mm: and drivers core: Convert hugetlb_report_node_meminfo to sysfs_emit

Convert the unbound sprintf in hugetlb_report_node_meminfo to use
sysfs_emit_at so that no possible overrun of a PAGE_SIZE buf can occur.

Signed-off-by: Joe Perches <joe@perches.com>
Acked-by: Mike Kravetz <mike.kravetz@oracle.com>
Link: https://lore.kernel.org/r/894b351b82da6013cde7f36ff4b5493cd0ec30d0.1600285923.git.joe@perches.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/base/node.c b/drivers/base/node.c
index 96d820f..6366f94 100644 (file)
--- a/drivers/base/node.c
+++ b/drivers/base/node.c
@@ -473,7 +473,7 @@ static ssize_t node_read_meminfo(struct device *dev,
                                    HPAGE_PMD_NR)
 #endif
                            );
-       len += hugetlb_report_node_meminfo(nid, buf + len);
+       len += hugetlb_report_node_meminfo(buf, len, nid);
        return len;
 }
 

diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index d5cc5f8..ebca2ef 100644 (file)
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -129,7 +129,7 @@ void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct *vma,
                                unsigned long start, unsigned long end,
                                struct page *ref_page);
 void hugetlb_report_meminfo(struct seq_file *);
-int hugetlb_report_node_meminfo(int, char *);
+int hugetlb_report_node_meminfo(char *buf, int len, int nid);
 void hugetlb_show_meminfo(void);
 unsigned long hugetlb_total_pages(void);
 vm_fault_t hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
@@ -245,7 +245,7 @@ static inline void hugetlb_report_meminfo(struct seq_file *m)
 {
 }
 
-static inline int hugetlb_report_node_meminfo(int nid, char *buf)
+static inline int hugetlb_report_node_meminfo(char *buf, int len, int nid)
 {
        return 0;
 }

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 67fc638..365ef52 100644 (file)
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -3582,18 +3582,20 @@ void hugetlb_report_meminfo(struct seq_file *m)
        seq_printf(m, "Hugetlb:        %8lu kB\n", total / 1024);
 }
 
-int hugetlb_report_node_meminfo(int nid, char *buf)
+int hugetlb_report_node_meminfo(char *buf, int len, int nid)
 {
        struct hstate *h = &default_hstate;
+
        if (!hugepages_supported())
                return 0;
-       return sprintf(buf,
-               "Node %d HugePages_Total: %5u\n"
-               "Node %d HugePages_Free:  %5u\n"
-               "Node %d HugePages_Surp:  %5u\n",
-               nid, h->nr_huge_pages_node[nid],
-               nid, h->free_huge_pages_node[nid],
-               nid, h->surplus_huge_pages_node[nid]);
+
+       return sysfs_emit_at(buf, len,
+                            "Node %d HugePages_Total: %5u\n"
+                            "Node %d HugePages_Free:  %5u\n"
+                            "Node %d HugePages_Surp:  %5u\n",
+                            nid, h->nr_huge_pages_node[nid],
+                            nid, h->free_huge_pages_node[nid],
+                            nid, h->surplus_huge_pages_node[nid]);
 }
 
 void hugetlb_show_meminfo(void)