FindWriteTagByFlag(flush=false) is only called from
FormatMemWriteTagAtNoFlush(), which is itself only called from within
FlushPendingMemInfo() - which already holds pendingReadMutex for its
entire body. The previous commit added an unconditional lock of that
same (non-recursive) mutex here, so any path that reaches a memory
write's tag formatting while a flush is in progress double-locks it
and hangs/crashes.
Repro: PPSSPPHeadless --graphics=software on
pspautotests/tests/gpu/clipping/homogeneous.prx reliably hit this.
Only take the lock when flush=true (i.e. when we're not already
guaranteed to be called from inside FlushPendingMemInfo's locked
section), using a defer_lock so the two call sites stay consistent.
Verified fixed: 4/4 clean runs of the repro above, plus the full
UnitTest suite (49/49) still passes.
Henrik Rydgård
9afab39bc8