Index: sys/amd64/amd64/exec_machdep.c
===================================================================
--- sys/amd64/amd64/exec_machdep.c
+++ sys/amd64/amd64/exec_machdep.c
@@ -196,8 +196,10 @@
 	    (xfpusave != NULL && copyout(xfpusave,
 	    (void *)sf.sf_uc.uc_mcontext.mc_xfpustate, xfpusave_len)
 	    != 0)) {
+#ifdef DEBUG
 		uprintf("pid %d comm %s has trashed its stack, killing\n",
 		    p->p_pid, p->p_comm);
+#endif
 		PROC_LOCK(p);
 		sigexit(td, SIGILL);
 	}
@@ -245,14 +247,18 @@
 
 	error = copyin(uap->sigcntxp, &uc, sizeof(uc));
 	if (error != 0) {
+#ifdef DEBUG
 		uprintf("pid %d (%s): sigreturn copyin failed\n",
 		    p->p_pid, td->td_name);
+#endif
 		return (error);
 	}
 	ucp = &uc;
 	if ((ucp->uc_mcontext.mc_flags & ~_MC_FLAG_MASK) != 0) {
+#ifdef DEBUG
 		uprintf("pid %d (%s): sigreturn mc_flags %x\n", p->p_pid,
 		    td->td_name, ucp->uc_mcontext.mc_flags);
+#endif
 		return (EINVAL);
 	}
 	regs = td->td_frame;
@@ -261,8 +267,10 @@
 	 * Don't allow users to change privileged or reserved flags.
 	 */
 	if (!EFL_SECURE(rflags, regs->tf_rflags)) {
+#ifdef DEBUG
 		uprintf("pid %d (%s): sigreturn rflags = 0x%lx\n", p->p_pid,
 		    td->td_name, rflags);
+#endif
 		return (EINVAL);
 	}
 
@@ -273,8 +281,10 @@
 	 */
 	cs = ucp->uc_mcontext.mc_cs;
 	if (!CS_SECURE(cs)) {
+#ifdef DEBUG
 		uprintf("pid %d (%s): sigreturn cs = 0x%x\n", p->p_pid,
 		    td->td_name, cs);
+#endif
 		ksiginfo_init_trap(&ksi);
 		ksi.ksi_signo = SIGBUS;
 		ksi.ksi_code = BUS_OBJERR;
@@ -288,8 +298,10 @@
 		xfpustate_len = uc.uc_mcontext.mc_xfpustate_len;
 		if (xfpustate_len > cpu_max_ext_state_size -
 		    sizeof(struct savefpu)) {
+#ifdef DEBUG
 			uprintf("pid %d (%s): sigreturn xfpusave_len = 0x%zx\n",
 			    p->p_pid, td->td_name, xfpustate_len);
+#endif
 			return (EINVAL);
 		}
 		xfpustate = (char *)fpu_save_area_alloc();
@@ -297,9 +309,11 @@
 		    xfpustate, xfpustate_len);
 		if (error != 0) {
 			fpu_save_area_free((struct savefpu *)xfpustate);
+#ifdef DEBUG
 			uprintf(
 	"pid %d (%s): sigreturn copying xfpustate failed\n",
 			    p->p_pid, td->td_name);
+#endif
 			return (error);
 		}
 	} else {
@@ -309,8 +323,10 @@
 	ret = set_fpcontext(td, &ucp->uc_mcontext, xfpustate, xfpustate_len);
 	fpu_save_area_free((struct savefpu *)xfpustate);
 	if (ret != 0) {
+#ifdef DEBUG
 		uprintf("pid %d (%s): sigreturn set_fpcontext err %d\n",
 		    p->p_pid, td->td_name, ret);
+#endif
 		return (ret);
 	}
 	bcopy(&ucp->uc_mcontext.mc_rdi, regs, sizeof(*regs));
Index: sys/amd64/linux/linux_sysvec.c
===================================================================
--- sys/amd64/linux/linux_sysvec.c
+++ sys/amd64/linux/linux_sysvec.c
@@ -556,8 +556,10 @@
 	 * one less debugger trap, so allowing it is fairly harmless.
 	 */
 	if (!EFL_SECURE(rflags & ~PSL_RF, regs->tf_rflags & ~PSL_RF)) {
+#ifdef DEBUG
 		uprintf("pid %d comm %s linux mangled rflags %#lx\n",
 		    p->p_pid, p->p_comm, rflags);
+#endif
 		return (EINVAL);
 	}
 
@@ -567,8 +569,10 @@
 	 * other selectors, invalid %eip's and invalid %esp's.
 	 */
 	if (!CS_SECURE(context->sc_cs)) {
+#ifdef DEBUG
 		uprintf("pid %d comm %s linux mangled cs %#x\n",
 		    p->p_pid, p->p_comm, context->sc_cs);
+#endif
 		ksiginfo_init_trap(&ksi);
 		ksi.ksi_signo = SIGBUS;
 		ksi.ksi_code = BUS_OBJERR;