svn commit: r366675 - stable/12/sys/kern

[Alexander Motin]

Author: mav
Date: Tue Oct 13 17:50:01 2020
New Revision: 366675
URL: https://svnweb.freebsd.org/changeset/base/366675

Log:
  MFC r355083 (by rlibby): sysctl: wire old buf before output with sysctl lock
  
  Several sysctl sysctls output to a user buffer while holding a
  non-sleepable lock that protects the sysctl topology.  They need to wire
  the output buffer, or else they may try to sleep on a page fault.

Modified:
  stable/12/sys/kern/kern_sysctl.c
Directory Properties:
  stable/12/   (props changed)

Modified: stable/12/sys/kern/kern_sysctl.c
==============================================================================
--- stable/12/sys/kern/kern_sysctl.c	Tue Oct 13 17:30:34 2020	(r366674)
+++ stable/12/sys/kern/kern_sysctl.c	Tue Oct 13 17:50:01 2020	(r366675)
@@ -1022,12 +1022,16 @@ sysctl_sysctl_name(SYSCTL_HANDLER_ARGS)
 {
 	int *name = (int *) arg1;
 	u_int namelen = arg2;
-	int error = 0;
+	int error;
 	struct sysctl_oid *oid;
 	struct sysctl_oid_list *lsp = &sysctl__children, *lsp2;
 	struct rm_priotracker tracker;
 	char buf[10];
 
+	error = sysctl_wire_old_buffer(req, 0);
+	if (error)
+		return (error);
+
 	SYSCTL_RLOCK(&tracker);
 	while (namelen) {
 		if (!lsp) {
@@ -1264,6 +1268,10 @@ sysctl_sysctl_oidfmt(SYSCTL_HANDLER_ARGS)
 	struct rm_priotracker tracker;
 	int error;
 
+	error = sysctl_wire_old_buffer(req, 0);
+	if (error)
+		return (error);
+
 	SYSCTL_RLOCK(&tracker);
 	error = sysctl_find_oid(arg1, arg2, &oid, NULL, req);
 	if (error)
@@ -1293,6 +1301,10 @@ sysctl_sysctl_oiddescr(SYSCTL_HANDLER_ARGS)
 	struct rm_priotracker tracker;
 	int error;
 
+	error = sysctl_wire_old_buffer(req, 0);
+	if (error)
+		return (error);
+
 	SYSCTL_RLOCK(&tracker);
 	error = sysctl_find_oid(arg1, arg2, &oid, NULL, req);
 	if (error)
@@ -1317,6 +1329,10 @@ sysctl_sysctl_oidlabel(SYSCTL_HANDLER_ARGS)
 	struct sysctl_oid *oid;
 	struct rm_priotracker tracker;
 	int error;
+
+	error = sysctl_wire_old_buffer(req, 0);
+	if (error)
+		return (error);
 
 	SYSCTL_RLOCK(&tracker);
 	error = sysctl_find_oid(arg1, arg2, &oid, NULL, req);