Wire the sysctl output buffer before grabbing any locks to prevent

SYSCTL_OUT() from blocking while locks are held.  This should
only be done when it would be inconvenient to make a temporary copy of
the data and defer calling SYSCTL_OUT() until after the locks are
released.

9 files changed, 15 insertions, 0 deletions

diff --git a/sys/kern/kern_descrip.c b/sys/kern/kern_descrip.c
index 43a7e44..06aca87 100644
--- a/sys/kern/kern_descrip.c
+++ b/sys/kern/kern_descrip.c
@@ -2043,6 +2043,7 @@ sysctl_kern_file(SYSCTL_HANDLER_ARGS)
 	int error;
 	struct file *fp;
 
+	sysctl_wire_old_buffer(req, 0);
 	sx_slock(&filelist_lock);
 	if (!req->oldptr) {
 		/*
diff --git a/sys/kern/kern_fork.c b/sys/kern/kern_fork.c
index 53b3eed..18644df 100644
--- a/sys/kern/kern_fork.c
+++ b/sys/kern/kern_fork.c
@@ -193,6 +193,7 @@ sysctl_kern_randompid(SYSCTL_HANDLER_ARGS)
 {
 	int error, pid;
 
+	sysctl_wire_old_buffer(req, sizeof(int));
 	sx_xlock(&allproc_lock);
 	pid = randompid;
 	error = sysctl_handle_int(oidp, &pid, 0, req);
diff --git a/sys/kern/kern_proc.c b/sys/kern/kern_proc.c
index 3547196..6cf9fe9 100644
--- a/sys/kern/kern_proc.c
+++ b/sys/kern/kern_proc.c
@@ -1023,6 +1023,7 @@ sysctl_kern_proc(SYSCTL_HANDLER_ARGS)
 		if (error)
 			return (error);
 	}
+	sysctl_wire_old_buffer(req, 0);
 	sx_slock(&allproc_lock);
 	for (doingzomb=0 ; doingzomb < 2 ; doingzomb++) {
 		if (!doingzomb)
diff --git a/sys/kern/vfs_subr.c b/sys/kern/vfs_subr.c
index 4d87718..1684782 100644
--- a/sys/kern/vfs_subr.c
+++ b/sys/kern/vfs_subr.c
@@ -2652,6 +2652,7 @@ sysctl_vnode(SYSCTL_HANDLER_ARGS)
 		return (SYSCTL_OUT(req, 0,
 			(numvnodes + KINFO_VNODESLOP) * (VPTRSZ + VNODESZ)));
 
+	sysctl_wire_old_buffer(req, 0);
 	mtx_lock(&mountlist_mtx);
 	for (mp = TAILQ_FIRST(&mountlist); mp != NULL; mp = nmp) {
 		if (vfs_busy(mp, LK_NOWAIT, &mountlist_mtx, td)) {
diff --git a/sys/netinet/tcp_subr.c b/sys/netinet/tcp_subr.c
index c2799d5..0c4b385 100644
--- a/sys/netinet/tcp_subr.c
+++ b/sys/netinet/tcp_subr.c
@@ -841,6 +841,9 @@ tcp_pcblist(SYSCTL_HANDLER_ARGS)
 	INP_INFO_RUNLOCK(&tcbinfo);
 	splx(s);
 
+	sysctl_wire_old_buffer(req, 2 * (sizeof xig)
+		+ n * sizeof(struct xtcpcb));
+
 	xig.xig_len = sizeof xig;
 	xig.xig_count = n;
 	xig.xig_gen = gencnt;
diff --git a/sys/netinet/tcp_timewait.c b/sys/netinet/tcp_timewait.c
index c2799d5..0c4b385 100644
--- a/sys/netinet/tcp_timewait.c
+++ b/sys/netinet/tcp_timewait.c
@@ -841,6 +841,9 @@ tcp_pcblist(SYSCTL_HANDLER_ARGS)
 	INP_INFO_RUNLOCK(&tcbinfo);
 	splx(s);
 
+	sysctl_wire_old_buffer(req, 2 * (sizeof xig)
+		+ n * sizeof(struct xtcpcb));
+
 	xig.xig_len = sizeof xig;
 	xig.xig_count = n;
 	xig.xig_gen = gencnt;
diff --git a/sys/netinet/udp_usrreq.c b/sys/netinet/udp_usrreq.c
index 56bb1e1..b93e99e 100644
--- a/sys/netinet/udp_usrreq.c
+++ b/sys/netinet/udp_usrreq.c
@@ -598,6 +598,9 @@ udp_pcblist(SYSCTL_HANDLER_ARGS)
 	n = udbinfo.ipi_count;
 	splx(s);
 
+	sysctl_wire_old_buffer(req, 2 * (sizeof xig)
+		+ n * sizeof(struct xinpcb));
+
 	xig.xig_len = sizeof xig;
 	xig.xig_count = n;
 	xig.xig_gen = gencnt;
diff --git a/sys/netncp/ncp_conn.c b/sys/netncp/ncp_conn.c
index 85f4163..14b8d7b 100644
--- a/sys/netncp/ncp_conn.c
+++ b/sys/netncp/ncp_conn.c
@@ -633,6 +633,7 @@ ncp_sysctl_connstat(SYSCTL_HANDLER_ARGS) {
 /*	struct ucred *cred = req->p->p_ucred;*/
 
 	error = 0;
+	sysctl_wire_old_buffer(req, 0);
 	ncp_conn_locklist(LK_SHARED, req->p);
 	error = SYSCTL_OUT(req, &ncp_conn_cnt, sizeof(ncp_conn_cnt));
 	SLIST_FOREACH(ncp, &conn_list, nc_next) {
diff --git a/sys/netsmb/smb_conn.c b/sys/netsmb/smb_conn.c
index 657c469..9c52571 100644
--- a/sys/netsmb/smb_conn.c
+++ b/sys/netsmb/smb_conn.c
@@ -834,6 +834,7 @@ smb_sysctl_treedump(SYSCTL_HANDLER_ARGS)
 	int error, itype;
 
 	smb_makescred(&scred, td, td->td_ucred);
+	sysctl_wire_old_buffer(req, 0);
 	error = smb_sm_lockvclist(LK_SHARED, td);
 	if (error)
 		return error;