Index: head/sys/kern/kern_sig.c
===================================================================
--- head/sys/kern/kern_sig.c
+++ head/sys/kern/kern_sig.c
@@ -3094,12 +3094,17 @@
 void
 killproc(struct proc *p, char *why)
 {
+	int jid = -1;
 
+	if (p->p_ucred && p->p_ucred->cr_prison)
+		jid = p->p_ucred->cr_prison->pr_id;
+
 	PROC_LOCK_ASSERT(p, MA_OWNED);
 	CTR3(KTR_PROC, "killproc: proc %p (pid %d, %s)", p, p->p_pid,
 	    p->p_comm);
-	log(LOG_ERR, "pid %d (%s), uid %d, was killed: %s\n", p->p_pid,
-	    p->p_comm, p->p_ucred ? p->p_ucred->cr_uid : -1, why);
+	log(LOG_ERR, "pid %d (%s), jid %d, uid %d, was killed: %s\n",
+	    p->p_pid, p->p_comm, jid,
+	    p->p_ucred ? p->p_ucred->cr_uid : -1, why);
 	proc_wkilled(p);
 	kern_psignal(p, SIGKILL);
 }
@@ -3116,7 +3121,11 @@
 sigexit(struct thread *td, int sig)
 {
 	struct proc *p = td->td_proc;
+	int jid = -1;
 
+	if (p->p_ucred && p->p_ucred->cr_prison)
+		jid = p->p_ucred->cr_prison->pr_id;
+
 	PROC_LOCK_ASSERT(p, MA_OWNED);
 	p->p_acflag |= AXSIG;
 	/*
@@ -3142,8 +3151,8 @@
 			sig |= WCOREFLAG;
 		if (kern_logsigexit)
 			log(LOG_INFO,
-			    "pid %d (%s), uid %d: exited on signal %d%s\n",
-			    p->p_pid, p->p_comm,
+			    "pid %d (%s), jid %d, uid %d: exited on "
+			    "signal %d%s\n", p->p_pid, p->p_comm, jid,
 			    td->td_ucred ? td->td_ucred->cr_uid : -1,
 			    sig &~ WCOREFLAG,
 			    sig & WCOREFLAG ? " (core dumped)" : "");