svn commit: r222839 - in stable/8/sys: compat/linprocfs
fs/nfsclient kern vm
John Baldwin
jhb at FreeBSD.org
Tue Jun 7 21:48:37 UTC 2011
Author: jhb
Date: Tue Jun 7 21:48:36 2011
New Revision: 222839
URL: http://svn.freebsd.org/changeset/base/222839
Log:
MFC 219968:
Fix some locking nits with the p_state field of struct proc:
- Hold the proc lock while changing the state from PRS_NEW to PRS_NORMAL
in fork to honor the locking requirements. While here, expand the scope
of the PROC_LOCK() on the new process (p2) to avoid some LORs. Previously
the code was locking the new child process (p2) after it had locked the
parent process (p1). However, when locking two processes, the safe order
is to lock the child first, then the parent.
- Fix various places that were checking p_state against PRS_NEW without
having the process locked to use PROC_LOCK(). Every place was already
locking the process, just after the PRS_NEW check.
- Remove or reduce the use of PROC_SLOCK() for places that were checking
p_state against PRS_NEW. The PROC_LOCK() alone is sufficient for reading
the current state.
Modified:
stable/8/sys/compat/linprocfs/linprocfs.c
stable/8/sys/fs/nfsclient/nfs_clport.c
stable/8/sys/kern/kern_descrip.c
stable/8/sys/kern/kern_fork.c
stable/8/sys/kern/kern_proc.c
stable/8/sys/kern/kern_resource.c
stable/8/sys/vm/vm_meter.c
stable/8/sys/vm/vm_pageout.c
Directory Properties:
stable/8/sys/ (props changed)
stable/8/sys/amd64/include/xen/ (props changed)
stable/8/sys/cddl/contrib/opensolaris/ (props changed)
stable/8/sys/contrib/dev/acpica/ (props changed)
stable/8/sys/contrib/pf/ (props changed)
Modified: stable/8/sys/compat/linprocfs/linprocfs.c
==============================================================================
--- stable/8/sys/compat/linprocfs/linprocfs.c Tue Jun 7 21:16:02 2011 (r222838)
+++ stable/8/sys/compat/linprocfs/linprocfs.c Tue Jun 7 21:48:36 2011 (r222839)
@@ -739,7 +739,6 @@ linprocfs_doprocstatus(PFS_FILL_ARGS)
if (P_SHOULDSTOP(p)) {
state = "T (stopped)";
} else {
- PROC_SLOCK(p);
switch(p->p_state) {
case PRS_NEW:
state = "I (idle)";
@@ -769,7 +768,6 @@ linprocfs_doprocstatus(PFS_FILL_ARGS)
state = "? (unknown)";
break;
}
- PROC_SUNLOCK(p);
}
fill_kinfo_proc(p, &kp);
Modified: stable/8/sys/fs/nfsclient/nfs_clport.c
==============================================================================
--- stable/8/sys/fs/nfsclient/nfs_clport.c Tue Jun 7 21:16:02 2011 (r222838)
+++ stable/8/sys/fs/nfsclient/nfs_clport.c Tue Jun 7 21:48:36 2011 (r222839)
@@ -1126,11 +1126,11 @@ pfind_locked(pid_t pid)
LIST_FOREACH(p, PIDHASH(pid), p_hash)
if (p->p_pid == pid) {
+ PROC_LOCK(p);
if (p->p_state == PRS_NEW) {
+ PROC_UNLOCK(p);
p = NULL;
- break;
}
- PROC_LOCK(p);
break;
}
return (p);
Modified: stable/8/sys/kern/kern_descrip.c
==============================================================================
--- stable/8/sys/kern/kern_descrip.c Tue Jun 7 21:16:02 2011 (r222838)
+++ stable/8/sys/kern/kern_descrip.c Tue Jun 7 21:48:36 2011 (r222839)
@@ -2643,9 +2643,11 @@ sysctl_kern_file(SYSCTL_HANDLER_ARGS)
xf.xf_size = sizeof(xf);
sx_slock(&allproc_lock);
FOREACH_PROC_IN_SYSTEM(p) {
- if (p->p_state == PRS_NEW)
- continue;
PROC_LOCK(p);
+ if (p->p_state == PRS_NEW) {
+ PROC_UNLOCK(p);
+ continue;
+ }
if (p_cansee(req->td, p) != 0) {
PROC_UNLOCK(p);
continue;
Modified: stable/8/sys/kern/kern_fork.c
==============================================================================
--- stable/8/sys/kern/kern_fork.c Tue Jun 7 21:16:02 2011 (r222838)
+++ stable/8/sys/kern/kern_fork.c Tue Jun 7 21:48:36 2011 (r222839)
@@ -722,10 +722,13 @@ again:
/*
* Set the child start time and mark the process as being complete.
*/
+ PROC_LOCK(p2);
+ PROC_LOCK(p1);
microuptime(&p2->p_stats->p_start);
PROC_SLOCK(p2);
p2->p_state = PRS_NORMAL;
PROC_SUNLOCK(p2);
+
#ifdef KDTRACE_HOOKS
/*
* Tell the DTrace fasttrap provider about the new process
@@ -733,16 +736,9 @@ again:
* p_state is PRS_NORMAL since the fasttrap module will use pfind()
* later on.
*/
- if (dtrace_fasttrap_fork) {
- PROC_LOCK(p1);
- PROC_LOCK(p2);
+ if (dtrace_fasttrap_fork)
dtrace_fasttrap_fork(p1, p2);
- PROC_UNLOCK(p2);
- PROC_UNLOCK(p1);
- }
#endif
-
- PROC_LOCK(p1);
if ((p1->p_flag & (P_TRACED | P_FOLLOWFORK)) == (P_TRACED |
P_FOLLOWFORK)) {
/*
@@ -754,12 +750,11 @@ again:
*/
td->td_dbgflags |= TDB_FORK;
td->td_dbg_forked = p2->p_pid;
- PROC_LOCK(p2);
td2->td_dbgflags |= TDB_STOPATFORK;
_PHOLD(p2);
p2_held = 1;
- PROC_UNLOCK(p2);
}
+ PROC_UNLOCK(p2);
if ((flags & RFSTOPPED) == 0) {
/*
* If RFSTOPPED not requested, make child runnable and
Modified: stable/8/sys/kern/kern_proc.c
==============================================================================
--- stable/8/sys/kern/kern_proc.c Tue Jun 7 21:16:02 2011 (r222838)
+++ stable/8/sys/kern/kern_proc.c Tue Jun 7 21:48:36 2011 (r222839)
@@ -290,11 +290,11 @@ pfind(pid)
sx_slock(&allproc_lock);
LIST_FOREACH(p, PIDHASH(pid), p_hash)
if (p->p_pid == pid) {
+ PROC_LOCK(p);
if (p->p_state == PRS_NEW) {
+ PROC_UNLOCK(p);
p = NULL;
- break;
}
- PROC_LOCK(p);
break;
}
sx_sunlock(&allproc_lock);
@@ -750,7 +750,6 @@ fill_kinfo_proc_only(struct proc *p, str
kp->ki_sigcatch = ps->ps_sigcatch;
mtx_unlock(&ps->ps_mtx);
}
- PROC_SLOCK(p);
if (p->p_state != PRS_NEW &&
p->p_state != PRS_ZOMBIE &&
p->p_vmspace != NULL) {
@@ -776,6 +775,7 @@ fill_kinfo_proc_only(struct proc *p, str
kp->ki_swtime = (ticks - p->p_swtick) / hz;
kp->ki_pid = p->p_pid;
kp->ki_nice = p->p_nice;
+ PROC_SLOCK(p);
rufetch(p, &kp->ki_rusage);
kp->ki_runtime = cputick2usec(p->p_rux.rux_runtime);
PROC_SUNLOCK(p);
@@ -1208,13 +1208,11 @@ sysctl_kern_proc(SYSCTL_HANDLER_ARGS)
/*
* Skip embryonic processes.
*/
- PROC_SLOCK(p);
+ PROC_LOCK(p);
if (p->p_state == PRS_NEW) {
- PROC_SUNLOCK(p);
+ PROC_UNLOCK(p);
continue;
}
- PROC_SUNLOCK(p);
- PROC_LOCK(p);
KASSERT(p->p_ucred != NULL,
("process credential is NULL for non-NEW proc"));
/*
Modified: stable/8/sys/kern/kern_resource.c
==============================================================================
--- stable/8/sys/kern/kern_resource.c Tue Jun 7 21:16:02 2011 (r222838)
+++ stable/8/sys/kern/kern_resource.c Tue Jun 7 21:48:36 2011 (r222839)
@@ -142,11 +142,9 @@ getpriority(td, uap)
uap->who = td->td_ucred->cr_uid;
sx_slock(&allproc_lock);
FOREACH_PROC_IN_SYSTEM(p) {
- /* Do not bother to check PRS_NEW processes */
- if (p->p_state == PRS_NEW)
- continue;
PROC_LOCK(p);
- if (p_cansee(td, p) == 0 &&
+ if (p->p_state == PRS_NORMAL &&
+ p_cansee(td, p) == 0 &&
p->p_ucred->cr_uid == uap->who) {
if (p->p_nice < low)
low = p->p_nice;
Modified: stable/8/sys/vm/vm_meter.c
==============================================================================
--- stable/8/sys/vm/vm_meter.c Tue Jun 7 21:16:02 2011 (r222838)
+++ stable/8/sys/vm/vm_meter.c Tue Jun 7 21:48:36 2011 (r222839)
@@ -132,15 +132,12 @@ vmtotal(SYSCTL_HANDLER_ARGS)
if (p->p_flag & P_SYSTEM)
continue;
PROC_LOCK(p);
- PROC_SLOCK(p);
switch (p->p_state) {
case PRS_NEW:
- PROC_SUNLOCK(p);
PROC_UNLOCK(p);
continue;
break;
default:
- PROC_SUNLOCK(p);
FOREACH_THREAD_IN_PROC(p, td) {
thread_lock(td);
switch (td->td_state) {
Modified: stable/8/sys/vm/vm_pageout.c
==============================================================================
--- stable/8/sys/vm/vm_pageout.c Tue Jun 7 21:16:02 2011 (r222838)
+++ stable/8/sys/vm/vm_pageout.c Tue Jun 7 21:48:36 2011 (r222839)
@@ -1212,7 +1212,8 @@ vm_pageout_oom(int shortage)
/*
* If this is a system, protected or killed process, skip it.
*/
- if ((p->p_flag & (P_INEXEC | P_PROTECTED | P_SYSTEM)) ||
+ if (p->p_state != PRS_NORMAL ||
+ (p->p_flag & (P_INEXEC | P_PROTECTED | P_SYSTEM)) ||
(p->p_pid == 1) || P_KILLED(p) ||
((p->p_pid < 48) && (swap_pager_avail != 0))) {
PROC_UNLOCK(p);
@@ -1573,7 +1574,8 @@ vm_daemon()
* looked at this process, skip it.
*/
PROC_LOCK(p);
- if (p->p_flag & (P_INEXEC | P_SYSTEM | P_WEXIT)) {
+ if (p->p_state != PRS_NORMAL ||
+ p->p_flag & (P_INEXEC | P_SYSTEM | P_WEXIT)) {
PROC_UNLOCK(p);
continue;
}
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