[PATCH] hugetlbfs: check dir in trace_hugetlbfs_alloc_inode

[zhuxiaohui]

From: Xiaohui Zhu <zhuxiaohui....@bytedance.com>

Anonymous huge page has no corresponding directory inode,
which cause a null pointer crash when access dir with the stack

  trace_hugetlbfs_alloc_inode
  hugetlbfs_get_inode
  hugetlb_file_setup
  ksys_mmap_pgoff

Signed-off-by: Xiaohui Zhu <zhuxiaohui....@bytedance.com>
---
 include/trace/events/hugetlbfs.h | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/include/trace/events/hugetlbfs.h b/include/trace/events/hugetlbfs.h
index 8331c904a9ba..5daa52053edc 100644
--- a/include/trace/events/hugetlbfs.h
+++ b/include/trace/events/hugetlbfs.h
@@ -23,7 +23,9 @@ TRACE_EVENT(hugetlbfs_alloc_inode,
        TP_fast_assign(
                __entry->dev            = inode->i_sb->s_dev;
                __entry->ino            = inode->i_ino;
-               __entry->dir            = dir->i_ino;
+               __entry->dir            = 0;
+               if (dir)
+                       __entry->dir    = dir->i_ino;
                __entry->mode           = mode;
        ),
 
-- 
2.41.0