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Subject[PATCH V3 6/8] mm: and drivers core: Convert hugetlb_report_node_meminfo to sysfs_emit
Date
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>
---
drivers/base/node.c | 2 +-
include/linux/hugetlb.h | 4 ++--
mm/hugetlb.c | 18 ++++++++++--------
3 files changed, 13 insertions(+), 11 deletions(-)

diff --git a/drivers/base/node.c b/drivers/base/node.c
index b33526a9fcfc..dafe03e82e7c 100644
--- 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 d5cc5f802dd4..ebca2ef02212 100644
--- 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 61469fd3ad92..fe76f8fd5a73 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -3571,18 +3571,20 @@ 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)
--
2.26.0
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