Patch "seq_file: fix incomplete reset on read from zero offset" has been added to the 4.15-stable tree

This is a note to let you know that I've just added the patch titled

seq_file: fix incomplete reset on read from zero offset

to the 4.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
seq_file-fix-incomplete-reset-on-read-from-zero-offset.patch
and it can be found in the queue-4.15 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Miklos Szeredi <[email protected]>
Date: Wed, 15 Nov 2017 11:34:58 +0100
Subject: seq_file: fix incomplete reset on read from zero offset

From: Miklos Szeredi <[email protected]>

commit cf5eebae2cd28d37581507668605f4d23cd7218d upstream.

When resetting iterator on a zero offset we need to discard any data already in the buffer (count), and private state of the iterator (version).

For example this bug results in first line being repeated in /proc/mounts if doing a zero size read before a non-zero size read.

---
 fs/seq_file.c |    5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

@@ -181,8 +181,11 @@ ssize_t seq_read(struct file *file, char
 	 * if request is to read from zero offset, reset iterator to first
 	 * record as it might have been already advanced by previous requests
 	 */
-	if (*ppos == 0)
+	if (*ppos == 0) {
 		m->index = 0;
+		m->version = 0;
+		m->count = 0;
+	}
 
 	/* Don't assume *ppos is where we left it */
 	if (unlikely(*ppos != m->read_pos)) {

Patches currently in stable-queue which might be from [email protected] are

queue-4.15/seq_file-fix-incomplete-reset-on-read-from-zero-offset.patch