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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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