From 2f9381e98471837b631743270de988e78aad1f96 Mon Sep 17 00:00:00 2001 From: Pavel Shved Date: Fri, 17 Jun 2011 06:25:11 +0000 Subject: [PATCH] gigaset: call module_put before restart of if_open() 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 Signed-off-by: David S. Miller --- drivers/isdn/gigaset/interface.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/isdn/gigaset/interface.c b/drivers/isdn/gigaset/interface.c index 59de638225fe..e35058bcd7b9 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;