[parent] before attach: child ppid=945
[parent] wrote 'attach' (6 bytes) to /proc/947/ctl
[parent] wrote 'detach' (6 bytes) to /proc/947/ctl
[parent] after detach:  child ppid=0
RESULT: BUG REPRODUCED -- child orphaned to proc0 (ppid=0) after procfs attach/detach
waitpid(947)=-1 errno=10 (ECHILD)
---- /proc/947/status ----
df0911 947 0 944 944 -1,-1 noflags 1783826057,812697 0,0 0,0 nanslp 1001 1001 1001,1001 -
BASELINE_EXIT=0

Kernel: DragonFly 6.5-DEVELOPMENT #0: Thu Jul  2 06:02:54 UTC 2026 (unpatched audit-source)

Three additional runs all produced the same marker:
RESULT: BUG REPRODUCED -- child orphaned to proc0 (ppid=0) after procfs attach/detach