linux-kernel - [PATCH] TTY: memory leakage in tty_buffer

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Message-ID: <1372236670.2390.12.camel@bichao>
Date:	Wed, 26 Jun 2013 16:51:10 +0800
From:	channing <chao.bi@...el.com>
To:	gregkh@...uxfoundation.org, jslaby@...e.cz
Cc:	linux-kernel@...r.kernel.org
Subject: [PATCH] TTY: memory leakage in tty_buffer_find()


In tty_buffer_find(), it scans all tty buffers in
free buffer queue, if it finds matched one,
tty->buf.free will point to matched one's next buffer,
so tty buffers that ahead of matched one are removed
from free queue, they will never be used but they
are not released, then memory leak happen.

This patch is to make tty_buffer_find() only extract
the matched tty buffer, and keep others left inside
free queue, so that they could be found and used next
time.

Signed-off-by: Chao Bi <chao.bi@...el.com>
---
 drivers/tty/tty_buffer.c |    7 ++++++-
 1 files changed, 6 insertions(+), 1 deletions(-)

diff --git a/drivers/tty/tty_buffer.c b/drivers/tty/tty_buffer.c
index 9121c1f..7b10f7a 100644
--- a/drivers/tty/tty_buffer.c
+++ b/drivers/tty/tty_buffer.c
@@ -178,10 +178,14 @@ void tty_buffer_flush(struct tty_struct *tty)
 static struct tty_buffer *tty_buffer_find(struct tty_port *port, size_t size)
 {
 	struct tty_buffer **tbh = &port->buf.free;
+	struct tty_buffer *prev = NULL;
 	while ((*tbh) != NULL) {
 		struct tty_buffer *t = *tbh;
 		if (t->size >= size) {
-			*tbh = t->next;
+			if (prev == NULL)
+				*tbh = t->next;
+			else
+				prev->next = t->next;
 			t->next = NULL;
 			t->used = 0;
 			t->commit = 0;
@@ -189,6 +193,7 @@ static struct tty_buffer *tty_buffer_find(struct tty_port *port, size_t size)
 			port->buf.memory_used += t->size;
 			return t;
 		}
+		prev = t;
 		tbh = &((*tbh)->next);
 	}
 	/* Round the buffer size out */
-- 
1.7.1



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