Bluetooth: controller: assert on conn update in slave role under max. throughput usecases

[cvinayak]

[bt] [ERR] ticker_update_slave_assert: assert: '(status == 0) || (_radio.ticker_id_stop == ticker_id)' failed
***** Kernel OOPS! *****
Current thread ID = 0x20005d58
Faulting instruction address = 0x148a8
[general] [ERR] _SysFatalErrorHandler: Caught system error -- reason 4. Entering infinite loop 

This was reported under max. throughput usecases at 7.5ms conn intervals subjected to connection update procedures.

In slave role, ticker_update interface is used to compensate for clock drifts. ticker_stop and ticker_start interfaces are used to perform connection update. A race condition in the order of these calls is suspected to cause the assert.

A fix for this will be sent after a detailed analysis after a controlled reproduction of the said assert.

[nashif]

@cvinayak is this something that will be resolved for 1.13?

[cvinayak]

@nashif No, too close to the 1.13 release to reproduce, analyse and fix it, move it to 1.14.