-dt code and it looks like those are doign the right thing w.r.t. cpumask manipulation (i.e. they only use the cpumask accessors, and use the cpumask_var_*() functions to dynamically allocate/free cpumasks). Maybe I've missed something, but superficially those look right. Marek, can you try reverting this commit and trying defconfig + NR_CPUS=512? That'll have CPUMASK_OFFSTACK=n, and: * If that blows up, we know the problem is independent of CPUMASK_OFFSTACK, and has something to do with large cpumasks (either a driver bug, or elsewhere). * If that doesn't blow up, it suggests the problem is related to CPUMASK_OFFSTACK rather than with large cpumasks specifically. Either way, we probably need to revert this patch for now, as this won't have enough time to soak in linux-next in time for v6.9. Mark.
