Merge tag 'sysctl-6.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux

Pull sysctl update from Luis Chamberlain:
 "Just one fix which just came in.

  Sadly the eager beavers willing to help with the sysctl moves have
  slowed"

* tag 'sysctl-6.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux:
  sysctl: fix proc_dobool() usability

Author: torvalds

fs/lockd/svc.c

@@ -496,7 +496,7 @@ static struct ctl_table nlm_sysctls[] = {
 	{
 		.procname	= "nsm_use_hostnames",
 		.data		= &nsm_use_hostnames,
-		.maxlen		= sizeof(int),
+		.maxlen		= sizeof(bool),
 		.mode		= 0644,
 		.proc_handler	= proc_dobool,
 	},

fs/proc/proc_sysctl.c

@@ -1124,6 +1124,11 @@ static int sysctl_check_table_array(const char *path, struct ctl_table *table)
 			err |= sysctl_err(path, table, "array not allowed");
 	}
 
+	if (table->proc_handler == proc_dobool) {
+		if (table->maxlen != sizeof(bool))
+			err |= sysctl_err(path, table, "array not allowed");
+	}
+
 	return err;
 }
 
@@ -1136,6 +1141,7 @@ static int sysctl_check_table(const char *path, struct ctl_table *table)
 			err |= sysctl_err(path, entry, "Not a file");
 
 		if ((entry->proc_handler == proc_dostring) ||
+		    (entry->proc_handler == proc_dobool) ||
 		    (entry->proc_handler == proc_dointvec) ||
 		    (entry->proc_handler == proc_douintvec) ||
 		    (entry->proc_handler == proc_douintvec_minmax) ||

kernel/sysctl.c

@@ -425,21 +425,6 @@ static void proc_put_char(void **buf, size_t *size, char c)
 	}
 }
 
-static int do_proc_dobool_conv(bool *negp, unsigned long *lvalp,
-				int *valp,
-				int write, void *data)
-{
-	if (write) {
-		*(bool *)valp = *lvalp;
-	} else {
-		int val = *(bool *)valp;
-
-		*lvalp = (unsigned long)val;
-		*negp = false;
-	}
-	return 0;
-}
-
 static int do_proc_dointvec_conv(bool *negp, unsigned long *lvalp,
 				 int *valp,
 				 int write, void *data)
@@ -710,16 +695,36 @@ int do_proc_douintvec(struct ctl_table *table, int write,
  * @lenp: the size of the user buffer
  * @ppos: file position
  *
- * Reads/writes up to table->maxlen/sizeof(unsigned int) integer
- * values from/to the user buffer, treated as an ASCII string.
+ * Reads/writes one integer value from/to the user buffer,
+ * treated as an ASCII string.
+ *
+ * table->data must point to a bool variable and table->maxlen must
+ * be sizeof(bool).
  *
  * Returns 0 on success.
  */
 int proc_dobool(struct ctl_table *table, int write, void *buffer,
 		size_t *lenp, loff_t *ppos)
 {
-	return do_proc_dointvec(table, write, buffer, lenp, ppos,
-				do_proc_dobool_conv, NULL);
+	struct ctl_table tmp;
+	bool *data = table->data;
+	int res, val;
+
+	/* Do not support arrays yet. */
+	if (table->maxlen != sizeof(bool))
+		return -EINVAL;
+
+	tmp = *table;
+	tmp.maxlen = sizeof(val);
+	tmp.data = &val;
+
+	val = READ_ONCE(*data);
+	res = proc_dointvec(&tmp, write, buffer, lenp, ppos);
+	if (res)
+		return res;
+	if (write)
+		WRITE_ONCE(*data, val);
+	return 0;
 }
 
 /**

mm/hugetlb_vmemmap.c

@@ -581,7 +581,7 @@ static struct ctl_table hugetlb_vmemmap_sysctls[] = {
 	{
 		.procname	= "hugetlb_optimize_vmemmap",
 		.data		= &vmemmap_optimize_enabled,
-		.maxlen		= sizeof(int),
+		.maxlen		= sizeof(vmemmap_optimize_enabled),
 		.mode		= 0644,
 		.proc_handler	= proc_dobool,
 	},