Bug (High Severity): Wrong queue type in MemDiscardCallstack
In the callstack path of MemDiscardCallstack, the wrong queue type is
sent:
SendMemDiscard( QueueType::MemDiscard, thread, name );
Every other callstack variant correctly uses its callstack queue type
(MemAllocCallstack, MemFreeCallstack, etc.), but this one uses the
non-callstack type. The SendMemDiscard assertion at line 1026 confirms
MemDiscardCallstack is a valid value.
Impact: The callstack captured by SendCallstackSerial() will be orphaned.
The server processes the event via the non-callstack handler, leaving the
callstack serial data unconsumed, which desynchronizes the serial queue
and corrupts all subsequent events.
A zone emitted from a shared object initializer runs before the
executable's constructors, so its timestamp precedes s_initTime, which
the server uses as the trace epoch (baseTime). Such a zone converts to
negative trace time and its end no longer satisfies IsEndValid(), which
excludes it from statistics reconstruction and makes it render as
never-ending.
Record the current time when a producer token is created before
s_initTime is constructed and use it as the init time, ensuring no event
timestamp precedes the trace epoch.
ELF init_priority only orders constructors within a single module. All of
a shared object's initializers run before any of the executable's, so an
instrumented dependency .so emitting a zone from its static initializer
creates the main thread producer token against the zero-initialized
s_queue. The queue constructor then resets the producer list, orphaning
that producer: every zone emitted on the main thread from that point on
is enqueued into blocks no consumer ever iterates and silently lost,
while sampling (worker thread producer) keeps working.
Re-link such a producer right after the queue is constructed. In the
common case, where nothing was emitted during shared object init, this
merely constructs the main thread token eagerly.
