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Commit 2f9381e9 authored by Pavel Shved's avatar Pavel Shved Committed by David S. Miller
Browse files

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: default avatarPavel Shved <shved@ispras.ru>
Signed-off-by: default avatarDavid S. Miller <davem@conan.davemloft.net>
parent d0fd64c1

drivers/isdn/gigaset/interface.c

+3 −1
Original line number Diff line number Diff line
@@ -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;