fs/proc/task_mmu: Fix linked list damage from c4e6b1dfcb6f99

Fix reset of mas and initialize vma_start.

Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>

diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 501d27ae2b77224872ff87041fd094a28c8f2faa..9c703b96a36e38c717144a1c8191e71382ab4e34 100644 (file)
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -842,7 +842,7 @@ static int show_smaps_rollup(struct seq_file *m, void *v)
        struct mem_size_stats mss;
        struct mm_struct *mm = priv->mm;
        struct vm_area_struct *vma;
-       unsigned long vma_start, last_vma_end = 0;
+       unsigned long vma_start = 0, last_vma_end = 0;
        int ret = 0;
        MA_STATE(mas, &mm->mm_mt, 0, 0);
 
@@ -864,11 +864,11 @@ static int show_smaps_rollup(struct seq_file *m, void *v)
        hold_task_mempolicy(priv);
        vma = mas_find(&mas, 0);
 
-       if (vma)
-               vma_start = vma->vm_start;
+       if (unlikely(!vma))
+               goto empty_set;
 
-       mas_set(&mas, 0);
-       mas_for_each(&mas, vma, -1) {
+       vma_start = vma->vm_start;
+       do {
                smap_gather_stats(vma, &mss, 0);
                last_vma_end = vma->vm_end;
 
@@ -936,8 +936,9 @@ static int show_smaps_rollup(struct seq_file *m, void *v)
                                smap_gather_stats(vma, &mss, last_vma_end);
                }
                /* Case 2 above */
-       }
+       } while ((vma = mas_find(&mas, -1)) != NULL);
 
+empty_set:
        show_vma_header_prefix(m, vma_start, last_vma_end, 0, 0, 0, 0);
        seq_pad(m, ' ');
        seq_puts(m, "[rollup]\n");