lkml.org 
[lkml]   [2019]   [Feb]   [14]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [v5 PATCH 5/8] RISC-V: Compare cpuid with NR_CPUS before mapping.
From
Date
On 2/14/19 9:59 AM, Christopher Lameter wrote:
> On Wed, 13 Feb 2019, Atish Patra wrote:
>
>> --- a/arch/riscv/kernel/smpboot.c
>> +++ b/arch/riscv/kernel/smpboot.c
>> @@ -66,6 +66,11 @@ void __init setup_smp(void)
>> found_boot_cpu = 1;
>> continue;
>> }
>> + if (cpuid >= NR_CPUS) {
>
> Use nr_cpu_ids instead? Its initialized to NR_CPUS but can be restricted
> if we can determine on boot how many processor we truly have.
>
nr_cpu_ids can be modified by nr_cpus in boot command line. If nr_cpus
is set to a value less than number of cpus described in the DT, kernel
may not boot depending on the boot hartid. This happens because we break
out of the while loop and BUG_ON(!found_boot_cpu).

As the required fix will be different from the current fix, I would like
to do this in a follow up patch if that's ok.

Btw, thanks for bringing this up.

Regards,
Atish

\
 
 \ /
  Last update: 2019-02-15 00:34    [W:0.106 / U:0.056 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site