Re: [PATCH v2 0/2] Couple of SCMI race fixes

[Sudeep Holla]

On Wed, 09 Sep 2026 04:32:26 +0000, Roland Dreier wrote:
> Noticed a couple of races in SCMI code around delayed responses that
> time out. These are probably nearly impossible to hit in practice but
> the fixes are pretty straightforward and it seems worth having the
> code be sound.
> 
> The v1 fixes were correct as posted, despite Sashiko warning that the
> new "delayed_response_dropped" debug counter might never increment.
> However, that review made me think that a new debug counter for a
> one-in-a-gazillion race condition is probably less useful than a
> kernel error message. So the change in v2 is having the first patch
> log an error for a delayed response that arrives in the race window it
> closes (matching the existing "Delayed Response not expected" error in
> scmi_msg_response_validate()). The new error is expected to be
> extremely rare but it makes sure there is no path where a delayed
> response gets matched and then discarded without any logging.
> 
> [...]

Applied to sudeep.holla/linux (for-next/scmi/updates), thanks!

[1/2] firmware: arm_scmi: Protect xfer->async_done with xfer->lock
      https://git.kernel.org/sudeep.holla/c/49fc5bc04eec
[2/2] firmware: arm_scmi: Don't reuse raw xfers with async_done still armed
      https://git.kernel.org/sudeep.holla/c/0543fc1443de
-- 
Regards,
Sudeep