From: Al Viro <viro@ZenIV.linux.org.uk>
Date: Tue, 19 Nov 2013 01:20:43 +0000 (+0000)
Subject: seq_file: always clear m->count when we free m->buf
X-Git-Tag: firefly_0821_release~176^2~4928
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=801a76050bcf8d4e500eb8d048ff6265f37a61c8;p=firefly-linux-kernel-4.4.55.git

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>
---

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);