Re: [PATCH v2 2/2] x86/mce: Avoid arming periodic polling timer when not required

[Aaron Tomlin]

On Wed, Sep 02, 2026 at 10:15:27AM -0700, Luck, Tony wrote:
> Hi Aaron,
> 
> You have one small bug. Your check whether mce_poll_banks is empty looks
> at all MAX_NR_BANKS (64). But all Intel systems implement fewer banks,
> and only clear the bits for banks that exist, leaving some upper bits
> set in the bitmask.
> 
> This means the timer keeps running.
> 
> Please send a v3 with the updates to the commit message listed above,
> and with the change below folded into your change.
> 
> Thanks
> 
> -Tony

Hi Tony,

Indeed, since mce_poll_banks is initialised to ~0UL across all
MAX_NR_BANKS, the unimplemented upper bits above mce_num_banks remained
set, preventing bitmap_empty() from ever returning true.

    DEFINE_PER_CPU(mce_banks_t, mce_poll_banks) = {
        [0 ... BITS_TO_LONGS(MAX_NR_BANKS)-1] = ~0UL
    };

I will send out the v3 series shortly. Thank you.

Kind regards,
-- 
Aaron Tomlin