tree 7bea0c9b17cd04f659e8455284e46c9d0bf9be7d
parent d8b41fc677ad4a83a414d17215da2cd767cc47ad
author Neels Hofmeyr <neels@hofmeyr.de> 1535399689 +0200
committer Neels Hofmeyr <neels@hofmeyr.de> 1535500930 +0200

lchan_fsm: lchan_fail_to(): store target state early

lchan_fail_to() is a macro to preserve useful source file:line information in
logging. But a side effect is that its target state argument might evaluate
differently at the end of the macro, if, say, the fi->state has changed.

I hit such an instance on timeout of WAIT_RLL_RTP_ESTABLISH:
lchan_fsm_timer_cb() calls macro lchan_fail(), which calls
lchan_fail_to(lchan_fsm_on_error[fi->state]). Unlike for normal function
invocation, this argument changes as fi->state changes. Since releasing the
lchan_rtp_fsm already transitions the lchan fi into WAIT_RF_RELEASE_ACK, the
final state change of lchan_fail_to() suddenly evaluates to the broken state
instead of the intended WAIT_RF_RELEASE_ACK.

Early in lchan_fail_to(), store the argument's value as of macro invocation.

Change-Id: Id9bf4580a112ee5629f553a8bcb6b5b03b1c5f53