On Wed, Sep 16, 2020 at 01:40:43PM -0700, Joe Perches wrote:
> 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@xxxxxxxxxxx>
> ---
> 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]);
> }
That is NOT one-value-per-file, which is required for sysfs files. This
should be 3 different sysfs files.
Ugh.
But that's separate from this series, thanks for redoing this. I'll
take a look at it on Monday...
thanks,
greg k-h
