seq_file: always clear m->count when we free m->buf

Once we'd freed m->buf, m->count should become zero - we have no valid
contents reachable via m->buf.

Reported-by: Charley (Hao Chuan) Chu <charley.chu@broadcom.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 2 insertions, 1 deletions

diff --git a/fs/seq_file.c b/fs/seq_file.c
index 1cd2388ca5bd..1d641bb108d2 100644
--- a/fs/seq_file.c
+++ b/fs/seq_file.c
@@ -136,6 +136,7 @@ static int traverse(struct seq_file *m, loff_t offset)
 Eoverflow:
         m->op->stop(m, p);
         kfree(m->buf);
+        m->count = 0;
         m->buf = kmalloc(m->size <<= 1, GFP_KERNEL);
         return !m->buf ? -ENOMEM : -EAGAIN;
 }
@@ -232,10 +233,10 @@ ssize_t seq_read(struct file *file, char __user *buf, size_t size, loff_t *ppos)
                         goto Fill;
                 m->op->stop(m, p);
                 kfree(m->buf);
+                m->count = 0;
                 m->buf = kmalloc(m->size <<= 1, GFP_KERNEL);
                 if (!m->buf)
                         goto Enomem;
-                m->count = 0;
                 m->version = 0;
                 pos = m->index;
                 p = m->op->start(m, &pos);