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- lwp_need_userret(): only do it if ONPROC and !curlwp, and explain why. 

- Use signotify() in a couple more places.
This commit is contained in:
ad 2019-11-21 18:17:36 +00:00
parent 298a9247c2
commit e57dd2ba56
2 changed files with 27 additions and 14 deletions
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29
sys/kern/kern_lwp.c
View File

@ -1,7 +1,7 @@
/* $NetBSD: kern_lwp.c,v 1.208 2019/11/14 16:23:52 maxv Exp $ */
/* $NetBSD: kern_lwp.c,v 1.209 2019/11/21 18:17:36 ad Exp $ */
/*-
* Copyright (c) 2001, 2006, 2007, 2008, 2009 The NetBSD Foundation, Inc.
* Copyright (c) 2001, 2006, 2007, 2008, 2009, 2019 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
@ -211,7 +211,7 @@
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: kern_lwp.c,v 1.208 2019/11/14 16:23:52 maxv Exp $");
__KERNEL_RCSID(0, "$NetBSD: kern_lwp.c,v 1.209 2019/11/21 18:17:36 ad Exp $");
#include "opt_ddb.h"
#include "opt_lockdebug.h"
@ -1147,7 +1147,7 @@ lwp_exit(struct lwp *l)
firstsig(&p->p_sigpend.sp_set) != 0) {
LIST_FOREACH(l2, &p->p_lwps, l_sibling) {
lwp_lock(l2);
l2->l_flag |= LW_PENDSIG;
signotify(l2);
lwp_unlock(l2);
}
}
@ -1616,15 +1616,26 @@ lwp_userret(struct lwp *l)
void
lwp_need_userret(struct lwp *l)
{
KASSERT(!cpu_intr_p());
KASSERT(lwp_locked(l, NULL));
/*
* Since the tests in lwp_userret() are done unlocked, make sure
* that the condition will be seen before forcing the LWP to enter
* kernel mode.
* If the LWP is in any state other than LSONPROC, we know that it
* is executing in-kernel and will hit userret() on the way out.
*
* If the LWP is curlwp, then we know we'll be back out to userspace
* soon (can't be called from a hardware interrupt here).
*
* Otherwise, we can't be sure what the LWP is doing, so first make
* sure the update to l_flag will be globally visible, and then
* force the LWP to take a trip through trap() where it will do
* userret().
*/
membar_producer();
cpu_signotify(l);
if (l->l_stat == LSONPROC && l != curlwp) {
membar_producer();
cpu_signotify(l);
}
}
/*

12
sys/kern/kern_sig.c
View File

@ -1,7 +1,7 @@
/* $NetBSD: kern_sig.c,v 1.379 2019/11/20 19:37:53 pgoyette Exp $ */
/* $NetBSD: kern_sig.c,v 1.380 2019/11/21 18:17:36 ad Exp $ */
/*-
* Copyright (c) 2006, 2007, 2008 The NetBSD Foundation, Inc.
* Copyright (c) 2006, 2007, 2008, 2019 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
@ -70,7 +70,7 @@
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: kern_sig.c,v 1.379 2019/11/20 19:37:53 pgoyette Exp $");
__KERNEL_RCSID(0, "$NetBSD: kern_sig.c,v 1.380 2019/11/21 18:17:36 ad Exp $");
#include "opt_ptrace.h"
#include "opt_dtrace.h"
@ -710,6 +710,9 @@ sigclearall(struct proc *p, const sigset_t *mask, ksiginfoq_t *kq)
* current LWP. May be called unlocked provided that LW_PENDSIG is set,
* and that the signal has been posted to the appopriate queue before
* LW_PENDSIG is set.
*
* This should only ever be called with (l == curlwp), unless the
* result does not matter (procfs, sysctl).
*/
int
sigispending(struct lwp *l, int signo)
@ -1133,7 +1136,7 @@ sigpost(struct lwp *l, sig_t action, int prop, int sig)
* Have the LWP check for signals. This ensures that even if no LWP
* is found to take the signal immediately, it should be taken soon.
*/
l->l_flag |= LW_PENDSIG;
signotify(l);
/*
* SIGCONT can be masked, but if LWP is stopped, it needs restart.
@ -1167,7 +1170,6 @@ sigpost(struct lwp *l, sig_t action, int prop, int sig)
switch (l->l_stat) {
case LSRUN:
case LSONPROC:
lwp_need_userret(l);
rv = 1;
break;