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Message-Id: <1308327913-23220-2-git-send-email-shved@ispras.ru>
Date: Fri, 17 Jun 2011 20:25:11 +0400
From: Pavel Shved <shved@...ras.ru>
To: Hansjoerg Lipp <hjlipp@....de> (maintainer:GIGASET ISDN DRIVERS)
Cc: Pavel Shved <shved@...ras.ru>,
Tilman Schmidt <tilman@...p.cc> (maintainer:GIGASET ISDN DRIVERS),
Karsten Keil <isdn@...ux-pingi.de> (maintainer:ISDN SUBSYSTEM),
gigaset307x-common@...ts.sourceforge.net (open list:GIGASET ISDN
DRIVERS), netdev@...r.kernel.org (open list:ISDN SUBSYSTEM),
linux-kernel@...r.kernel.org (open list), ldv-project@...ras.ru
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 <shved@...ras.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
--
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