tree a2eeebb44956d0a12fd5a3e2b51c8e0076d4c5b8
parent dd7ebf179f351a403027d1b216049d1a5b88e2cd
author Andrzej Kaczmarek <andrzej.kaczmarek@codecoup.pl> 1618317389 +0200
committer Andrzej Kaczmarek <andrzej.kaczmarek@codecoup.pl> 1618386428 +0200

transport/cmac: Fix race on LL event write

HCI commands are processed in LL task context and thus CS/CC events are
written to mbox in the same context. This can lead to following race:
- CS/CC is written to mbox
- interrupt in handled on CMAC *before* command buffer is freed
- M33 reads CS/CC and writes next command to mbox
- CMAC reads new command

This triggers an assert in code because we do not have free buffer for
new command because we were busy handling interrupts and did not free
it yet.

To fix this we should write and free in critical section.