Subj. It's integer so assignments are atomic.
Index: sys/sys/proc.h
===================================================================
RCS file: /cvs/src/sys/sys/proc.h,v
retrieving revision 1.304
diff -u -p -r1.304 proc.h
--- sys/sys/proc.h 11 Jan 2021 13:55:53 -0000 1.304
+++ sys/sys/proc.h 13 Jan 2021 19:17:51 -0000
@@ -216,7 +216,7 @@ struct process {
u_int ps_xexit; /* Exit status for wait */
int ps_xsig; /* Stopping or killing signal */
- pid_t ps_oppid; /* Save parent pid during ptrace. */
+ pid_t ps_oppid; /* [a] Save parent pid during ptrace. */
int ps_ptmask; /* Ptrace event mask */
struct ptrace_state *ps_ptstat;/* Ptrace state */
