On 11.03.2024 13:12, Mark Rutland wrote: > 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? Yes, with $subject reverted and CONFIG_NR_CPUS=512 everything works fine, so it must be something else broken. > 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. Best regards -- Marek Szyprowski, PhD Samsung R&D Institute Poland
