Date: Wed, 20 Dec 2000 16:21:06 -0500 From: Jake Burkholder <jburkhol@home.com> To: smp@freebsd.org Subject: review: proctree_lock Message-ID: <20001220212106.41C6CBA7D@io.yi.org>
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[-- Attachment #1 --]
Attached is a patch that adds the proctree_lock. This is a lockmgr
lock which protects all parent-child relationships between processes.
Specifically the field p_pptr, and the p_children/p_sibling list.
Dependant functions are proc_reparent(), and stop(). proc_reparent
requires an exclusive hold, stop requires at least a shared hold.
This will allow several of the trivial proc-related system calls to
be made MP-safe.
Please review and test it.
[-- Attachment #2 --]
Index: alpha/alpha/sys_machdep.c
===================================================================
RCS file: /home/ncvs/src/sys/alpha/alpha/sys_machdep.c,v
retrieving revision 1.7
diff -u -r1.7 sys_machdep.c
--- alpha/alpha/sys_machdep.c 2000/01/16 07:07:28 1.7
+++ alpha/alpha/sys_machdep.c 2000/12/18 00:56:24
@@ -173,6 +173,7 @@
if (error)
return (error);
+ PROCTREE_LOCK(PT_SHARED);
if (p->p_pptr) {
s = splimp();
if (p->p_pptr) {
@@ -182,6 +183,7 @@
error = ESRCH;
splx(s);
}
+ PROCTREE_LOCK(PT_RELEASE);
return error;
}
@@ -192,6 +194,7 @@
unsigned long uac;
error = ESRCH;
+ PROCTREE_LOCK(PT_SHARED);
if (p->p_pptr) {
s = splimp();
if (p->p_pptr) {
@@ -200,5 +203,6 @@
}
splx(s);
}
+ PROCTREE_LOCK(PT_RELEASE);
return error;
}
Index: alpha/alpha/vm_machdep.c
===================================================================
RCS file: /home/ncvs/src/sys/alpha/alpha/vm_machdep.c,v
retrieving revision 1.39
diff -u -r1.39 vm_machdep.c
--- alpha/alpha/vm_machdep.c 2000/12/01 18:55:58 1.39
+++ alpha/alpha/vm_machdep.c 2000/12/20 20:56:07
@@ -256,6 +256,18 @@
mtx_enter(&sched_lock, MTX_SPIN);
mtx_exit(&Giant, MTX_DEF | MTX_NOSWITCH);
mtx_assert(&Giant, MA_NOTOWNED);
+
+ /*
+ * We have to wait until after releasing all locks before
+ * changing p_stat. If we block on a mutex while waiting to
+ * release the allproc_lock, then we will be back at SRUN when
+ * we resume here and our parent will never harvest us.
+ */
+ p->p_stat = SZOMB;
+
+ mp_fixme("assumption: p_pptr won't change at this time");
+ wakeup(p->p_pptr);
+
cnt.v_swtch++;
cpu_switch();
panic("cpu_exit");
Index: compat/linprocfs/linprocfs_misc.c
===================================================================
RCS file: /home/ncvs/src/sys/compat/linprocfs/linprocfs_misc.c,v
retrieving revision 1.16
diff -u -r1.16 linprocfs_misc.c
--- compat/linprocfs/linprocfs_misc.c 2000/12/13 20:22:24 1.16
+++ compat/linprocfs/linprocfs_misc.c 2000/12/18 01:33:30
@@ -364,14 +364,18 @@
struct sbuf sb;
char *ps;
int r, xlen;
+ pid_t ppid;
+ PROCTREE_LOCK(PT_SHARED);
+ ppid = p->p_pptr ? p->p_pptr->p_pid : 0;
+ PROCTREE_LOCK(PT_RELEASE);
fill_kinfo_proc(p, &kp);
sbuf_new(&sb, NULL, 1024, 0);
sbuf_printf(&sb, "%d", p->p_pid);
#define PS_ADD(name, fmt, arg) sbuf_printf(&sb, " " fmt, arg)
PS_ADD("comm", "(%s)", p->p_comm);
PS_ADD("statr", "%c", '0'); /* XXX */
- PS_ADD("ppid", "%d", p->p_pptr ? p->p_pptr->p_pid : 0);
+ PS_ADD("ppid", "%d", ppid);
PS_ADD("pgrp", "%d", p->p_pgid);
PS_ADD("session", "%d", p->p_session->s_sid);
PS_ADD("tty", "%d", 0); /* XXX */
@@ -447,6 +451,7 @@
char *state;
int i, r, xlen;
segsz_t lsize;
+ pid_t ppid;
sbuf_new(&sb, NULL, 1024, 0);
@@ -457,6 +462,9 @@
state = state_str[(int)p->p_stat];
mtx_exit(&sched_lock, MTX_SPIN);
+ PROCTREE_LOCK(PT_SHARED);
+ ppid = p->p_pptr ? p->p_pptr->p_pid : 0;
+ PROCTREE_LOCK(PT_RELEASE);
fill_kinfo_proc(p, &kp);
sbuf_printf(&sb, "Name:\t%s\n", p->p_comm); /* XXX escape */
sbuf_printf(&sb, "State:\t%s\n", state);
@@ -465,7 +473,7 @@
* Credentials
*/
sbuf_printf(&sb, "Pid:\t%d\n", p->p_pid);
- sbuf_printf(&sb, "PPid:\t%d\n", p->p_pptr ? p->p_pptr->p_pid : 0);
+ sbuf_printf(&sb, "PPid:\t%d\n", ppid);
sbuf_printf(&sb, "Uid:\t%d %d %d %d\n", p->p_cred->p_ruid,
p->p_ucred->cr_uid,
p->p_cred->p_svuid,
Index: compat/svr4/svr4_misc.c
===================================================================
RCS file: /home/ncvs/src/sys/compat/svr4/svr4_misc.c,v
retrieving revision 1.17
diff -u -r1.17 svr4_misc.c
--- compat/svr4/svr4_misc.c 2000/12/13 00:16:59 1.17
+++ compat/svr4/svr4_misc.c 2000/12/18 01:40:53
@@ -1205,6 +1205,7 @@
loop:
nfound = 0;
+ PROCTREE_LOCK(PT_SHARED);
for (q = p->p_children.lh_first; q != 0; q = q->p_sibling.le_next) {
if (SCARG(uap, id) != WAIT_ANY &&
q->p_pid != SCARG(uap, id) &&
@@ -1216,6 +1217,7 @@
nfound++;
if (q->p_stat == SZOMB &&
((SCARG(uap, options) & (SVR4_WEXITED|SVR4_WTRAPPED)))) {
+ PROCTREE_LOCK(PT_RELEASE);
*retval = 0;
DPRINTF(("found %d\n", q->p_pid));
if ((error = svr4_setinfo(q, q->p_xstat,
@@ -1236,14 +1238,18 @@
* parent a SIGCHLD. The rest of the cleanup will be
* done when the old parent waits on the child.
*/
- if ((q->p_flag & P_TRACED) &&
- q->p_oppid != q->p_pptr->p_pid) {
- t = pfind(q->p_oppid);
- proc_reparent(q, t ? t : initproc);
- q->p_oppid = 0;
- q->p_flag &= ~(P_TRACED | P_WAITED);
- wakeup((caddr_t)q->p_pptr);
- return 0;
+ if (q->p_flag & P_TRACED) {
+ PROCTREE_LOCK(PT_EXCLUSIVE);
+ if (q->p_oppid != q->p_pptr->p_pid) {
+ t = pfind(q->p_oppid);
+ proc_reparent(q, t ? t : initproc);
+ q->p_oppid = 0;
+ q->p_flag &= ~(P_TRACED | P_WAITED);
+ wakeup((caddr_t)q->p_pptr);
+ PROCTREE_LOCK(PT_RELEASE);
+ return 0;
+ }
+ PROCTREE_LOCK(PT_RELEASE);
}
q->p_xstat = 0;
ruadd(&p->p_stats->p_cru, q->p_ru);
@@ -1260,7 +1266,9 @@
LIST_REMOVE(q, p_list); /* off zombproc */
ALLPROC_LOCK(AP_RELEASE);
+ PROCTREE_LOCK(PT_EXCLUSIVE);
LIST_REMOVE(q, p_sibling);
+ PROCTREE_LOCK(PT_RELEASE);
/*
* Decrement the count of procs running with this uid.
Index: i386/i386/vm_machdep.c
===================================================================
RCS file: /home/ncvs/src/sys/i386/i386/vm_machdep.c,v
retrieving revision 1.145
diff -u -r1.145 vm_machdep.c
--- i386/i386/vm_machdep.c 2000/12/08 21:50:09 1.145
+++ i386/i386/vm_machdep.c 2000/12/20 20:56:38
@@ -259,6 +259,18 @@
mtx_enter(&sched_lock, MTX_SPIN);
mtx_exit(&Giant, MTX_DEF | MTX_NOSWITCH);
mtx_assert(&Giant, MA_NOTOWNED);
+
+ /*
+ * We have to wait until after releasing all locks before
+ * changing p_stat. If we block on a mutex while waiting to
+ * release the allproc_lock, then we will be back at SRUN when
+ * we resume here and our parent will never harvest us.
+ */
+ p->p_stat = SZOMB;
+
+ mp_fixme("assumption: p_pptr won't change at this time");
+ wakeup(p->p_pptr);
+
cnt.v_swtch++;
cpu_throw();
panic("cpu_exit");
Index: ia64/ia64/vm_machdep.c
===================================================================
RCS file: /home/ncvs/src/sys/ia64/ia64/vm_machdep.c,v
retrieving revision 1.9
diff -u -r1.9 vm_machdep.c
--- ia64/ia64/vm_machdep.c 2000/11/15 19:44:38 1.9
+++ ia64/ia64/vm_machdep.c 2000/12/20 20:51:19
@@ -306,6 +306,18 @@
mtx_enter(&sched_lock, MTX_SPIN);
mtx_exit(&Giant, MTX_DEF | MTX_NOSWITCH);
mtx_assert(&Giant, MA_NOTOWNED);
+
+ /*
+ * We have to wait until after releasing all locks before
+ * changing p_stat. If we block on a mutex then we will be
+ * back at SRUN when we resume and our parent will never
+ * harvest us.
+ */
+ p->p_stat = SZOMB;
+
+ mp_fixme("assumption: p_pptr won't change at this time");
+ wakeup(p->p_pptr);
+
cnt.v_swtch++;
cpu_switch();
panic("cpu_exit");
Index: kern/kern_exec.c
===================================================================
RCS file: /home/ncvs/src/sys/kern/kern_exec.c,v
retrieving revision 1.120
diff -u -r1.120 kern_exec.c
--- kern/kern_exec.c 2000/11/30 21:06:05 1.120
+++ kern/kern_exec.c 2000/12/18 00:57:06
@@ -267,10 +267,12 @@
* it that it now has its own resources back
*/
p->p_flag |= P_EXEC;
+ PROCTREE_LOCK(PT_SHARED);
if (p->p_pptr && (p->p_flag & P_PPWAIT)) {
p->p_flag &= ~P_PPWAIT;
wakeup((caddr_t)p->p_pptr);
}
+ PROCTREE_LOCK(PT_RELEASE);
/*
* Implement image setuid/setgid.
Index: kern/kern_exit.c
===================================================================
RCS file: /home/ncvs/src/sys/kern/kern_exit.c,v
retrieving revision 1.111
diff -u -r1.111 kern_exit.c
--- kern/kern_exit.c 2000/12/18 07:10:04 1.111
+++ kern/kern_exit.c 2000/12/20 20:53:54
@@ -267,17 +267,10 @@
ALLPROC_LOCK(AP_EXCLUSIVE);
LIST_REMOVE(p, p_list);
LIST_INSERT_HEAD(&zombproc, p, p_list);
-
LIST_REMOVE(p, p_hash);
ALLPROC_LOCK(AP_RELEASE);
- /*
- * We have to wait until after releasing this lock before
- * changing p_stat. If we block on a mutex while waiting to
- * release the allproc_lock, then we will be back at SRUN when
- * we resume here and our parent will never harvest us.
- */
- p->p_stat = SZOMB;
+ PROCTREE_LOCK(PT_EXCLUSIVE);
q = LIST_FIRST(&p->p_children);
if (q) /* only need this if any child is S_ZOMB */
wakeup((caddr_t) initproc);
@@ -343,7 +336,7 @@
psignal(p->p_pptr, SIGCHLD);
}
- wakeup((caddr_t)p->p_pptr);
+ PROCTREE_LOCK(PT_RELEASE);
/*
* Clear curproc after we've done all operations
* that could block, and before tearing down the rest
@@ -419,6 +412,7 @@
return (EINVAL);
loop:
nfound = 0;
+ PROCTREE_LOCK(PT_SHARED);
LIST_FOREACH(p, &q->p_children, p_sibling) {
if (uap->pid != WAIT_ANY &&
p->p_pid != uap->pid && p->p_pgid != -uap->pid)
@@ -440,6 +434,7 @@
mtx_enter(&sched_lock, MTX_SPIN);
if (p->p_stat == SZOMB) {
mtx_exit(&sched_lock, MTX_SPIN);
+ PROCTREE_LOCK(PT_RELEASE);
/* charge childs scheduling cpu usage to parent */
if (curproc->p_pid != 1) {
@@ -466,12 +461,17 @@
* If we got the child via a ptrace 'attach',
* we need to give it back to the old parent.
*/
- if (p->p_oppid && (t = pfind(p->p_oppid))) {
- p->p_oppid = 0;
- proc_reparent(p, t);
- psignal(t, SIGCHLD);
- wakeup((caddr_t)t);
- return (0);
+ if (p->p_oppid) {
+ PROCTREE_LOCK(PT_EXCLUSIVE);
+ if ((t = pfind(p->p_oppid)) != NULL) {
+ p->p_oppid = 0;
+ proc_reparent(p, t);
+ psignal(t, SIGCHLD);
+ wakeup((caddr_t)t);
+ PROCTREE_LOCK(PT_RELEASE);
+ return (0);
+ }
+ PROCTREE_LOCK(PT_RELEASE);
}
p->p_xstat = 0;
ruadd(&q->p_stats->p_cru, p->p_ru);
@@ -519,10 +519,14 @@
* Unlink it from its process group and free it.
*/
leavepgrp(p);
+
ALLPROC_LOCK(AP_EXCLUSIVE);
LIST_REMOVE(p, p_list); /* off zombproc */
ALLPROC_LOCK(AP_RELEASE);
+
+ PROCTREE_LOCK(PT_EXCLUSIVE);
LIST_REMOVE(p, p_sibling);
+ PROCTREE_LOCK(PT_RELEASE);
if (--p->p_procsig->ps_refcnt == 0) {
if (p->p_sigacts != &p->p_addr->u_sigacts)
@@ -545,6 +549,7 @@
if (p->p_stat == SSTOP && (p->p_flag & P_WAITED) == 0 &&
(p->p_flag & P_TRACED || uap->options & WUNTRACED)) {
mtx_exit(&sched_lock, MTX_SPIN);
+ PROCTREE_LOCK(PT_RELEASE);
p->p_flag |= P_WAITED;
q->p_retval[0] = p->p_pid;
#ifdef COMPAT_43
@@ -563,6 +568,7 @@
}
mtx_exit(&sched_lock, MTX_SPIN);
}
+ PROCTREE_LOCK(PT_RELEASE);
if (nfound == 0)
return (ECHILD);
if (uap->options & WNOHANG) {
@@ -575,7 +581,8 @@
}
/*
- * make process 'parent' the new parent of process 'child'.
+ * Make process 'parent' the new parent of process 'child'.
+ * Must be called with an exclusive hold of proctree lock.
*/
void
proc_reparent(child, parent)
@@ -583,6 +590,7 @@
register struct proc *parent;
{
+ PROCTREE_ASSERT(PT_EXCLUSIVE);
if (child->p_pptr == parent)
return;
Index: kern/kern_fork.c
===================================================================
RCS file: /home/ncvs/src/sys/kern/kern_fork.c,v
retrieving revision 1.90
diff -u -r1.90 kern_fork.c
--- kern/kern_fork.c 2000/12/13 00:17:01 1.90
+++ kern/kern_fork.c 2000/12/17 18:58:08
@@ -476,8 +476,10 @@
pptr = initproc;
else
pptr = p1;
+ PROCTREE_LOCK(PT_EXCLUSIVE);
p2->p_pptr = pptr;
LIST_INSERT_HEAD(&pptr->p_children, p2, p_sibling);
+ PROCTREE_LOCK(PT_RELEASE);
LIST_INIT(&p2->p_children);
LIST_INIT(&p2->p_heldmtx);
LIST_INIT(&p2->p_contested);
Index: kern/kern_kthread.c
===================================================================
RCS file: /home/ncvs/src/sys/kern/kern_kthread.c,v
retrieving revision 1.10
diff -u -r1.10 kern_kthread.c
--- kern/kern_kthread.c 2000/12/15 20:08:18 1.10
+++ kern/kern_kthread.c 2000/12/18 04:48:34
@@ -30,6 +30,7 @@
#include <sys/systm.h>
#include <sys/proc.h>
#include <sys/kthread.h>
+#include <sys/lock.h>
#include <sys/resourcevar.h>
#include <sys/signalvar.h>
#include <sys/unistd.h>
@@ -113,7 +114,10 @@
void
kthread_exit(int ecode)
{
+
+ PROCTREE_LOCK(PT_EXCLUSIVE);
proc_reparent(curproc, initproc);
+ PROCTREE_LOCK(PT_RELEASE);
exit1(curproc, W_EXITCODE(ecode, 0));
}
Index: kern/kern_ktrace.c
===================================================================
RCS file: /home/ncvs/src/sys/kern/kern_ktrace.c,v
retrieving revision 1.45
diff -u -r1.45 kern_ktrace.c
--- kern/kern_ktrace.c 2000/12/13 00:17:01 1.45
+++ kern/kern_ktrace.c 2000/12/18 00:13:00
@@ -317,7 +317,6 @@
ret |= ktrsetchildren(curp, p, ops, facs, vp);
else
ret |= ktrops(curp, p, ops, facs, vp);
-
} else {
/*
* by pid
@@ -426,6 +425,7 @@
register int ret = 0;
p = top;
+ PROCTREE_LOCK(PT_SHARED);
for (;;) {
ret |= ktrops(curp, p, ops, facs, vp);
/*
@@ -436,8 +436,10 @@
if (!LIST_EMPTY(&p->p_children))
p = LIST_FIRST(&p->p_children);
else for (;;) {
- if (p == top)
+ if (p == top) {
+ PROCTREE_LOCK(PT_RELEASE);
return (ret);
+ }
if (LIST_NEXT(p, p_sibling)) {
p = LIST_NEXT(p, p_sibling);
break;
Index: kern/kern_proc.c
===================================================================
RCS file: /home/ncvs/src/sys/kern/kern_proc.c,v
retrieving revision 1.79
diff -u -r1.79 kern_proc.c
--- kern/kern_proc.c 2000/12/13 00:17:01 1.79
+++ kern/kern_proc.c 2000/12/18 03:01:57
@@ -73,6 +73,7 @@
struct proclist allproc;
struct proclist zombproc;
struct lock allproc_lock;
+struct lock proctree_lock;
vm_zone_t proc_zone;
vm_zone_t ithread_zone;
@@ -84,6 +85,7 @@
{
lockinit(&allproc_lock, PZERO, "allproc", 0, 0);
+ lockinit(&proctree_lock, PZERO, "proctree", 0, 0);
LIST_INIT(&allproc);
LIST_INIT(&zombproc);
pidhashtbl = hashinit(maxproc / 4, M_PROC, &pidhash);
@@ -106,11 +108,16 @@
inferior(p)
register struct proc *p;
{
+ int rval = 1;
+ PROCTREE_LOCK(PT_SHARED);
for (; p != curproc; p = p->p_pptr)
- if (p->p_pid == 0)
- return (0);
- return (1);
+ if (p->p_pid == 0) {
+ rval = 0;
+ break;
+ }
+ PROCTREE_LOCK(PT_RELEASE);
+ return (rval);
}
/*
@@ -281,6 +288,7 @@
* Check p's parent to see whether p qualifies its own process
* group; if so, adjust count for p's process group.
*/
+ PROCTREE_LOCK(PT_SHARED);
if ((hispgrp = p->p_pptr->p_pgrp) != pgrp &&
hispgrp->pg_session == mysession) {
if (entering)
@@ -303,6 +311,7 @@
else if (--hispgrp->pg_jobc == 0)
orphanpg(hispgrp);
}
+ PROCTREE_LOCK(PT_RELEASE);
}
/*
@@ -414,8 +423,10 @@
kp->ki_rtprio = p->p_rtprio;
kp->ki_runtime = p->p_runtime;
kp->ki_pid = p->p_pid;
+ PROCTREE_LOCK(PT_SHARED);
if (p->p_pptr)
kp->ki_ppid = p->p_pptr->p_pid;
+ PROCTREE_LOCK(PT_RELEASE);
sp = NULL;
if (p->p_pgrp) {
kp->ki_pgid = p->p_pgrp->pg_id;
Index: kern/kern_prot.c
===================================================================
RCS file: /home/ncvs/src/sys/kern/kern_prot.c,v
retrieving revision 1.69
diff -u -r1.69 kern_prot.c
--- kern/kern_prot.c 2000/11/30 19:09:48 1.69
+++ kern/kern_prot.c 2000/12/18 03:44:08
@@ -50,6 +50,7 @@
#include <sys/systm.h>
#include <sys/sysproto.h>
#include <sys/kernel.h>
+#include <sys/lock.h>
#include <sys/proc.h>
#include <sys/malloc.h>
#include <sys/pioctl.h>
@@ -64,9 +65,6 @@
};
#endif
-/*
- * NOT MP SAFE due to p_pptr access
- */
/* ARGSUSED */
int
getpid(p, uap)
@@ -76,7 +74,9 @@
p->p_retval[0] = p->p_pid;
#if defined(COMPAT_43) || defined(COMPAT_SUNOS)
+ PROCTREE_LOCK(PT_SHARED);
p->p_retval[1] = p->p_pptr->p_pid;
+ PROCTREE_LOCK(PT_RELEASE);
#endif
return (0);
}
@@ -93,7 +93,9 @@
struct getppid_args *uap;
{
+ PROCTREE_LOCK(PT_SHARED);
p->p_retval[0] = p->p_pptr->p_pid;
+ PROCTREE_LOCK(PT_RELEASE);
return (0);
}
Index: kern/kern_sig.c
===================================================================
RCS file: /home/ncvs/src/sys/kern/kern_sig.c,v
retrieving revision 1.97
diff -u -r1.97 kern_sig.c
--- kern/kern_sig.c 2000/12/16 21:03:48 1.97
+++ kern/kern_sig.c 2000/12/18 04:48:34
@@ -1158,9 +1158,11 @@
goto out;
SIGDELSET(p->p_siglist, sig);
p->p_xstat = sig;
+ PROCTREE_LOCK(PT_SHARED);
if ((p->p_pptr->p_procsig->ps_flag & PS_NOCLDSTOP) == 0)
psignal(p->p_pptr, SIGCHLD);
stop(p);
+ PROCTREE_LOCK(PT_RELEASE);
goto out;
} else
goto runfast;
@@ -1296,14 +1298,17 @@
* stopped until released by the parent.
*/
p->p_xstat = sig;
+ PROCTREE_LOCK(PT_SHARED);
psignal(p->p_pptr, SIGCHLD);
do {
stop(p);
+ PROCTREE_LOCK(PT_RELEASE);
mtx_enter(&sched_lock, MTX_SPIN);
DROP_GIANT_NOSWITCH();
mi_switch();
mtx_exit(&sched_lock, MTX_SPIN);
PICKUP_GIANT();
+ PROCTREE_LOCK(PT_SHARED);
} while (!trace_req(p)
&& p->p_flag & P_TRACED);
@@ -1369,9 +1374,11 @@
prop & SA_TTYSTOP))
break; /* == ignore */
p->p_xstat = sig;
+ PROCTREE_LOCK(PT_SHARED);
stop(p);
if ((p->p_pptr->p_procsig->ps_flag & PS_NOCLDSTOP) == 0)
psignal(p->p_pptr, SIGCHLD);
+ PROCTREE_LOCK(PT_RELEASE);
mtx_enter(&sched_lock, MTX_SPIN);
DROP_GIANT_NOSWITCH();
mi_switch();
@@ -1414,13 +1421,15 @@
/*
* Put the argument process into the stopped state and notify the parent
* via wakeup. Signals are handled elsewhere. The process must not be
- * on the run queue.
+ * on the run queue. Must be called with at least a shared hold of the
+ * proctree lock.
*/
void
stop(p)
register struct proc *p;
{
+ PROCTREE_ASSERT(PT_SHARED);
mtx_enter(&sched_lock, MTX_SPIN);
p->p_stat = SSTOP;
p->p_flag &= ~P_WAITED;
Index: kern/sys_process.c
===================================================================
RCS file: /home/ncvs/src/sys/kern/sys_process.c,v
retrieving revision 1.55
diff -u -r1.55 sys_process.c
--- kern/sys_process.c 2000/12/12 07:25:53 1.55
+++ kern/sys_process.c 2000/12/18 01:24:58
@@ -276,8 +276,12 @@
return EPERM;
/* not being traced by YOU */
- if (p->p_pptr != curp)
+ PROCTREE_LOCK(PT_SHARED);
+ if (p->p_pptr != curp) {
+ PROCTREE_LOCK(PT_RELEASE);
return EBUSY;
+ }
+ PROCTREE_LOCK(PT_RELEASE);
/* not currently stopped */
mtx_enter(&sched_lock, MTX_SPIN);
@@ -311,15 +315,19 @@
case PT_TRACE_ME:
/* set my trace flag and "owner" so it can read/write me */
p->p_flag |= P_TRACED;
+ PROCTREE_LOCK(PT_SHARED);
p->p_oppid = p->p_pptr->p_pid;
+ PROCTREE_LOCK(PT_RELEASE);
return 0;
case PT_ATTACH:
/* security check done above */
p->p_flag |= P_TRACED;
+ PROCTREE_LOCK(PT_EXCLUSIVE);
p->p_oppid = p->p_pptr->p_pid;
if (p->p_pptr != curp)
proc_reparent(p, curp);
+ PROCTREE_LOCK(PT_RELEASE);
uap->data = SIGSTOP;
goto sendsig; /* in PT_CONTINUE below */
@@ -350,12 +358,14 @@
if (uap->req == PT_DETACH) {
/* reset process parent */
+ PROCTREE_LOCK(PT_EXCLUSIVE);
if (p->p_oppid != p->p_pptr->p_pid) {
struct proc *pp;
pp = pfind(p->p_oppid);
proc_reparent(p, pp ? pp : initproc);
}
+ PROCTREE_LOCK(PT_RELEASE);
p->p_flag &= ~(P_TRACED | P_WAITED);
p->p_oppid = 0;
Index: miscfs/procfs/procfs_ctl.c
===================================================================
RCS file: /home/ncvs/src/sys/miscfs/procfs/procfs_ctl.c,v
retrieving revision 1.22
diff -u -r1.22 procfs_ctl.c
--- miscfs/procfs/procfs_ctl.c 2000/12/13 04:28:24 1.22
+++ miscfs/procfs/procfs_ctl.c 2000/12/19 20:57:43
@@ -144,10 +144,12 @@
p->p_flag |= P_TRACED;
faultin(p);
p->p_xstat = 0; /* XXX ? */
+ PROCTREE_LOCK(PT_EXCLUSIVE);
if (p->p_pptr != curp) {
p->p_oppid = p->p_pptr->p_pid;
proc_reparent(p, curp);
}
+ PROCTREE_LOCK(PT_RELEASE);
psignal(p, SIGSTOP);
return (0);
}
@@ -164,12 +166,15 @@
break;
default:
+ PROCTREE_LOCK(PT_SHARED);
mtx_enter(&sched_lock, MTX_SPIN);
if (!TRACE_WAIT_P(curp, p)) {
mtx_exit(&sched_lock, MTX_SPIN);
+ PROCTREE_LOCK(PT_RELEASE);
return (EBUSY);
}
mtx_exit(&sched_lock, MTX_SPIN);
+ PROCTREE_LOCK(PT_RELEASE);
}
@@ -204,6 +209,7 @@
SIGDELSET(p->p_siglist, SIGTRAP);
/* give process back to original parent */
+ PROCTREE_LOCK(PT_EXCLUSIVE);
if (p->p_oppid != p->p_pptr->p_pid) {
struct proc *pp;
@@ -211,6 +217,7 @@
if (pp)
proc_reparent(p, pp);
}
+ PROCTREE_LOCK(PT_RELEASE);
p->p_oppid = 0;
p->p_flag &= ~P_WAITED; /* XXX ? */
@@ -244,19 +251,23 @@
case PROCFS_CTL_WAIT:
error = 0;
if (p->p_flag & P_TRACED) {
+ PROCTREE_LOCK(PT_SHARED);
mtx_enter(&sched_lock, MTX_SPIN);
while (error == 0 &&
(p->p_stat != SSTOP) &&
(p->p_flag & P_TRACED) &&
(p->p_pptr == curp)) {
mtx_exit(&sched_lock, MTX_SPIN);
+ PROCTREE_LOCK(PT_RELEASE);
error = tsleep((caddr_t) p,
PWAIT|PCATCH, "procfsx", 0);
+ PROCTREE_LOCK(PT_SHARED);
mtx_enter(&sched_lock, MTX_SPIN);
}
if (error == 0 && !TRACE_WAIT_P(curp, p))
error = EBUSY;
mtx_exit(&sched_lock, MTX_SPIN);
+ PROCTREE_LOCK(PT_RELEASE);
} else {
mtx_enter(&sched_lock, MTX_SPIN);
while (error == 0 && p->p_stat != SSTOP) {
@@ -317,6 +328,7 @@
} else {
nm = vfs_findname(signames, msg, xlen);
if (nm) {
+ PROCTREE_LOCK(PT_SHARED);
mtx_enter(&sched_lock, MTX_SPIN);
if (TRACE_WAIT_P(curp, p)) {
p->p_xstat = nm->nm_val;
@@ -325,8 +337,10 @@
#endif
setrunnable(p);
mtx_exit(&sched_lock, MTX_SPIN);
+ PROCTREE_LOCK(PT_RELEASE);
} else {
mtx_exit(&sched_lock, MTX_SPIN);
+ PROCTREE_LOCK(PT_RELEASE);
psignal(p, nm->nm_val);
}
error = 0;
Index: miscfs/procfs/procfs_status.c
===================================================================
RCS file: /home/ncvs/src/sys/miscfs/procfs/procfs_status.c,v
retrieving revision 1.23
diff -u -r1.23 procfs_status.c
--- miscfs/procfs/procfs_status.c 2000/11/08 21:53:05 1.23
+++ miscfs/procfs/procfs_status.c 2000/12/18 01:30:10
@@ -78,7 +78,9 @@
return (EOPNOTSUPP);
pid = p->p_pid;
+ PROCTREE_LOCK(PT_SHARED);
ppid = p->p_pptr ? p->p_pptr->p_pid : 0;
+ PROCTREE_LOCK(PT_RELEASE);
pgid = p->p_pgrp->pg_id;
sess = p->p_pgrp->pg_session;
sid = sess->s_leader ? sess->s_leader->p_pid : 0;
Index: sys/proc.h
===================================================================
RCS file: /home/ncvs/src/sys/sys/proc.h,v
retrieving revision 1.136
diff -u -r1.136 proc.h
--- sys/proc.h 2000/12/15 00:10:32 1.136
+++ sys/proc.h 2000/12/18 05:46:41
@@ -415,6 +415,17 @@
#define AP_EXCLUSIVE LK_EXCLUSIVE
#define AP_RELEASE LK_RELEASE
+/* Lock and unlock the proc child and sibling lists. */
+#define PROCTREE_LOCK(how) \
+ lockmgr(&proctree_lock, (how), NULL, CURPROC)
+
+#define PROCTREE_ASSERT(what) \
+ LOCKMGR_ASSERT(&proctree_lock, (what), CURPROC)
+
+#define PT_SHARED LK_SHARED
+#define PT_EXCLUSIVE LK_EXCLUSIVE
+#define PT_RELEASE LK_RELEASE
+
/* Hold process U-area in memory, normally for ptrace/procfs work. */
#define PHOLD(p) do { \
PROC_LOCK(p); \
@@ -439,6 +450,7 @@
extern u_long pgrphash;
extern struct lock allproc_lock;
+extern struct lock proctree_lock;
extern struct proc proc0; /* Process slot for swapper. */
extern int hogticks; /* Limit on kernel cpu hogs. */
extern int nprocs, maxproc; /* Current and max number of procs. */
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