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From:   Wenwen Wang <wenwen@cs.uga.edu>
To:     Wenwen Wang <wenwen@cs.uga.edu>
Cc:     Chas Williams <3chas3@gmail.com>,
        linux-atm-general@lists.sourceforge.net (moderated list:ATM),
        netdev@vger.kernel.org (open list:ATM),
        linux-kernel@vger.kernel.org (open list)
Subject: [PATCH v2] firestream: fix memory leaks
Date:   Sat, 25 Jan 2020 14:33:29 +0000
Message-Id: <20200125143329.11766-1-wenwen@cs.uga.edu>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

In fs_open(), 'vcc' is allocated through kmalloc() and assigned to
'atm_vcc->dev_data.' In the following execution, if an error occurs, e.g.,
there is no more free channel, an error code EBUSY or ENOMEM will be
returned. However, 'vcc' is not deallocated, leading to memory leaks. Note
that, in normal cases where fs_open() returns 0, 'vcc' will be deallocated
in fs_close(). But, if fs_open() fails, there is no guarantee that
fs_close() will be invoked.

To fix this issue, deallocate 'vcc' before the error code is returned.

Signed-off-by: Wenwen Wang <wenwen@cs.uga.edu>
---
 drivers/atm/firestream.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/atm/firestream.c b/drivers/atm/firestream.c
index aad00d2b28f5..cc87004d5e2d 100644
--- a/drivers/atm/firestream.c
+++ b/drivers/atm/firestream.c
@@ -912,6 +912,7 @@ static int fs_open(struct atm_vcc *atm_vcc)
 			}
 			if (!to) {
 				printk ("No more free channels for FS50..\n");
+				kfree(vcc);
 				return -EBUSY;
 			}
 			vcc->channo = dev->channo;
@@ -922,6 +923,7 @@ static int fs_open(struct atm_vcc *atm_vcc)
 			if (((DO_DIRECTION(rxtp) && dev->atm_vccs[vcc->channo])) ||
 			    ( DO_DIRECTION(txtp) && test_bit (vcc->channo, dev->tx_inuse))) {
 				printk ("Channel is in use for FS155.\n");
+				kfree(vcc);
 				return -EBUSY;
 			}
 		}
@@ -935,6 +937,7 @@ static int fs_open(struct atm_vcc *atm_vcc)
 			    tc, sizeof (struct fs_transmit_config));
 		if (!tc) {
 			fs_dprintk (FS_DEBUG_OPEN, "fs: can't alloc transmit_config.\n");
+			kfree(vcc);
 			return -ENOMEM;
 		}
 
-- 
2.17.1