diff --git a/sys/amd64/amd64/machdep.c b/sys/amd64/amd64/machdep.c
index df831a1968d..2e035798c80 100644
--- a/sys/amd64/amd64/machdep.c
+++ b/sys/amd64/amd64/machdep.c
@@ -357,7 +357,7 @@ sendsig(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask)
 
 	regs->tf_rsp = (long)sfp;
 	regs->tf_rip = PS_STRINGS - *(p->p_sysent->sv_szsigcode);
-	regs->tf_rflags &= ~PSL_T;
+	regs->tf_rflags &= ~(PSL_T | PSL_D);
 	regs->tf_cs = _ucodesel;
 	PROC_LOCK(p);
 	mtx_lock(&psp->ps_mtx);
diff --git a/sys/amd64/ia32/ia32_signal.c b/sys/amd64/ia32/ia32_signal.c
index 1d693b4c47e..a6d82a447cd 100644
--- a/sys/amd64/ia32/ia32_signal.c
+++ b/sys/amd64/ia32/ia32_signal.c
@@ -391,7 +391,7 @@ freebsd4_ia32_sendsig(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask)
 
 	regs->tf_rsp = (uintptr_t)sfp;
 	regs->tf_rip = FREEBSD32_PS_STRINGS - sz_freebsd4_ia32_sigcode;
-	regs->tf_rflags &= ~PSL_T;
+	regs->tf_rflags &= ~(PSL_T | PSL_D);
 	regs->tf_cs = _ucode32sel;
 	regs->tf_ss = _udatasel;
 	load_ds(_udatasel);
@@ -511,7 +511,7 @@ ia32_sendsig(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask)
 
 	regs->tf_rsp = (uintptr_t)sfp;
 	regs->tf_rip = FREEBSD32_PS_STRINGS - *(p->p_sysent->sv_szsigcode);
-	regs->tf_rflags &= ~PSL_T;
+	regs->tf_rflags &= ~(PSL_T | PSL_D);
 	regs->tf_cs = _ucode32sel;
 	regs->tf_ss = _udatasel;
 	load_ds(_udatasel);
diff --git a/sys/amd64/linux32/linux32_sysvec.c b/sys/amd64/linux32/linux32_sysvec.c
index 39068525ebf..9259092928f 100644
--- a/sys/amd64/linux32/linux32_sysvec.c
+++ b/sys/amd64/linux32/linux32_sysvec.c
@@ -401,7 +401,7 @@ linux_rt_sendsig(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask)
 	regs->tf_rsp = PTROUT(fp);
 	regs->tf_rip = LINUX32_PS_STRINGS - *(p->p_sysent->sv_szsigcode) +
 	    linux_sznonrtsigcode;
-	regs->tf_rflags &= ~PSL_T;
+	regs->tf_rflags &= ~(PSL_T | PSL_D);
 	regs->tf_cs = _ucode32sel;
 	regs->tf_ss = _udatasel;
 	load_ds(_udatasel);
@@ -523,7 +523,7 @@ linux_sendsig(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask)
 	 */
 	regs->tf_rsp = PTROUT(fp);
 	regs->tf_rip = LINUX32_PS_STRINGS - *(p->p_sysent->sv_szsigcode);
-	regs->tf_rflags &= ~PSL_T;
+	regs->tf_rflags &= ~(PSL_T | PSL_D);
 	regs->tf_cs = _ucode32sel;
 	regs->tf_ss = _udatasel;
 	load_ds(_udatasel);
diff --git a/sys/i386/i386/machdep.c b/sys/i386/i386/machdep.c
index 2bbad0c93da..35e963a9feb 100644
--- a/sys/i386/i386/machdep.c
+++ b/sys/i386/i386/machdep.c
@@ -417,7 +417,7 @@ osendsig(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask)
 
 	regs->tf_esp = (int)fp;
 	regs->tf_eip = PS_STRINGS - szosigcode;
-	regs->tf_eflags &= ~PSL_T;
+	regs->tf_eflags &= ~(PSL_T | PSL_D);
 	regs->tf_cs = _ucodesel;
 	regs->tf_ds = _udatasel;
 	regs->tf_es = _udatasel;
@@ -538,7 +538,7 @@ freebsd4_sendsig(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask)
 
 	regs->tf_esp = (int)sfp;
 	regs->tf_eip = PS_STRINGS - szfreebsd4_sigcode;
-	regs->tf_eflags &= ~PSL_T;
+	regs->tf_eflags &= ~(PSL_T | PSL_D);
 	regs->tf_cs = _ucodesel;
 	regs->tf_ds = _udatasel;
 	regs->tf_es = _udatasel;
@@ -674,7 +674,7 @@ sendsig(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask)
 
 	regs->tf_esp = (int)sfp;
 	regs->tf_eip = PS_STRINGS - *(p->p_sysent->sv_szsigcode);
-	regs->tf_eflags &= ~PSL_T;
+	regs->tf_eflags &= ~(PSL_T | PSL_D);
 	regs->tf_cs = _ucodesel;
 	regs->tf_ds = _udatasel;
 	regs->tf_es = _udatasel;
diff --git a/sys/i386/linux/linux_sysvec.c b/sys/i386/linux/linux_sysvec.c
index b2c42eaa5d1..379b4877ff1 100644
--- a/sys/i386/linux/linux_sysvec.c
+++ b/sys/i386/linux/linux_sysvec.c
@@ -388,7 +388,7 @@ linux_rt_sendsig(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask)
 	regs->tf_esp = (int)fp;
 	regs->tf_eip = PS_STRINGS - *(p->p_sysent->sv_szsigcode) +
 	    linux_sznonrtsigcode;
-	regs->tf_eflags &= ~(PSL_T | PSL_VM);
+	regs->tf_eflags &= ~(PSL_T | PSL_VM | PSL_D);
 	regs->tf_cs = _ucodesel;
 	regs->tf_ds = _udatasel;
 	regs->tf_es = _udatasel;
@@ -507,7 +507,7 @@ linux_sendsig(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask)
 	 */
 	regs->tf_esp = (int)fp;
 	regs->tf_eip = PS_STRINGS - *(p->p_sysent->sv_szsigcode);
-	regs->tf_eflags &= ~(PSL_T | PSL_VM);
+	regs->tf_eflags &= ~(PSL_T | PSL_VM | PSL_D);
 	regs->tf_cs = _ucodesel;
 	regs->tf_ds = _udatasel;
 	regs->tf_es = _udatasel;
diff --git a/sys/i386/svr4/svr4_machdep.c b/sys/i386/svr4/svr4_machdep.c
index 79a7cbce2e7..50e6ad21229 100644
--- a/sys/i386/svr4/svr4_machdep.c
+++ b/sys/i386/svr4/svr4_machdep.c
@@ -497,13 +497,13 @@ svr4_sendsig(catcher, ksi, mask)
 	     svr4_szsigcode);
 	tf->tf_cs = GSEL(GUSERLDT_SEL, SEL_UPL);
 
-	tf->tf_eflags &= ~(PSL_T|PSL_VM|PSL_AC);
+	tf->tf_eflags &= ~(PSL_T|PSL_VM|PSL_AC|PSL_D);
 	tf->tf_esp = (int)fp;
 	tf->tf_ss = GSEL(GUSERLDT_SEL, SEL_UPL);
 #else
 	tf->tf_esp = (int)fp;
 	tf->tf_eip = (int)(((char *)PS_STRINGS) - *(p->p_sysent->sv_szsigcode));
-	tf->tf_eflags &= ~PSL_T;
+	tf->tf_eflags &= ~(PSL_T | PSL_D);
 	tf->tf_cs = _ucodesel;
 	tf->tf_ds = _udatasel;
 	tf->tf_es = _udatasel;
diff --git a/sys/pc98/pc98/machdep.c b/sys/pc98/pc98/machdep.c
index c158e4f915f..35996473bd0 100644
--- a/sys/pc98/pc98/machdep.c
+++ b/sys/pc98/pc98/machdep.c
@@ -385,7 +385,7 @@ osendsig(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask)
 
 	regs->tf_esp = (int)fp;
 	regs->tf_eip = PS_STRINGS - szosigcode;
-	regs->tf_eflags &= ~PSL_T;
+	regs->tf_eflags &= ~(PSL_T | PSL_D);
 	regs->tf_cs = _ucodesel;
 	regs->tf_ds = _udatasel;
 	regs->tf_es = _udatasel;
@@ -506,7 +506,7 @@ freebsd4_sendsig(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask)
 
 	regs->tf_esp = (int)sfp;
 	regs->tf_eip = PS_STRINGS - szfreebsd4_sigcode;
-	regs->tf_eflags &= ~PSL_T;
+	regs->tf_eflags &= ~(PSL_T | PSL_D);
 	regs->tf_cs = _ucodesel;
 	regs->tf_ds = _udatasel;
 	regs->tf_es = _udatasel;
@@ -642,7 +642,7 @@ sendsig(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask)
 
 	regs->tf_esp = (int)sfp;
 	regs->tf_eip = PS_STRINGS - *(p->p_sysent->sv_szsigcode);
-	regs->tf_eflags &= ~PSL_T;
+	regs->tf_eflags &= ~(PSL_T | PSL_D);
 	regs->tf_cs = _ucodesel;
 	regs->tf_ds = _udatasel;
 	regs->tf_es = _udatasel;