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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 <shved@ispras.ru>
Signed-off-by: David S. Miller <davem@conan.davemloft.net>
This commit is contained in:
Pavel Shved 2011-06-17 06:25:11 +00:00 committed by David S. Miller
parent d0fd64c1de
commit 2f9381e984
1 changed files with 3 additions and 1 deletions
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4
drivers/isdn/gigaset/interface.c
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@ -156,8 +156,10 @@ static int if_open(struct tty_struct *tty, struct file *filp)
if (!cs || !try_module_get(cs->driver->owner)) if (!cs || !try_module_get(cs->driver->owner))
return -ENODEV; return -ENODEV;
if (mutex_lock_interruptible(&cs->mutex)) if (mutex_lock_interruptible(&cs->mutex)) {
module_put(cs->driver->owner);
return -ERESTARTSYS; return -ERESTARTSYS;
}
tty->driver_data = cs; tty->driver_data = cs;
++cs->open_count; ++cs->open_count;