In r197963, a race with thread being selected for signal delivery

while in kernel mode, and later changing signal mask to block the
signal, was fixed for sigprocmask(2) and ptread_exit(3). The same race
exists for sigreturn(2), setcontext(2) and swapcontext(2) syscalls.

Use kern_sigprocmask() instead of direct manipulation of td_sigmask to
reschedule newly blocked signals, closing the race.

Reviewed by:	davidxu
Tested by:	pho
MFC after:	1 month

16 files changed, 77 insertions, 185 deletions

diff --git a/sys/amd64/amd64/machdep.c b/sys/amd64/amd64/machdep.c
index 95db5d2..ebb7805 100644
--- a/sys/amd64/amd64/machdep.c
+++ b/sys/amd64/amd64/machdep.c
@@ -415,7 +415,7 @@ sigreturn(td, uap)
 	ucontext_t uc;
 	struct proc *p = td->td_proc;
 	struct trapframe *regs;
-	const ucontext_t *ucp;
+	ucontext_t *ucp;
 	long rflags;
 	int cs, error, ret;
 	ksiginfo_t ksi;
@@ -478,7 +478,6 @@ sigreturn(td, uap)
 	td->td_pcb->pcb_fsbase = ucp->uc_mcontext.mc_fsbase;
 	td->td_pcb->pcb_gsbase = ucp->uc_mcontext.mc_gsbase;
 
-	PROC_LOCK(p);
 #if defined(COMPAT_43)
 	if (ucp->uc_mcontext.mc_onstack & 1)
 		td->td_sigstk.ss_flags |= SS_ONSTACK;
@@ -486,10 +485,7 @@ sigreturn(td, uap)
 		td->td_sigstk.ss_flags &= ~SS_ONSTACK;
 #endif
 
-	td->td_sigmask = ucp->uc_sigmask;
-	SIG_CANTMASK(td->td_sigmask);
-	signotify(td);
-	PROC_UNLOCK(p);
+	kern_sigprocmask(td, SIG_SETMASK, &ucp->uc_sigmask, NULL, 0);
 	td->td_pcb->pcb_flags |= PCB_FULLCTX;
 	td->td_pcb->pcb_full_iret = 1;
 	return (EJUSTRETURN);
diff --git a/sys/amd64/ia32/ia32_signal.c b/sys/amd64/ia32/ia32_signal.c
index d7c1dd5..10ec641 100644
--- a/sys/amd64/ia32/ia32_signal.c
+++ b/sys/amd64/ia32/ia32_signal.c
@@ -244,10 +244,8 @@ freebsd32_setcontext(struct thread *td, struct freebsd32_setcontext_args *uap)
 		if (ret == 0) {
 			ret = ia32_set_mcontext(td, &uc.uc_mcontext);
 			if (ret == 0) {
-				SIG_CANTMASK(uc.uc_sigmask);
-				PROC_LOCK(td->td_proc);
-				td->td_sigmask = uc.uc_sigmask;
-				PROC_UNLOCK(td->td_proc);
+				kern_sigprocmask(td, SIG_SETMASK,
+				    &uc.uc_sigmask, NULL, 0);
 			}
 		}
 	}
@@ -273,10 +271,8 @@ freebsd32_swapcontext(struct thread *td, struct freebsd32_swapcontext_args *uap)
 			if (ret == 0) {
 				ret = ia32_set_mcontext(td, &uc.uc_mcontext);
 				if (ret == 0) {
-					SIG_CANTMASK(uc.uc_sigmask);
-					PROC_LOCK(td->td_proc);
-					td->td_sigmask = uc.uc_sigmask;
-					PROC_UNLOCK(td->td_proc);
+					kern_sigprocmask(td, SIG_SETMASK,
+					    &uc.uc_sigmask, NULL, 0);
 				}
 			}
 		}
@@ -544,9 +540,8 @@ freebsd4_freebsd32_sigreturn(td, uap)
 	} */ *uap;
 {
 	struct ia32_ucontext4 uc;
-	struct proc *p = td->td_proc;
 	struct trapframe *regs;
-	const struct ia32_ucontext4 *ucp;
+	struct ia32_ucontext4 *ucp;
 	int cs, eflags, error;
 	ksiginfo_t ksi;
 
@@ -610,11 +605,7 @@ freebsd4_freebsd32_sigreturn(td, uap)
 	regs->tf_fs = ucp->uc_mcontext.mc_fs;
 	regs->tf_gs = ucp->uc_mcontext.mc_gs;
 
-	PROC_LOCK(p);
-	td->td_sigmask = ucp->uc_sigmask;
-	SIG_CANTMASK(td->td_sigmask);
-	signotify(td);
-	PROC_UNLOCK(p);
+	kern_sigprocmask(td, SIG_SETMASK, &ucp->uc_sigmask, NULL, 0);
 	td->td_pcb->pcb_full_iret = 1;
 	return (EJUSTRETURN);
 }
@@ -631,9 +622,8 @@ freebsd32_sigreturn(td, uap)
 	} */ *uap;
 {
 	struct ia32_ucontext uc;
-	struct proc *p = td->td_proc;
 	struct trapframe *regs;
-	const struct ia32_ucontext *ucp;
+	struct ia32_ucontext *ucp;
 	int cs, eflags, error, ret;
 	ksiginfo_t ksi;
 
@@ -702,11 +692,7 @@ freebsd32_sigreturn(td, uap)
 	regs->tf_gs = ucp->uc_mcontext.mc_gs;
 	regs->tf_flags = TF_HASSEGS;
 
-	PROC_LOCK(p);
-	td->td_sigmask = ucp->uc_sigmask;
-	SIG_CANTMASK(td->td_sigmask);
-	signotify(td);
-	PROC_UNLOCK(p);
+	kern_sigprocmask(td, SIG_SETMASK, &ucp->uc_sigmask, NULL, 0);
 	td->td_pcb->pcb_full_iret = 1;
 	return (EJUSTRETURN);
 }
diff --git a/sys/amd64/linux32/linux32_sysvec.c b/sys/amd64/linux32/linux32_sysvec.c
index 54a04ee..6e3e326 100644
--- a/sys/amd64/linux32/linux32_sysvec.c
+++ b/sys/amd64/linux32/linux32_sysvec.c
@@ -565,9 +565,9 @@ linux_sendsig(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask)
 int
 linux_sigreturn(struct thread *td, struct linux_sigreturn_args *args)
 {
-	struct proc *p = td->td_proc;
 	struct l_sigframe frame;
 	struct trapframe *regs;
+	sigset_t bmask;
 	l_sigset_t lmask;
 	int eflags, i;
 	ksiginfo_t ksi;
@@ -623,11 +623,8 @@ linux_sigreturn(struct thread *td, struct linux_sigreturn_args *args)
 	lmask.__bits[0] = frame.sf_sc.sc_mask;
 	for (i = 0; i < (LINUX_NSIG_WORDS-1); i++)
 		lmask.__bits[i+1] = frame.sf_extramask[i];
-	PROC_LOCK(p);
-	linux_to_bsd_sigset(&lmask, &td->td_sigmask);
-	SIG_CANTMASK(td->td_sigmask);
-	signotify(td);
-	PROC_UNLOCK(p);
+	linux_to_bsd_sigset(&lmask, &bmask);
+	kern_sigprocmask(td, SIG_SETMASK, &bmask, NULL, 0);
 
 	/*
 	 * Restore signal context.
@@ -666,9 +663,9 @@ linux_sigreturn(struct thread *td, struct linux_sigreturn_args *args)
 int
 linux_rt_sigreturn(struct thread *td, struct linux_rt_sigreturn_args *args)
 {
-	struct proc *p = td->td_proc;
 	struct l_ucontext uc;
 	struct l_sigcontext *context;
+	sigset_t bmask;
 	l_stack_t *lss;
 	stack_t ss;
 	struct trapframe *regs;
@@ -725,11 +722,8 @@ linux_rt_sigreturn(struct thread *td, struct linux_rt_sigreturn_args *args)
 		return(EINVAL);
 	}
 
-	PROC_LOCK(p);
-	linux_to_bsd_sigset(&uc.uc_sigmask, &td->td_sigmask);
-	SIG_CANTMASK(td->td_sigmask);
-	signotify(td);
-	PROC_UNLOCK(p);
+	linux_to_bsd_sigset(&uc.uc_sigmask, &bmask);
+	kern_sigprocmask(td, SIG_SETMASK, &bmask, NULL, 0);
 
 	/*
 	 * Restore signal context
diff --git a/sys/arm/arm/machdep.c b/sys/arm/arm/machdep.c
index 597cdf5..f49319e 100644
--- a/sys/arm/arm/machdep.c
+++ b/sys/arm/arm/machdep.c
@@ -605,7 +605,6 @@ sigreturn(td, uap)
 		const struct __ucontext *sigcntxp;
 	} */ *uap;
 {
-	struct proc *p = td->td_proc;
 	struct sigframe sf;
 	struct trapframe *tf;
 	int spsr;
@@ -627,11 +626,7 @@ sigreturn(td, uap)
 	set_mcontext(td, &sf.sf_uc.uc_mcontext);
 
 	/* Restore signal mask. */
-	PROC_LOCK(p);
-	td->td_sigmask = sf.sf_uc.uc_sigmask;
-	SIG_CANTMASK(td->td_sigmask);
-	signotify(td);
-	PROC_UNLOCK(p);
+	kern_sigprocmask(td, SIG_SETMASK, &sf.sf_uc.uc_sigmask, NULL, 0);
 
 	return (EJUSTRETURN);
 }
diff --git a/sys/compat/freebsd32/freebsd32_misc.c b/sys/compat/freebsd32/freebsd32_misc.c
index 9f6b16d..37fa079 100644
--- a/sys/compat/freebsd32/freebsd32_misc.c
+++ b/sys/compat/freebsd32/freebsd32_misc.c
@@ -2482,7 +2482,7 @@ ofreebsd32_sigprocmask(struct thread *td,
 	int error;
 
 	OSIG2SIG(uap->mask, set);
-	error = kern_sigprocmask(td, uap->how, &set, &oset, 1);
+	error = kern_sigprocmask(td, uap->how, &set, &oset, SIGPROCMASK_OLD);
 	SIG2OSIG(oset, td->td_retval[0]);
 	return (error);
 }
@@ -2546,15 +2546,11 @@ int
 ofreebsd32_sigblock(struct thread *td,
 			    struct ofreebsd32_sigblock_args *uap)
 {
-	struct proc *p = td->td_proc;
-	sigset_t set;
+	sigset_t set, oset;
 
 	OSIG2SIG(uap->mask, set);
-	SIG_CANTMASK(set);
-	PROC_LOCK(p);
-	SIG2OSIG(td->td_sigmask, td->td_retval[0]);
-	SIGSETOR(td->td_sigmask, set);
-	PROC_UNLOCK(p);
+	kern_sigprocmask(td, SIG_BLOCK, &set, &oset, 0);
+	SIG2OSIG(oset, td->td_retval[0]);
 	return (0);
 }
 
@@ -2562,16 +2558,11 @@ int
 ofreebsd32_sigsetmask(struct thread *td,
 			      struct ofreebsd32_sigsetmask_args *uap)
 {
-	struct proc *p = td->td_proc;
-	sigset_t set;
+	sigset_t set, oset;
 
 	OSIG2SIG(uap->mask, set);
-	SIG_CANTMASK(set);
-	PROC_LOCK(p);
-	SIG2OSIG(td->td_sigmask, td->td_retval[0]);
-	SIGSETLO(td->td_sigmask, set);
-	signotify(td);
-	PROC_UNLOCK(p);
+	kern_sigprocmask(td, SIG_SETMASK, &set, &oset, 0);
+	SIG2OSIG(oset, td->td_retval[0]);
 	return (0);
 }
 
diff --git a/sys/i386/i386/machdep.c b/sys/i386/i386/machdep.c
index 96c8f25..5c294eb 100644
--- a/sys/i386/i386/machdep.c
+++ b/sys/i386/i386/machdep.c
@@ -756,7 +756,6 @@ osigreturn(td, uap)
 	struct osigcontext sc;
 	struct trapframe *regs;
 	struct osigcontext *scp;
-	struct proc *p = td->td_proc;
 	int eflags, error;
 	ksiginfo_t ksi;
 
@@ -856,17 +855,14 @@ osigreturn(td, uap)
 	regs->tf_eip = scp->sc_pc;
 	regs->tf_eflags = eflags;
 
-	PROC_LOCK(p);
 #if defined(COMPAT_43)
 	if (scp->sc_onstack & 1)
 		td->td_sigstk.ss_flags |= SS_ONSTACK;
 	else
 		td->td_sigstk.ss_flags &= ~SS_ONSTACK;
 #endif
-	SIGSETOLD(td->td_sigmask, scp->sc_mask);
-	SIG_CANTMASK(td->td_sigmask);
-	signotify(td);
-	PROC_UNLOCK(p);
+	kern_sigprocmask(td, SIG_SETMASK, (sigset_t *)&scp->sc_mask, NULL,
+	    SIGPROCMASK_OLD);
 	return (EJUSTRETURN);
 }
 #endif /* COMPAT_43 */
@@ -883,9 +879,8 @@ freebsd4_sigreturn(td, uap)
 	} */ *uap;
 {
 	struct ucontext4 uc;
-	struct proc *p = td->td_proc;
 	struct trapframe *regs;
-	const struct ucontext4 *ucp;
+	struct ucontext4 *ucp;
 	int cs, eflags, error;
 	ksiginfo_t ksi;
 
@@ -973,18 +968,13 @@ freebsd4_sigreturn(td, uap)
 		bcopy(&ucp->uc_mcontext.mc_fs, regs, sizeof(*regs));
 	}
 
-	PROC_LOCK(p);
 #if defined(COMPAT_43)
 	if (ucp->uc_mcontext.mc_onstack & 1)
 		td->td_sigstk.ss_flags |= SS_ONSTACK;
 	else
 		td->td_sigstk.ss_flags &= ~SS_ONSTACK;
 #endif
-
-	td->td_sigmask = ucp->uc_sigmask;
-	SIG_CANTMASK(td->td_sigmask);
-	signotify(td);
-	PROC_UNLOCK(p);
+	kern_sigprocmask(td, SIG_SETMASK, &ucp->uc_sigmask, NULL, 0);
 	return (EJUSTRETURN);
 }
 #endif	/* COMPAT_FREEBSD4 */
@@ -1000,9 +990,8 @@ sigreturn(td, uap)
 	} */ *uap;
 {
 	ucontext_t uc;
-	struct proc *p = td->td_proc;
 	struct trapframe *regs;
-	const ucontext_t *ucp;
+	ucontext_t *ucp;
 	int cs, eflags, error, ret;
 	ksiginfo_t ksi;
 
@@ -1094,7 +1083,6 @@ sigreturn(td, uap)
 		bcopy(&ucp->uc_mcontext.mc_fs, regs, sizeof(*regs));
 	}
 
-	PROC_LOCK(p);
 #if defined(COMPAT_43)
 	if (ucp->uc_mcontext.mc_onstack & 1)
 		td->td_sigstk.ss_flags |= SS_ONSTACK;
@@ -1102,10 +1090,7 @@ sigreturn(td, uap)
 		td->td_sigstk.ss_flags &= ~SS_ONSTACK;
 #endif
 
-	td->td_sigmask = ucp->uc_sigmask;
-	SIG_CANTMASK(td->td_sigmask);
-	signotify(td);
-	PROC_UNLOCK(p);
+	kern_sigprocmask(td, SIG_SETMASK, &ucp->uc_sigmask, NULL, 0);
 	return (EJUSTRETURN);
 }
 
diff --git a/sys/i386/linux/linux_sysvec.c b/sys/i386/linux/linux_sysvec.c
index d07f655..069b5bb 100644
--- a/sys/i386/linux/linux_sysvec.c
+++ b/sys/i386/linux/linux_sysvec.c
@@ -667,10 +667,10 @@ linux_sendsig(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask)
 int
 linux_sigreturn(struct thread *td, struct linux_sigreturn_args *args)
 {
-	struct proc *p = td->td_proc;
 	struct l_sigframe frame;
 	struct trapframe *regs;
 	l_sigset_t lmask;
+	sigset_t bmask;
 	int eflags, i;
 	ksiginfo_t ksi;
 
@@ -725,11 +725,8 @@ linux_sigreturn(struct thread *td, struct linux_sigreturn_args *args)
 	lmask.__bits[0] = frame.sf_sc.sc_mask;
 	for (i = 0; i < (LINUX_NSIG_WORDS-1); i++)
 		lmask.__bits[i+1] = frame.sf_extramask[i];
-	PROC_LOCK(p);
-	linux_to_bsd_sigset(&lmask, &td->td_sigmask);
-	SIG_CANTMASK(td->td_sigmask);
-	signotify(td);
-	PROC_UNLOCK(p);
+	linux_to_bsd_sigset(&lmask, &bmask);
+	kern_sigprocmask(td, SIG_SETMASK, &bmask, NULL, 0);
 
 	/*
 	 * Restore signal context.
@@ -767,9 +764,9 @@ linux_sigreturn(struct thread *td, struct linux_sigreturn_args *args)
 int
 linux_rt_sigreturn(struct thread *td, struct linux_rt_sigreturn_args *args)
 {
-	struct proc *p = td->td_proc;
 	struct l_ucontext uc;
 	struct l_sigcontext *context;
+	sigset_t bmask;
 	l_stack_t *lss;
 	stack_t ss;
 	struct trapframe *regs;
@@ -826,11 +823,8 @@ linux_rt_sigreturn(struct thread *td, struct linux_rt_sigreturn_args *args)
 		return(EINVAL);
 	}
 
-	PROC_LOCK(p);
-	linux_to_bsd_sigset(&uc.uc_sigmask, &td->td_sigmask);
-	SIG_CANTMASK(td->td_sigmask);
-	signotify(td);
-	PROC_UNLOCK(p);
+	linux_to_bsd_sigset(&uc.uc_sigmask, &bmask);
+	kern_sigprocmask(td, SIG_SETMASK, &bmask, NULL, 0);
 
 	/*
 	 * Restore signal context
diff --git a/sys/ia64/ia64/machdep.c b/sys/ia64/ia64/machdep.c
index 67ca3c2..299c9ec 100644
--- a/sys/ia64/ia64/machdep.c
+++ b/sys/ia64/ia64/machdep.c
@@ -1056,11 +1056,9 @@ sigreturn(struct thread *td,
 {
 	ucontext_t uc;
 	struct trapframe *tf;
-	struct proc *p;
 	struct pcb *pcb;
 
 	tf = td->td_frame;
-	p = td->td_proc;
 	pcb = td->td_pcb;
 
 	/*
@@ -1072,17 +1070,13 @@ sigreturn(struct thread *td,
 
 	set_mcontext(td, &uc.uc_mcontext);
 
-	PROC_LOCK(p);
 #if defined(COMPAT_43)
 	if (sigonstack(tf->tf_special.sp))
 		td->td_sigstk.ss_flags |= SS_ONSTACK;
 	else
 		td->td_sigstk.ss_flags &= ~SS_ONSTACK;
 #endif
-	td->td_sigmask = uc.uc_sigmask;
-	SIG_CANTMASK(td->td_sigmask);
-	signotify(td);
-	PROC_UNLOCK(p);
+	kern_sigprocmask(td, SIG_SETMASK, &uc.uc_sigmask, NULL, 0);
 
 	return (EJUSTRETURN);
 }
diff --git a/sys/kern/kern_context.c b/sys/kern/kern_context.c
index f951fca..6628eb6 100644
--- a/sys/kern/kern_context.c
+++ b/sys/kern/kern_context.c
@@ -89,10 +89,8 @@ setcontext(struct thread *td, struct setcontext_args *uap)
 		if (ret == 0) {
 			ret = set_mcontext(td, &uc.uc_mcontext);
 			if (ret == 0) {
-				SIG_CANTMASK(uc.uc_sigmask);
-				PROC_LOCK(td->td_proc);
-				td->td_sigmask = uc.uc_sigmask;
-				PROC_UNLOCK(td->td_proc);
+				kern_sigprocmask(td, SIG_SETMASK, &uc.uc_sigmask,
+				    NULL, 0);
 			}
 		}
 	}
@@ -118,10 +116,8 @@ swapcontext(struct thread *td, struct swapcontext_args *uap)
 			if (ret == 0) {
 				ret = set_mcontext(td, &uc.uc_mcontext);
 				if (ret == 0) {
-					SIG_CANTMASK(uc.uc_sigmask);
-					PROC_LOCK(td->td_proc);
-					td->td_sigmask = uc.uc_sigmask;
-					PROC_UNLOCK(td->td_proc);
+					kern_sigprocmask(td, SIG_SETMASK,
+					    &uc.uc_sigmask, NULL, 0);
 				}
 			}
 		}
diff --git a/sys/kern/kern_sig.c b/sys/kern/kern_sig.c
index a453b55..d0249f5 100644
--- a/sys/kern/kern_sig.c
+++ b/sys/kern/kern_sig.c
@@ -1396,15 +1396,11 @@ osigblock(td, uap)
 	register struct thread *td;
 	struct osigblock_args *uap;
 {
-	struct proc *p = td->td_proc;
-	sigset_t set;
+	sigset_t set, oset;
 
 	OSIG2SIG(uap->mask, set);
-	SIG_CANTMASK(set);
-	PROC_LOCK(p);
-	SIG2OSIG(td->td_sigmask, td->td_retval[0]);
-	SIGSETOR(td->td_sigmask, set);
-	PROC_UNLOCK(p);
+	kern_sigprocmask(td, SIG_BLOCK, &set, &oset, 0);
+	SIG2OSIG(oset, td->td_retval[0]);
 	return (0);
 }
 
@@ -1418,16 +1414,11 @@ osigsetmask(td, uap)
 	struct thread *td;
 	struct osigsetmask_args *uap;
 {
-	struct proc *p = td->td_proc;
-	sigset_t set;
+	sigset_t set, oset;
 
 	OSIG2SIG(uap->mask, set);
-	SIG_CANTMASK(set);
-	PROC_LOCK(p);
-	SIG2OSIG(td->td_sigmask, td->td_retval[0]);
-	SIGSETLO(td->td_sigmask, set);
-	signotify(td);
-	PROC_UNLOCK(p);
+	kern_sigprocmask(td, SIG_SETMASK, &set, &oset, 0);
+	SIG2OSIG(oset, td->td_retval[0]);
 	return (0);
 }
 #endif /* COMPAT_43 */
@@ -1845,6 +1836,7 @@ void
 trapsignal(struct thread *td, ksiginfo_t *ksi)
 {
 	struct sigacts *ps;
+	sigset_t mask;
 	struct proc *p;
 	int sig;
 	int code;
@@ -1868,8 +1860,11 @@ trapsignal(struct thread *td, ksiginfo_t *ksi)
 		(*p->p_sysent->sv_sendsig)(ps->ps_sigact[_SIG_IDX(sig)], 
 				ksi, &td->td_sigmask);
 		SIGSETOR(td->td_sigmask, ps->ps_catchmask[_SIG_IDX(sig)]);
-		if (!SIGISMEMBER(ps->ps_signodefer, sig))
-			SIGADDSET(td->td_sigmask, sig);
+		if (!SIGISMEMBER(ps->ps_signodefer, sig)) {
+			SIGEMPTYSET(mask);
+			SIGADDSET(mask, sig);
+			kern_sigprocmask(td, SIG_BLOCK, &mask, NULL, 0);
+		}
 		if (SIGISMEMBER(ps->ps_sigreset, sig)) {
 			/*
 			 * See kern_sigaction() for origin of this code.
@@ -2683,7 +2678,7 @@ postsig(sig)
 	struct sigacts *ps;
 	sig_t action;
 	ksiginfo_t ksi;
-	sigset_t returnmask;
+	sigset_t returnmask, mask;
 
 	KASSERT(sig != 0, ("postsig"));
 
@@ -2738,9 +2733,15 @@ postsig(sig)
 		} else
 			returnmask = td->td_sigmask;
 
-		SIGSETOR(td->td_sigmask, ps->ps_catchmask[_SIG_IDX(sig)]);
-		if (!SIGISMEMBER(ps->ps_signodefer, sig))
-			SIGADDSET(td->td_sigmask, sig);
+		kern_sigprocmask(td, SIG_BLOCK,
+		    &ps->ps_catchmask[_SIG_IDX(sig)], NULL,
+		    SIGPROCMASK_PROC_LOCKED);
+		if (!SIGISMEMBER(ps->ps_signodefer, sig)) {
+			SIGEMPTYSET(mask);
+			SIGADDSET(mask, sig);
+			kern_sigprocmask(td, SIG_BLOCK, &mask, NULL,
+			    SIGPROCMASK_PROC_LOCKED);
+		}
 
 		if (SIGISMEMBER(ps->ps_sigreset, sig)) {
 			/*
diff --git a/sys/mips/mips/pm_machdep.c b/sys/mips/mips/pm_machdep.c
index 9fb1fec..dc30f4c 100644
--- a/sys/mips/mips/pm_machdep.c
+++ b/sys/mips/mips/pm_machdep.c
@@ -213,13 +213,11 @@ int
 sigreturn(struct thread *td, struct sigreturn_args *uap)
 {
 	struct trapframe *regs;
-	const ucontext_t *ucp;
-	struct proc *p;
+	ucontext_t *ucp;
 	ucontext_t uc;
 	int error;
 
 	ucp = &uc;
-	p = td->td_proc;
 
 	error = copyin(uap->sigcntxp, &uc, sizeof(uc));
 	if (error != 0)
@@ -229,7 +227,7 @@ sigreturn(struct thread *td, struct sigreturn_args *uap)
 
 /* #ifdef DEBUG */
 	if (ucp->uc_mcontext.mc_regs[ZERO] != UCONTEXT_MAGIC) {
-		printf("sigreturn: pid %d, ucp %p\n", p->p_pid, ucp);
+		printf("sigreturn: pid %d, ucp %p\n", td->td_proc->p_pid, ucp);
 		printf("  old sp %x ra %x pc %x\n",
 		    regs->sp, regs->ra, regs->pc);
 		printf("  new sp %x ra %x pc %x z %x\n",
@@ -253,11 +251,8 @@ sigreturn(struct thread *td, struct sigreturn_args *uap)
 	regs->mullo = ucp->uc_mcontext.mullo;
 	regs->mulhi = ucp->uc_mcontext.mulhi;
 
-	PROC_LOCK(p);
-	td->td_sigmask = ucp->uc_sigmask;
-	SIG_CANTMASK(td->td_sigmask);
-	signotify(td);
-	PROC_UNLOCK(p);
+	kern_sigprocmask(td, SIG_SETMASK, &ucp->uc_sigmask, NULL, 0);
+
 	return(EJUSTRETURN);
 }
 
diff --git a/sys/pc98/pc98/machdep.c b/sys/pc98/pc98/machdep.c
index f052cee..f07eb6b 100644
--- a/sys/pc98/pc98/machdep.c
+++ b/sys/pc98/pc98/machdep.c
@@ -686,7 +686,6 @@ osigreturn(td, uap)
 	struct osigcontext sc;
 	struct trapframe *regs;
 	struct osigcontext *scp;
-	struct proc *p = td->td_proc;
 	int eflags, error;
 	ksiginfo_t ksi;
 
@@ -786,17 +785,14 @@ osigreturn(td, uap)
 	regs->tf_eip = scp->sc_pc;
 	regs->tf_eflags = eflags;
 
-	PROC_LOCK(p);
 #if defined(COMPAT_43)
 	if (scp->sc_onstack & 1)
 		td->td_sigstk.ss_flags |= SS_ONSTACK;
 	else
 		td->td_sigstk.ss_flags &= ~SS_ONSTACK;
 #endif
-	SIGSETOLD(td->td_sigmask, scp->sc_mask);
-	SIG_CANTMASK(td->td_sigmask);
-	signotify(td);
-	PROC_UNLOCK(p);
+	kern_sigprocmask(td, SIG_SETMASK, (sigset_t *)&scp->sc_mask, NULL,
+	    SIGPROCMASK_OLD);
 	return (EJUSTRETURN);
 }
 #endif /* COMPAT_43 */
@@ -813,9 +809,8 @@ freebsd4_sigreturn(td, uap)
 	} */ *uap;
 {
 	struct ucontext4 uc;
-	struct proc *p = td->td_proc;
 	struct trapframe *regs;
-	const struct ucontext4 *ucp;
+	struct ucontext4 *ucp;
 	int cs, eflags, error;
 	ksiginfo_t ksi;
 
@@ -903,18 +898,13 @@ freebsd4_sigreturn(td, uap)
 		bcopy(&ucp->uc_mcontext.mc_fs, regs, sizeof(*regs));
 	}
 
-	PROC_LOCK(p);
 #if defined(COMPAT_43)
 	if (ucp->uc_mcontext.mc_onstack & 1)
 		td->td_sigstk.ss_flags |= SS_ONSTACK;
 	else
 		td->td_sigstk.ss_flags &= ~SS_ONSTACK;
 #endif
-
-	td->td_sigmask = ucp->uc_sigmask;
-	SIG_CANTMASK(td->td_sigmask);
-	signotify(td);
-	PROC_UNLOCK(p);
+	kern_sigprocmask(td, SIG_SETMASK, &ucp->uc_sigmask, NULL, 0);
 	return (EJUSTRETURN);
 }
 #endif	/* COMPAT_FREEBSD4 */
@@ -930,9 +920,8 @@ sigreturn(td, uap)
 	} */ *uap;
 {
 	ucontext_t uc;
-	struct proc *p = td->td_proc;
 	struct trapframe *regs;
-	const ucontext_t *ucp;
+	ucontext_t *ucp;
 	int cs, eflags, error, ret;
 	ksiginfo_t ksi;
 
@@ -1024,18 +1013,14 @@ sigreturn(td, uap)
 		bcopy(&ucp->uc_mcontext.mc_fs, regs, sizeof(*regs));
 	}
 
-	PROC_LOCK(p);
 #if defined(COMPAT_43)
 	if (ucp->uc_mcontext.mc_onstack & 1)
 		td->td_sigstk.ss_flags |= SS_ONSTACK;
 	else
 		td->td_sigstk.ss_flags &= ~SS_ONSTACK;
 #endif
+	kern_sigprocmask(td, SIG_SETMASK, &ucp->uc_sigmask, NULL, 0);
 
-	td->td_sigmask = ucp->uc_sigmask;
-	SIG_CANTMASK(td->td_sigmask);
-	signotify(td);
-	PROC_UNLOCK(p);
 	return (EJUSTRETURN);
 }
 
diff --git a/sys/powerpc/aim/machdep.c b/sys/powerpc/aim/machdep.c
index da73dfa..713402e 100644
--- a/sys/powerpc/aim/machdep.c
+++ b/sys/powerpc/aim/machdep.c
@@ -692,7 +692,6 @@ sendsig(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask)
 int
 sigreturn(struct thread *td, struct sigreturn_args *uap)
 {
-	struct proc *p;
 	ucontext_t uc;
 	int error;
 
@@ -707,12 +706,7 @@ sigreturn(struct thread *td, struct sigreturn_args *uap)
 	if (error != 0)
 		return (error);
 
-	p = td->td_proc;
-	PROC_LOCK(p);
-	td->td_sigmask = uc.uc_sigmask;
-	SIG_CANTMASK(td->td_sigmask);
-	signotify(td);
-	PROC_UNLOCK(p);
+	kern_sigprocmask(td, SIG_SETMASK, &uc.uc_sigmask, NULL, 0);
 
 	CTR3(KTR_SIG, "sigreturn: return td=%p pc=%#x sp=%#x",
 	     td, uc.uc_mcontext.mc_srr0, uc.uc_mcontext.mc_gpr[1]);
diff --git a/sys/powerpc/booke/machdep.c b/sys/powerpc/booke/machdep.c
index 8787098..1eace0e 100644
--- a/sys/powerpc/booke/machdep.c
+++ b/sys/powerpc/booke/machdep.c
@@ -665,7 +665,6 @@ set_mcontext(struct thread *td, const mcontext_t *mcp)
 int
 sigreturn(struct thread *td, struct sigreturn_args *uap)
 {
-	struct proc *p;
 	ucontext_t uc;
 	int error;
 
@@ -680,12 +679,7 @@ sigreturn(struct thread *td, struct sigreturn_args *uap)
 	if (error != 0)
 		return (error);
 
-	p = td->td_proc;
-	PROC_LOCK(p);
-	td->td_sigmask = uc.uc_sigmask;
-	SIG_CANTMASK(td->td_sigmask);
-	signotify(td);
-	PROC_UNLOCK(p);
+	kern_sigprocmask(td, SIG_SETMASK, &uc.uc_sigmask, NULL, 0);
 
 	CTR3(KTR_SIG, "sigreturn: return td=%p pc=%#x sp=%#x",
 	    td, uc.uc_mcontext.mc_srr0, uc.uc_mcontext.mc_gpr[1]);
diff --git a/sys/sparc64/sparc64/machdep.c b/sys/sparc64/sparc64/machdep.c
index 49a2bb1..4b55c0e 100644
--- a/sys/sparc64/sparc64/machdep.c
+++ b/sys/sparc64/sparc64/machdep.c
@@ -653,11 +653,7 @@ sigreturn(struct thread *td, struct sigreturn_args *uap)
 	if (error != 0)
 		return (error);
 
-	PROC_LOCK(p);
-	td->td_sigmask = uc.uc_sigmask;
-	SIG_CANTMASK(td->td_sigmask);
-	signotify(td);
-	PROC_UNLOCK(p);
+	kern_sigprocmask(td, SIG_SETMASK, &uc.uc_sigmask, NULL, 0);
 
 	CTR4(KTR_SIG, "sigreturn: return td=%p pc=%#lx sp=%#lx tstate=%#lx",
 	    td, mc->mc_tpc, mc->mc_sp, mc->mc_tstate);
diff --git a/sys/sun4v/sun4v/machdep.c b/sys/sun4v/sun4v/machdep.c
index 5430460..3913d35 100644
--- a/sys/sun4v/sun4v/machdep.c
+++ b/sys/sun4v/sun4v/machdep.c
@@ -667,11 +667,7 @@ sigreturn(struct thread *td, struct sigreturn_args *uap)
 	if (error != 0)
 		return (error);
 
-	PROC_LOCK(p);
-	td->td_sigmask = uc.uc_sigmask;
-	SIG_CANTMASK(td->td_sigmask);
-	signotify(td);
-	PROC_UNLOCK(p);
+	kern_sigprocmask(td, SIG_SETMASK, &uc.uc_sigmask, NULL, 0);
 
 	CTR4(KTR_SIG, "sigreturn: return td=%p pc=%#lx sp=%#lx tstate=%#lx",
 	    td, mc->mc_tpc, mc->mc_sp, mc->mc_tstate);