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-rw-r--r--mm/hugetlb.c26
1 files changed, 20 insertions, 6 deletions
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 2c22ea7a2013..b469d099dc5f 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -2921,6 +2921,22 @@ static unsigned int cpuset_mems_nr(unsigned int *array)
}
#ifdef CONFIG_SYSCTL
+static int proc_hugetlb_doulongvec_minmax(struct ctl_table *table, int write,
+ void *buffer, size_t *length,
+ loff_t *ppos, unsigned long *out)
+{
+ struct ctl_table dup_table;
+
+ /*
+ * In order to avoid races with __do_proc_doulongvec_minmax(), we
+ * can duplicate the @table and alter the duplicate of it.
+ */
+ dup_table = *table;
+ dup_table.data = out;
+
+ return proc_doulongvec_minmax(&dup_table, write, buffer, length, ppos);
+}
+
static int hugetlb_sysctl_handler_common(bool obey_mempolicy,
struct ctl_table *table, int write,
void __user *buffer, size_t *length, loff_t *ppos)
@@ -2932,9 +2948,8 @@ static int hugetlb_sysctl_handler_common(bool obey_mempolicy,
if (!hugepages_supported())
return -EOPNOTSUPP;
- table->data = &tmp;
- table->maxlen = sizeof(unsigned long);
- ret = proc_doulongvec_minmax(table, write, buffer, length, ppos);
+ ret = proc_hugetlb_doulongvec_minmax(table, write, buffer, length, ppos,
+ &tmp);
if (ret)
goto out;
@@ -2978,9 +2993,8 @@ int hugetlb_overcommit_handler(struct ctl_table *table, int write,
if (write && hstate_is_gigantic(h))
return -EINVAL;
- table->data = &tmp;
- table->maxlen = sizeof(unsigned long);
- ret = proc_doulongvec_minmax(table, write, buffer, length, ppos);
+ ret = proc_hugetlb_doulongvec_minmax(table, write, buffer, length, ppos,
+ &tmp);
if (ret)
goto out;