Per thread cached credentials are accessed only by curproc. Curproc
doesn't modify it's 'p_ucred' directly. It allocates new copy, then
modyfies newcopy and replaces the old. So 'p_ucred' is owned by curproc.
Index: sys/sys/proc.h
===================================================================
RCS file: /cvs/src/sys/sys/proc.h,v
retrieving revision 1.294
diff -u -p -r1.294 proc.h
--- sys/sys/proc.h 6 Apr 2020 07:52:12 -0000 1.294
+++ sys/sys/proc.h 24 Apr 2020 10:12:56 -0000
@@ -392,7 +392,7 @@ struct proc {
u_int p_estcpu; /* [s] Time averaged val of p_cpticks */
int p_pledge_syscall; /* Cache of current syscall */
- struct ucred *p_ucred; /* cached credentials */
+ struct ucred *p_ucred; /* [o] cached credentials */
struct sigaltstack p_sigstk; /* sp & on stack state variable */
u_long p_prof_addr; /* tmp storage for profiling addr until AST */
