On 23/09/2019 16:43, Dietmar Eggemann wrote: > I'm not sure that CONFIG_DEBUG_PER_CPU_MAPS=y will help you here. > > __set_cpus_allowed_ptr(...) > { > ... > dest_cpu = cpumask_any_and(...) > ... > } > > With: > > #define cpumask_any_and(mask1, mask2) cpumask_first_and((mask1), (mask2)) > #define cpumask_first_and(src1p, src2p) cpumask_next_and(-1, (src1p), > (src2p)) > > cpumask_next_and() is called with n = -1 and in this case does not > invoke cpumask_check(). >
It won't warn here because it's still a valid return value, but it should warn in the cpumask_test_cpu() that follows (in is_cpu_allowed()) because it would be passed a value >= nr_cpu_ids. So at the very least this config does catch cpumask_any*() return values being blindly passed to cpumask_test_cpu(). Calls to cpumask_any*() without relevant return value check can easily be spotted by the coccinelle snippet I sent earlier. If this one fix gets merged, I'll go and stare at / fixup the others (and maybe add the semantic patch to coccicheck). > --- > > BTW, I can recreate the issue quite easily with: > > qemu-system-x86_64 ... -smp cores=64 ... -enable-kvm > > with the default kernel config. > > Might want to send your tested-by to [1] then :) [1]: https://lkml.kernel.org/r/1568616808-16808-1-git-send-email-shikem...@huawei.com >