Module Name: src
Committed By: ad
Date: Sat Feb 15 18:12:15 UTC 2020
Modified Files:
src/sys/arch/vax/vax: pmap.c
src/sys/ddb: db_proc.c
src/sys/kern: init_main.c kern_exit.c kern_idle.c kern_lwp.c
kern_resource.c kern_sleepq.c kern_softint.c kern_synch.c
src/sys/rump/librump/rumpkern: lwproc.c scheduler.c
src/sys/sys: lwp.h
Log Message:
- Move the LW_RUNNING flag back into l_pflag: updating l_flag without lock
in softint_dispatch() is risky. May help with the "softint screwup"
panic.
- Correct the memory barriers around zombies switching into oblivion.
To generate a diff of this commit:
cvs rdiff -u -r1.188 -r1.189 src/sys/arch/vax/vax/pmap.c
cvs rdiff -u -r1.9 -r1.10 src/sys/ddb/db_proc.c
cvs rdiff -u -r1.519 -r1.520 src/sys/kern/init_main.c
cvs rdiff -u -r1.282 -r1.283 src/sys/kern/kern_exit.c
cvs rdiff -u -r1.31 -r1.32 src/sys/kern/kern_idle.c
cvs rdiff -u -r1.226 -r1.227 src/sys/kern/kern_lwp.c
cvs rdiff -u -r1.184 -r1.185 src/sys/kern/kern_resource.c
cvs rdiff -u -r1.60 -r1.61 src/sys/kern/kern_sleepq.c
cvs rdiff -u -r1.59 -r1.60 src/sys/kern/kern_softint.c
cvs rdiff -u -r1.338 -r1.339 src/sys/kern/kern_synch.c
cvs rdiff -u -r1.43 -r1.44 src/sys/rump/librump/rumpkern/lwproc.c
cvs rdiff -u -r1.49 -r1.50 src/sys/rump/librump/rumpkern/scheduler.c
cvs rdiff -u -r1.201 -r1.202 src/sys/sys/lwp.h
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sys/arch/vax/vax/pmap.c
diff -u src/sys/arch/vax/vax/pmap.c:1.188 src/sys/arch/vax/vax/pmap.c:1.189
--- src/sys/arch/vax/vax/pmap.c:1.188 Wed Jan 8 17:38:42 2020
+++ src/sys/arch/vax/vax/pmap.c Sat Feb 15 18:12:14 2020
@@ -1,4 +1,4 @@
-/* $NetBSD: pmap.c,v 1.188 2020/01/08 17:38:42 ad Exp $ */
+/* $NetBSD: pmap.c,v 1.189 2020/02/15 18:12:14 ad Exp $ */
/*
* Copyright (c) 1994, 1998, 1999, 2003 Ludd, University of Lule}, Sweden.
* All rights reserved.
@@ -25,7 +25,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: pmap.c,v 1.188 2020/01/08 17:38:42 ad Exp $");
+__KERNEL_RCSID(0, "$NetBSD: pmap.c,v 1.189 2020/02/15 18:12:14 ad Exp $");
#include "opt_ddb.h"
#include "opt_cputype.h"
@@ -699,7 +699,7 @@ pmap_vax_swappable(struct lwp *l, struct
return false;
if (l->l_proc->p_vmspace->vm_map.pmap == pm)
return false;
- if ((l->l_flag & LW_RUNNING) != 0)
+ if ((l->l_pflag & LP_RUNNING) != 0)
return false;
if (l->l_class != SCHED_OTHER)
return false;
Index: src/sys/ddb/db_proc.c
diff -u src/sys/ddb/db_proc.c:1.9 src/sys/ddb/db_proc.c:1.10
--- src/sys/ddb/db_proc.c:1.9 Wed Jan 8 17:38:42 2020
+++ src/sys/ddb/db_proc.c Sat Feb 15 18:12:14 2020
@@ -1,7 +1,7 @@
-/* $NetBSD: db_proc.c,v 1.9 2020/01/08 17:38:42 ad Exp $ */
+/* $NetBSD: db_proc.c,v 1.10 2020/02/15 18:12:14 ad Exp $ */
/*-
- * Copyright (c) 2009 The NetBSD Foundation, Inc.
+ * Copyright (c) 2009, 2020 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
@@ -61,7 +61,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: db_proc.c,v 1.9 2020/01/08 17:38:42 ad Exp $");
+__KERNEL_RCSID(0, "$NetBSD: db_proc.c,v 1.10 2020/02/15 18:12:14 ad Exp $");
#ifndef _KERNEL
#include <stdbool.h>
@@ -196,7 +196,7 @@ db_show_all_procs(db_expr_t addr, bool h
sizeof(db_nbuf));
}
run = (l.l_stat == LSONPROC ||
- (l.l_flag & LW_RUNNING) != 0);
+ (l.l_pflag & LP_RUNNING) != 0);
if (l.l_cpu != NULL) {
db_read_bytes((db_addr_t)
&l.l_cpu->ci_data.cpu_index,
@@ -254,7 +254,7 @@ db_show_all_procs(db_expr_t addr, bool h
wbuf[0] = '\0';
}
run = (l.l_stat == LSONPROC ||
- (l.l_flag & LW_RUNNING) != 0);
+ (l.l_pflag & LP_RUNNING) != 0);
db_read_bytes((db_addr_t)&p.p_emul->e_name,
sizeof(ename), (char *)&ename);
@@ -332,7 +332,7 @@ db_show_proc(db_expr_t addr, bool haddr,
db_read_bytes((db_addr_t)lp, sizeof(l), (char *)&l);
run = (l.l_stat == LSONPROC ||
- (l.l_flag & LW_RUNNING) != 0);
+ (l.l_pflag & LP_RUNNING) != 0);
db_printf("%slwp %d", (run ? "> " : " "), l.l_lid);
if (l.l_name != NULL) {
Index: src/sys/kern/init_main.c
diff -u src/sys/kern/init_main.c:1.519 src/sys/kern/init_main.c:1.520
--- src/sys/kern/init_main.c:1.519 Tue Jan 28 16:35:39 2020
+++ src/sys/kern/init_main.c Sat Feb 15 18:12:15 2020
@@ -1,4 +1,4 @@
-/* $NetBSD: init_main.c,v 1.519 2020/01/28 16:35:39 ad Exp $ */
+/* $NetBSD: init_main.c,v 1.520 2020/02/15 18:12:15 ad Exp $ */
/*-
* Copyright (c) 2008, 2009, 2019 The NetBSD Foundation, Inc.
@@ -97,7 +97,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: init_main.c,v 1.519 2020/01/28 16:35:39 ad Exp $");
+__KERNEL_RCSID(0, "$NetBSD: init_main.c,v 1.520 2020/02/15 18:12:15 ad Exp $");
#include "opt_ddb.h"
#include "opt_inet.h"
@@ -290,7 +290,7 @@ main(void)
#ifndef LWP0_CPU_INFO
l->l_cpu = curcpu();
#endif
- l->l_flag |= LW_RUNNING;
+ l->l_pflag |= LP_RUNNING;
/*
* Attempt to find console and initialize
Index: src/sys/kern/kern_exit.c
diff -u src/sys/kern/kern_exit.c:1.282 src/sys/kern/kern_exit.c:1.283
--- src/sys/kern/kern_exit.c:1.282 Wed Jan 29 15:47:52 2020
+++ src/sys/kern/kern_exit.c Sat Feb 15 18:12:15 2020
@@ -1,7 +1,7 @@
-/* $NetBSD: kern_exit.c,v 1.282 2020/01/29 15:47:52 ad Exp $ */
+/* $NetBSD: kern_exit.c,v 1.283 2020/02/15 18:12:15 ad Exp $ */
/*-
- * Copyright (c) 1998, 1999, 2006, 2007, 2008 The NetBSD Foundation, Inc.
+ * Copyright (c) 1998, 1999, 2006, 2007, 2008, 2020 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
@@ -67,7 +67,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: kern_exit.c,v 1.282 2020/01/29 15:47:52 ad Exp $");
+__KERNEL_RCSID(0, "$NetBSD: kern_exit.c,v 1.283 2020/02/15 18:12:15 ad Exp $");
#include "opt_ktrace.h"
#include "opt_dtrace.h"
@@ -592,9 +592,6 @@ exit1(struct lwp *l, int exitcode, int s
*/
cpu_lwp_free(l, 1);
- /* For the LW_RUNNING check in lwp_free(). */
- membar_exit();
-
/* Switch away into oblivion. */
lwp_lock(l);
spc_lock(l->l_cpu);
Index: src/sys/kern/kern_idle.c
diff -u src/sys/kern/kern_idle.c:1.31 src/sys/kern/kern_idle.c:1.32
--- src/sys/kern/kern_idle.c:1.31 Sat Jan 25 20:29:43 2020
+++ src/sys/kern/kern_idle.c Sat Feb 15 18:12:15 2020
@@ -1,4 +1,4 @@
-/* $NetBSD: kern_idle.c,v 1.31 2020/01/25 20:29:43 ad Exp $ */
+/* $NetBSD: kern_idle.c,v 1.32 2020/02/15 18:12:15 ad Exp $ */
/*-
* Copyright (c)2002, 2006, 2007 YAMAMOTO Takashi,
@@ -28,7 +28,7 @@
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: kern_idle.c,v 1.31 2020/01/25 20:29:43 ad Exp $");
+__KERNEL_RCSID(0, "$NetBSD: kern_idle.c,v 1.32 2020/02/15 18:12:15 ad Exp $");
#include <sys/param.h>
#include <sys/cpu.h>
@@ -57,7 +57,7 @@ idle_loop(void *dummy)
binuptime(&l->l_stime);
spc->spc_flags |= SPCF_RUNNING;
KASSERT(l->l_stat == LSONPROC);
- KASSERT((l->l_flag & LW_RUNNING) != 0);
+ KASSERT((l->l_pflag & LP_RUNNING) != 0);
lwp_unlock(l);
/*
@@ -120,7 +120,7 @@ create_idle_lwp(struct cpu_info *ci)
* takes an interrupt before it calls idle_loop().
*/
l->l_stat = LSONPROC;
- l->l_flag |= LW_RUNNING;
+ l->l_pflag |= LP_RUNNING;
ci->ci_onproc = l;
}
lwp_unlock(l);
Index: src/sys/kern/kern_lwp.c
diff -u src/sys/kern/kern_lwp.c:1.226 src/sys/kern/kern_lwp.c:1.227
--- src/sys/kern/kern_lwp.c:1.226 Sat Feb 15 17:13:55 2020
+++ src/sys/kern/kern_lwp.c Sat Feb 15 18:12:15 2020
@@ -1,4 +1,4 @@
-/* $NetBSD: kern_lwp.c,v 1.226 2020/02/15 17:13:55 ad Exp $ */
+/* $NetBSD: kern_lwp.c,v 1.227 2020/02/15 18:12:15 ad Exp $ */
/*-
* Copyright (c) 2001, 2006, 2007, 2008, 2009, 2019, 2020
@@ -80,7 +80,7 @@
* LWP. The LWP may in fact be executing on a processor, may be
* sleeping or idle. It is expected to take the necessary action to
* stop executing or become "running" again within a short timeframe.
- * The LW_RUNNING flag in lwp::l_flag indicates that an LWP is running.
+ * The LP_RUNNING flag in lwp::l_pflag indicates that an LWP is running.
* Importantly, it indicates that its state is tied to a CPU.
*
* LSZOMB:
@@ -211,7 +211,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: kern_lwp.c,v 1.226 2020/02/15 17:13:55 ad Exp $");
+__KERNEL_RCSID(0, "$NetBSD: kern_lwp.c,v 1.227 2020/02/15 18:12:15 ad Exp $");
#include "opt_ddb.h"
#include "opt_lockdebug.h"
@@ -1044,16 +1044,26 @@ lwp_start(lwp_t *l, int flags)
void
lwp_startup(struct lwp *prev, struct lwp *new_lwp)
{
+ kmutex_t *lock;
KASSERTMSG(new_lwp == curlwp, "l %p curlwp %p prevlwp %p", new_lwp, curlwp, prev);
KASSERT(kpreempt_disabled());
KASSERT(prev != NULL);
- KASSERT((prev->l_flag & LW_RUNNING) != 0);
+ KASSERT((prev->l_pflag & LP_RUNNING) != 0);
KASSERT(curcpu()->ci_mtx_count == -2);
- /* Immediately mark previous LWP as no longer running, and unlock. */
- prev->l_flag &= ~LW_RUNNING;
- lwp_unlock(prev);
+ /*
+ * Immediately mark the previous LWP as no longer running and unlock
+ * (to keep lock wait times short as possible). If a zombie, don't
+ * touch after clearing LP_RUNNING as it could be reaped by another
+ * CPU. Issue a memory barrier to ensure this.
+ */
+ lock = prev->l_mutex;
+ if (__predict_false(prev->l_stat == LSZOMB)) {
+ membar_sync();
+ }
+ prev->l_pflag &= ~LP_RUNNING;
+ mutex_spin_exit(lock);
/* Correct spin mutex count after mi_switch(). */
curcpu()->ci_mtx_count = 0;
@@ -1224,8 +1234,6 @@ lwp_exit(struct lwp *l)
cpu_lwp_free(l, 0);
if (current) {
- /* For the LW_RUNNING check in lwp_free(). */
- membar_exit();
/* Switch away into oblivion. */
lwp_lock(l);
spc_lock(l->l_cpu);
@@ -1304,8 +1312,8 @@ lwp_free(struct lwp *l, bool recycle, bo
* all locks to avoid deadlock against interrupt handlers on
* the target CPU.
*/
- membar_enter();
- while (__predict_false((l->l_flag & LW_RUNNING) != 0)) {
+ membar_consumer();
+ while (__predict_false((l->l_pflag & LP_RUNNING) != 0)) {
SPINLOCK_BACKOFF_HOOK;
}
#endif
@@ -1371,7 +1379,7 @@ lwp_migrate(lwp_t *l, struct cpu_info *t
KASSERT(tci != NULL);
/* If LWP is still on the CPU, it must be handled like LSONPROC */
- if ((l->l_flag & LW_RUNNING) != 0) {
+ if ((l->l_pflag & LP_RUNNING) != 0) {
lstat = LSONPROC;
}
Index: src/sys/kern/kern_resource.c
diff -u src/sys/kern/kern_resource.c:1.184 src/sys/kern/kern_resource.c:1.185
--- src/sys/kern/kern_resource.c:1.184 Wed Jan 8 17:38:42 2020
+++ src/sys/kern/kern_resource.c Sat Feb 15 18:12:15 2020
@@ -1,4 +1,4 @@
-/* $NetBSD: kern_resource.c,v 1.184 2020/01/08 17:38:42 ad Exp $ */
+/* $NetBSD: kern_resource.c,v 1.185 2020/02/15 18:12:15 ad Exp $ */
/*-
* Copyright (c) 1982, 1986, 1991, 1993
@@ -37,7 +37,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: kern_resource.c,v 1.184 2020/01/08 17:38:42 ad Exp $");
+__KERNEL_RCSID(0, "$NetBSD: kern_resource.c,v 1.185 2020/02/15 18:12:15 ad Exp $");
#include <sys/param.h>
#include <sys/systm.h>
@@ -506,7 +506,7 @@ calcru(struct proc *p, struct timeval *u
LIST_FOREACH(l, &p->p_lwps, l_sibling) {
lwp_lock(l);
bintime_add(&tm, &l->l_rtime);
- if ((l->l_flag & LW_RUNNING) != 0 &&
+ if ((l->l_pflag & LP_RUNNING) != 0 &&
(l->l_pflag & (LP_INTR | LP_TIMEINTR)) != LP_INTR) {
struct bintime diff;
/*
Index: src/sys/kern/kern_sleepq.c
diff -u src/sys/kern/kern_sleepq.c:1.60 src/sys/kern/kern_sleepq.c:1.61
--- src/sys/kern/kern_sleepq.c:1.60 Sat Feb 1 19:29:27 2020
+++ src/sys/kern/kern_sleepq.c Sat Feb 15 18:12:15 2020
@@ -1,4 +1,4 @@
-/* $NetBSD: kern_sleepq.c,v 1.60 2020/02/01 19:29:27 christos Exp $ */
+/* $NetBSD: kern_sleepq.c,v 1.61 2020/02/15 18:12:15 ad Exp $ */
/*-
* Copyright (c) 2006, 2007, 2008, 2009, 2019, 2020 The NetBSD Foundation, Inc.
@@ -35,7 +35,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: kern_sleepq.c,v 1.60 2020/02/01 19:29:27 christos Exp $");
+__KERNEL_RCSID(0, "$NetBSD: kern_sleepq.c,v 1.61 2020/02/15 18:12:15 ad Exp $");
#include <sys/param.h>
#include <sys/kernel.h>
@@ -143,7 +143,7 @@ sleepq_remove(sleepq_t *sq, lwp_t *l)
* If the LWP is still on the CPU, mark it as LSONPROC. It may be
* about to call mi_switch(), in which case it will yield.
*/
- if ((l->l_flag & LW_RUNNING) != 0) {
+ if ((l->l_pflag & LP_RUNNING) != 0) {
l->l_stat = LSONPROC;
l->l_slptime = 0;
lwp_setlock(l, spc->spc_lwplock);
Index: src/sys/kern/kern_softint.c
diff -u src/sys/kern/kern_softint.c:1.59 src/sys/kern/kern_softint.c:1.60
--- src/sys/kern/kern_softint.c:1.59 Sun Jan 26 18:52:55 2020
+++ src/sys/kern/kern_softint.c Sat Feb 15 18:12:15 2020
@@ -1,4 +1,4 @@
-/* $NetBSD: kern_softint.c,v 1.59 2020/01/26 18:52:55 ad Exp $ */
+/* $NetBSD: kern_softint.c,v 1.60 2020/02/15 18:12:15 ad Exp $ */
/*-
* Copyright (c) 2007, 2008, 2019, 2020 The NetBSD Foundation, Inc.
@@ -170,7 +170,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: kern_softint.c,v 1.59 2020/01/26 18:52:55 ad Exp $");
+__KERNEL_RCSID(0, "$NetBSD: kern_softint.c,v 1.60 2020/02/15 18:12:15 ad Exp $");
#include <sys/param.h>
#include <sys/proc.h>
@@ -842,7 +842,7 @@ softint_dispatch(lwp_t *pinned, int s)
lwp_t *l;
#ifdef DIAGNOSTIC
- if ((pinned->l_flag & LW_RUNNING) == 0 || curlwp->l_stat != LSIDL) {
+ if ((pinned->l_pflag & LP_RUNNING) == 0 || curlwp->l_stat != LSIDL) {
struct lwp *onproc = curcpu()->ci_onproc;
int s2 = splhigh();
printf("curcpu=%d, spl=%d curspl=%d\n"
@@ -881,7 +881,7 @@ softint_dispatch(lwp_t *pinned, int s)
membar_producer(); /* for calcru */
l->l_pflag |= LP_TIMEINTR;
}
- l->l_flag |= LW_RUNNING;
+ l->l_pflag |= LP_RUNNING;
softint_execute(si, l, s);
if (timing) {
binuptime(&now);
@@ -911,7 +911,7 @@ softint_dispatch(lwp_t *pinned, int s)
/* NOTREACHED */
}
l->l_switchto = NULL;
- l->l_flag &= ~LW_RUNNING;
+ l->l_pflag &= ~LP_RUNNING;
}
#endif /* !__HAVE_FAST_SOFTINTS */
Index: src/sys/kern/kern_synch.c
diff -u src/sys/kern/kern_synch.c:1.338 src/sys/kern/kern_synch.c:1.339
--- src/sys/kern/kern_synch.c:1.338 Fri Jan 24 20:05:15 2020
+++ src/sys/kern/kern_synch.c Sat Feb 15 18:12:15 2020
@@ -1,4 +1,4 @@
-/* $NetBSD: kern_synch.c,v 1.338 2020/01/24 20:05:15 ad Exp $ */
+/* $NetBSD: kern_synch.c,v 1.339 2020/02/15 18:12:15 ad Exp $ */
/*-
* Copyright (c) 1999, 2000, 2004, 2006, 2007, 2008, 2009, 2019
@@ -69,7 +69,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: kern_synch.c,v 1.338 2020/01/24 20:05:15 ad Exp $");
+__KERNEL_RCSID(0, "$NetBSD: kern_synch.c,v 1.339 2020/02/15 18:12:15 ad Exp $");
#include "opt_kstack.h"
#include "opt_dtrace.h"
@@ -484,17 +484,15 @@ nextlwp(struct cpu_info *ci, struct sche
sched_dequeue(newl);
KASSERT(lwp_locked(newl, spc->spc_mutex));
KASSERT(newl->l_cpu == ci);
- newl->l_stat = LSONPROC;
- newl->l_flag |= LW_RUNNING;
lwp_setlock(newl, spc->spc_lwplock);
spc->spc_flags &= ~(SPCF_SWITCHCLEAR | SPCF_IDLE);
} else {
newl = ci->ci_data.cpu_idlelwp;
- newl->l_stat = LSONPROC;
- newl->l_flag |= LW_RUNNING;
spc->spc_flags = (spc->spc_flags & ~SPCF_SWITCHCLEAR) |
SPCF_IDLE;
}
+ newl->l_stat = LSONPROC;
+ newl->l_pflag |= LP_RUNNING;
/*
* Only clear want_resched if there are no pending (slow) software
@@ -515,7 +513,7 @@ nextlwp(struct cpu_info *ci, struct sche
* NOTE: l->l_cpu is not changed in this routine, because an LWP never
* changes its own l_cpu (that would screw up curcpu on many ports and could
* cause all kinds of other evil stuff). l_cpu is always changed by some
- * other actor, when it's known the LWP is not running (the LW_RUNNING flag
+ * other actor, when it's known the LWP is not running (the LP_RUNNING flag
* is checked under lock).
*/
void
@@ -524,6 +522,7 @@ mi_switch(lwp_t *l)
struct cpu_info *ci;
struct schedstate_percpu *spc;
struct lwp *newl;
+ kmutex_t *lock;
int oldspl;
struct bintime bt;
bool returning;
@@ -538,7 +537,7 @@ mi_switch(lwp_t *l)
binuptime(&bt);
KASSERTMSG(l == curlwp, "l %p curlwp %p", l, curlwp);
- KASSERT((l->l_flag & LW_RUNNING) != 0);
+ KASSERT((l->l_pflag & LP_RUNNING) != 0);
KASSERT(l->l_cpu == curcpu() || l->l_stat == LSRUN);
ci = curcpu();
spc = &ci->ci_schedstate;
@@ -567,7 +566,7 @@ mi_switch(lwp_t *l)
/* There are pending soft interrupts, so pick one. */
newl = softint_picklwp();
newl->l_stat = LSONPROC;
- newl->l_flag |= LW_RUNNING;
+ newl->l_pflag |= LP_RUNNING;
}
#endif /* !__HAVE_FAST_SOFTINTS */
@@ -694,7 +693,7 @@ mi_switch(lwp_t *l)
*/
if (returning) {
/* Keep IPL_SCHED after this; MD code will fix up. */
- l->l_flag &= ~LW_RUNNING;
+ l->l_pflag &= ~LP_RUNNING;
lwp_unlock(l);
} else {
/* A normal LWP: save old VM context. */
@@ -732,12 +731,20 @@ mi_switch(lwp_t *l)
KASSERT(ci->ci_mtx_count == -2);
/*
- * Immediately mark the previous LWP as no longer running,
- * and unlock it. We'll still be at IPL_SCHED afterwards.
+ * Immediately mark the previous LWP as no longer running
+ * and unlock (to keep lock wait times short as possible).
+ * We'll still be at IPL_SCHED afterwards. If a zombie,
+ * don't touch after clearing LP_RUNNING as it could be
+ * reaped by another CPU. Issue a memory barrier to ensure
+ * this.
*/
- KASSERT((prevlwp->l_flag & LW_RUNNING) != 0);
- prevlwp->l_flag &= ~LW_RUNNING;
- lwp_unlock(prevlwp);
+ KASSERT((prevlwp->l_pflag & LP_RUNNING) != 0);
+ lock = prevlwp->l_mutex;
+ if (__predict_false(prevlwp->l_stat == LSZOMB)) {
+ membar_sync();
+ }
+ prevlwp->l_pflag &= ~LP_RUNNING;
+ mutex_spin_exit(lock);
/*
* Switched away - we have new curlwp.
@@ -833,7 +840,7 @@ setrunnable(struct lwp *l)
* If the LWP is still on the CPU, mark it as LSONPROC. It may be
* about to call mi_switch(), in which case it will yield.
*/
- if ((l->l_flag & LW_RUNNING) != 0) {
+ if ((l->l_pflag & LP_RUNNING) != 0) {
l->l_stat = LSONPROC;
l->l_slptime = 0;
lwp_unlock(l);
Index: src/sys/rump/librump/rumpkern/lwproc.c
diff -u src/sys/rump/librump/rumpkern/lwproc.c:1.43 src/sys/rump/librump/rumpkern/lwproc.c:1.44
--- src/sys/rump/librump/rumpkern/lwproc.c:1.43 Wed Jan 8 17:38:42 2020
+++ src/sys/rump/librump/rumpkern/lwproc.c Sat Feb 15 18:12:15 2020
@@ -1,4 +1,4 @@
-/* $NetBSD: lwproc.c,v 1.43 2020/01/08 17:38:42 ad Exp $ */
+/* $NetBSD: lwproc.c,v 1.44 2020/02/15 18:12:15 ad Exp $ */
/*
* Copyright (c) 2010, 2011 Antti Kantee. All Rights Reserved.
@@ -28,7 +28,7 @@
#define RUMP__CURLWP_PRIVATE
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: lwproc.c,v 1.43 2020/01/08 17:38:42 ad Exp $");
+__KERNEL_RCSID(0, "$NetBSD: lwproc.c,v 1.44 2020/02/15 18:12:15 ad Exp $");
#include <sys/param.h>
#include <sys/atomic.h>
@@ -476,12 +476,12 @@ rump_lwproc_switch(struct lwp *newlwp)
KASSERT(!(l->l_flag & LW_WEXIT) || newlwp);
- if (__predict_false(newlwp && (newlwp->l_flag & LW_RUNNING)))
+ if (__predict_false(newlwp && (newlwp->l_pflag & LP_RUNNING)))
panic("lwp %p (%d:%d) already running",
newlwp, newlwp->l_proc->p_pid, newlwp->l_lid);
if (newlwp == NULL) {
- l->l_flag &= ~LW_RUNNING;
+ l->l_pflag &= ~LP_RUNNING;
l->l_flag |= LW_RUMP_CLEAR;
return;
}
@@ -496,7 +496,7 @@ rump_lwproc_switch(struct lwp *newlwp)
newlwp->l_cpu = newlwp->l_target_cpu = l->l_cpu;
newlwp->l_mutex = l->l_mutex;
- newlwp->l_flag |= LW_RUNNING;
+ newlwp->l_pflag |= LP_RUNNING;
lwproc_curlwpop(RUMPUSER_LWP_SET, newlwp);
curcpu()->ci_curlwp = newlwp;
@@ -513,7 +513,7 @@ rump_lwproc_switch(struct lwp *newlwp)
mutex_exit(newlwp->l_proc->p_lock);
l->l_mutex = &unruntime_lock;
- l->l_flag &= ~LW_RUNNING;
+ l->l_pflag &= ~LP_RUNNING;
l->l_flag &= ~LW_PENDSIG;
l->l_stat = LSRUN;
Index: src/sys/rump/librump/rumpkern/scheduler.c
diff -u src/sys/rump/librump/rumpkern/scheduler.c:1.49 src/sys/rump/librump/rumpkern/scheduler.c:1.50
--- src/sys/rump/librump/rumpkern/scheduler.c:1.49 Wed Jan 8 17:38:42 2020
+++ src/sys/rump/librump/rumpkern/scheduler.c Sat Feb 15 18:12:15 2020
@@ -1,4 +1,4 @@
-/* $NetBSD: scheduler.c,v 1.49 2020/01/08 17:38:42 ad Exp $ */
+/* $NetBSD: scheduler.c,v 1.50 2020/02/15 18:12:15 ad Exp $ */
/*
* Copyright (c) 2010, 2011 Antti Kantee. All Rights Reserved.
@@ -26,7 +26,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: scheduler.c,v 1.49 2020/01/08 17:38:42 ad Exp $");
+__KERNEL_RCSID(0, "$NetBSD: scheduler.c,v 1.50 2020/02/15 18:12:15 ad Exp $");
#include <sys/param.h>
#include <sys/atomic.h>
@@ -409,7 +409,7 @@ rump_unschedule()
/* release lwp0 */
rump_unschedule_cpu(&lwp0);
lwp0.l_mutex = &unruntime_lock;
- lwp0.l_flag &= ~LW_RUNNING;
+ lwp0.l_pflag &= ~LP_RUNNING;
lwp0rele();
rump_lwproc_curlwp_clear(&lwp0);
Index: src/sys/sys/lwp.h
diff -u src/sys/sys/lwp.h:1.201 src/sys/sys/lwp.h:1.202
--- src/sys/sys/lwp.h:1.201 Sat Feb 15 17:13:55 2020
+++ src/sys/sys/lwp.h Sat Feb 15 18:12:15 2020
@@ -1,4 +1,4 @@
-/* $NetBSD: lwp.h,v 1.201 2020/02/15 17:13:55 ad Exp $ */
+/* $NetBSD: lwp.h,v 1.202 2020/02/15 18:12:15 ad Exp $ */
/*
* Copyright (c) 2001, 2006, 2007, 2008, 2009, 2010, 2019, 2020
@@ -235,7 +235,10 @@ extern int maxlwp __read_mostly; /* max
#endif /* _KERNEL || _KMEMUSER */
-/* These flags are kept in l_flag. */
+/*
+ * These flags are kept in l_flag, and they are modified only with the LWP
+ * locked.
+ */
#define LW_IDLE 0x00000001 /* Idle lwp. */
#define LW_LWPCTL 0x00000002 /* Adjust lwpctl in userret */
#define LW_CVLOCKDEBUG 0x00000004 /* Waker does lockdebug */
@@ -250,11 +253,15 @@ extern int maxlwp __read_mostly; /* max
#define LW_CANCELLED 0x02000000 /* tsleep should not sleep */
#define LW_WREBOOT 0x08000000 /* System is rebooting, please suspend */
#define LW_UNPARKED 0x10000000 /* Unpark op pending */
-#define LW_RUNNING 0x20000000 /* Active on a CPU */
#define LW_RUMP_CLEAR 0x40000000 /* Clear curlwp in RUMP scheduler */
#define LW_RUMP_QEXIT 0x80000000 /* LWP should exit ASAP */
-/* The second set of flags is kept in l_pflag. */
+/*
+ * The second set of flags is kept in l_pflag, and they are modified only by
+ * the LWP itself, or modified when it's known the LWP cannot be running.
+ * LP_RUNNING is typically updated with the LWP locked, but not always in
+ * the case of soft interrupt handlers.
+ */
#define LP_KTRACTIVE 0x00000001 /* Executing ktrace operation */
#define LP_KTRCSW 0x00000002 /* ktrace context switch marker */
#define LP_KTRCSWUSER 0x00000004 /* ktrace context switch marker */
@@ -267,10 +274,14 @@ extern int maxlwp __read_mostly; /* max
#define LP_SINGLESTEP 0x00000400 /* Single step thread in ptrace(2) */
#define LP_TIMEINTR 0x00010000 /* Time this soft interrupt */
#define LP_PREEMPTING 0x00020000 /* mi_switch called involuntarily */
+#define LP_RUNNING 0x20000000 /* Active on a CPU */
#define LP_TELEPORT 0x40000000 /* Teleport to new CPU on preempt() */
#define LP_BOUND 0x80000000 /* Bound to a CPU */
-/* The third set is kept in l_prflag. */
+/*
+ * The third set of flags is kept in l_prflag and they are modified only
+ * with p_lock held.
+ */
#define LPR_DETACHED 0x00800000 /* Won't be waited for. */
#define LPR_CRMOD 0x00000100 /* Credentials modified */
