Re: [PATCH v2 1/8] evtchn: avoid race in get_xen_consumer()

[Julien Grall <julien@xxxxxxx>]

Hi Jan,

On 20/10/2020 15:08, Jan Beulich wrote:
> There's no global lock around the updating of this global piece of data.
> Make use of cmpxchgptr() to avoid two entities racing with their
> updates.
>
> While touching the functionality, mark xen_consumers[] read-mostly (or
> else the if() condition could use the result of cmpxchgptr(), writing to
> the slot unconditionally).
>
> The use of cmpxchgptr() here points out (by way of clang warning about
> it) that its original use of const was slightly wrong. Adjust the
> placement, or else undefined behavior of const qualifying a function
> type will result.
>
> Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
Acked-by: Julien Grall <jgrall@xxxxxxxxxx>

Cheers,

--
Julien Grall