Re: [PATCH] Fix isocpus's param handling when CPUMASK_OFFSTACK=n.

[Ingo Molnar <mingo@kernel.org>]

* Rakib Mullick <rakib.mullick@gmail.com> wrote:

>  cpulist_parse() uses nr_cpumask_bits as limit to parse the
> passed buffer from kernel commandline. What nr_cpumask_bits
> represents varies depends upon CONFIG_CPUMASK_OFFSTACK option.
> If CONFIG_CPUMASK_OFFSTACK=n, then nr_cpumask_bits is same as
> NR_CPUS, which might not represent the # of cpus really exist
> (default 64). So, there's a chance of gap between nr_cpu_ids
> and NR_CPUS, which ultimately lead towards invalid cpulist_parse()
> operation. For example, if isolcpus=9 is passed on a 8 cpu
> system (CONFIG_CPUMASK_OFFSTACK=n) it doesn't show the error
> that it suppose to.
> 
> This patch fixes this issue by effectively find out the last
> cpu of the passed isolcpus list and checking it with nr_cpu_ids.
> Also, fixes the error message where the nr_cpu_ids should be
> nr_cpu_ids-1, since the cpu numbering starts from 0.
> 
> Signed-off-by: Rakib Mullick <rakib.mullick@gmail.com>
> ---
>  include/linux/cpumask.h | 16 ++++++++++++++++
>  kernel/sched/topology.c |  8 +++++---
>  2 files changed, 21 insertions(+), 3 deletions(-)

What kernel is this against? It does not apply to the latest kernels.

Thanks,

	Ingo