On 26.02.2020 13:38, Roger Pau Monne wrote:
> Using scratch_cpumask in send_IPI_mask is not safe in IRQ or exception
> context because it can nest, and hence send_IPI_mask could be
> overwriting another user scratch cpumask data when used in such
> contexts.
>
> Instead introduce a new cpumask to be used by send_IPI_mask, and
> disable interrupts while using it.
With this now apparently stale sentence dropped (easily done
while committing)
> Fallback to not using the scratch cpumask (and hence not attemping to
> optimize IPI sending by using a shorthand) when in IRQ or exception
> context. Note that the scratch cpumask cannot be used when
> non-maskable interrupts are being serviced (NMI or #MC) and hence
> fallback to not using the shorthand in that case, like it was done
> previously.
>
> Fixes: 5500d265a2a8 ('x86/smp: use APIC ALLBUT destination shorthand when
> possible')
> Reported-by: Sander Eikelenboom <li...@eikelenboom.it>
> Signed-off-by: Roger Pau Monné <roger....@citrix.com>
Reviewed-by: Jan Beulich <jbeul...@suse.com>
Jan
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