23 wait frames, 30 objects, nothing unresolved -- the second deref turns every
former miss into a resolved object, as predicted. XEvent 20 / XSemaphore 9 /
XTimer 1; every WaitMultiple thread waits on a pair, and 78/79/80 and 64/65 are
worker groups sharing a handle.
%ebp does not survive as the count -- WaitMultiple reuses it at 8fc158 -- so the
array is bounded by reading until an entry stops resolving instead.
The frozen capture is still not taken: screen_id reads 'flight' at the second
capture and out to ~470s, so the mission never black-screened. The diff in the
data file is two healthy captures and is recorded as such.
The 8 threads whose [rbx] did not resolve to a vtable were never in
XObject::Wait. The backtrace grep matched WaitMultiple as a substring, and
there %rbx is the XObject** array (mov %rsi,%rbx) with the count in %ebp, so
[rbx] is objects[0] -- an object pointer, needing a second deref -- not a
vtable. The unwind restored rbx correctly for all 18.
freeze_waitobj.sh now takes the function and frame index from the backtrace and
applies the matching read, and captures twice in one run (healthy and after the
~270s black-screen) so the comparison is within-run. waitobj_report.py tabulates
both and diffs them, discarding any value info symbol cannot resolve.
