[PATCH] farsync: add module_put to error path in fst_open()

[PATCH] farsync: add module_put to error path in fst_open()

[Pavel Shved]

The fst_open() function, after a successful try_module_get() may return
an error code if hdlc_open() returns it.  However, it does not put the
module on this error path.

This patch adds the necessary module_put() call.

Found by Linux Driver Verification project (linuxtesting.org).

Signed-off-by: Pavel Shved <shved@ispras.ru>
---
 drivers/net/wan/farsync.c |    4 +++-
 1 files changed, 3 insertions(+), 1 deletions(-)

diff --git a/drivers/net/wan/farsync.c b/drivers/net/wan/farsync.c
index e050bd6..777d1a4 100644
--- a/drivers/net/wan/farsync.c
+++ b/drivers/net/wan/farsync.c
@@ -2203,8 +2203,10 @@ fst_open(struct net_device *dev)
 
 	if (port->mode != FST_RAW) {
 		err = hdlc_open(dev);
-		if (err)
+		if (err) {
+			module_put(THIS_MODULE);
 			return err;
+		}
 	}
 
 	fst_openport(port);
-- 
1.7.0.2

[PATCH] gigaset: call module_put before restart of if_open()

[Pavel Shved]

if_open() calls try_module_get(), and after an attempt to lock a mutex
the if_open() function may return -ERESTARTSYS without
putting the module.  Then, when if_open() is executed again,
try_module_get() is called making the reference counter of THIS_MODULE
greater than one at successful exit from if_open().  The if_close()
function puts the module only once, and as a result it can't be
unloaded.

This patch adds module_put call before the return from if_open().

Found by Linux Driver Verification project (linuxtesting.org).

Signed-off-by: Pavel Shved <shved@ispras.ru>
---
 drivers/isdn/gigaset/interface.c |    4 +++-
 1 files changed, 3 insertions(+), 1 deletions(-)

diff --git a/drivers/isdn/gigaset/interface.c b/drivers/isdn/gigaset/interface.c
index 59de638..e35058b 100644
--- a/drivers/isdn/gigaset/interface.c
+++ b/drivers/isdn/gigaset/interface.c
@@ -156,8 +156,10 @@ static int if_open(struct tty_struct *tty, struct file *filp)
 	if (!cs || !try_module_get(cs->driver->owner))
 		return -ENODEV;
 
-	if (mutex_lock_interruptible(&cs->mutex))
+	if (mutex_lock_interruptible(&cs->mutex)) {
+		module_put(cs->driver->owner);
 		return -ERESTARTSYS;
+	}
 	tty->driver_data = cs;
 
 	++cs->open_count;
-- 
1.7.0.2

Re: [PATCH] gigaset: call module_put before restart of if_open()

[David Miller]

From: Pavel Shved <shved@ispras.ru>
Date: Fri, 17 Jun 2011 20:25:11 +0400

> if_open() calls try_module_get(), and after an attempt to lock a mutex
> the if_open() function may return -ERESTARTSYS without
> putting the module.  Then, when if_open() is executed again,
> try_module_get() is called making the reference counter of THIS_MODULE
> greater than one at successful exit from if_open().  The if_close()
> function puts the module only once, and as a result it can't be
> unloaded.
> 
> This patch adds module_put call before the return from if_open().
> 
> Found by Linux Driver Verification project (linuxtesting.org).
> 
> Signed-off-by: Pavel Shved <shved@ispras.ru>

Applied.

Re: [PATCH] farsync: add module_put to error path in fst_open()

[David Miller]

From: Pavel Shved <shved@ispras.ru>
Date: Fri, 17 Jun 2011 20:25:10 +0400

> The fst_open() function, after a successful try_module_get() may return
> an error code if hdlc_open() returns it.  However, it does not put the
> module on this error path.
> 
> This patch adds the necessary module_put() call.
> 
> Found by Linux Driver Verification project (linuxtesting.org).
> 
> Signed-off-by: Pavel Shved <shved@ispras.ru>

Applied.