[Skiboot] [PATCH] ipmi: ensure forward progress on ipmi_queue_msg_sync()

Vasant Hegde hegdevasant at linux.vnet.ibm.com
Tue May 7 15:45:11 AEST 2019


On 05/01/2019 12:35 PM, Stewart Smith wrote:
> BT responses are handled using a timer doing the polling. To hope to
> get an answer to an IPMI synchronous message, the timer needs to run.
> 
> We can't just check all timers though as there may be a timer that
> wants a lock that's held by a code path calling ipmi_queue_msg_sync(),
> and if we did enforce that as a requirement, it's a pretty subtle
> API that is asking to be broken.
> 
> So, if we just run a poll function to crank anything that the IPMI
> backend needs, then we should be fine.
> 
> This issue shows up very quickly under QEMU when loading the first
> flash resource with the IPMI HIOMAP backend.
> 
> Reported-by: Cédric Le Goater <clg at kaod.org>
> Signed-off-by: Stewart Smith <stewart at linux.ibm.com>

Reviewed-by: Vasant Hegde <hegdevasant at linux.vnet.ibm.com>

-Vasant



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