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authorEric W. Biederman <ebiederm@xmission.com>2010-01-05 17:56:02 -0800
committerDmitry Torokhov <dmitry.torokhov@gmail.com>2010-01-06 00:14:32 -0800
commit59b015133cd0034f5904a76969d73476380aac46 (patch)
tree578643cc919b7e62b5086718d5c3f9b0fee836a9 /drivers/input/mouse/psmouse-base.c
parentabf2a117c67a67fbb611913a31109d0ff66ab073 (diff)
Input: serio - fix potential deadlock when unbinding drivers
sysfs_remove_group() waits for sysfs attributes to be removed, therefore we do not need to worry about driver-specific attributes being accessed after driver has been detached from the device. In fact, attempts to take serio->drv_mutex in attribute methods may lead to the following deadlock: sysfs_read_file() fill_read_buffer() sysfs_get_active_two() psmouse_attr_show_helper() serio_pin_driver() serio_disconnect_driver() mutex_lock(&serio->drv_mutex); <--------> mutex_lock(&serio_drv_mutex); psmouse_disconnect() sysfs_remove_group(... psmouse_attr_group); .... sysfs_deactivate(); wait_for_completion(); Fix this by removing calls to serio_[un]pin_driver() and functions themselves and using driver-private mutexes to serialize access to attribute's set() methods that may change device state. Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
Diffstat (limited to 'drivers/input/mouse/psmouse-base.c')
-rw-r--r--drivers/input/mouse/psmouse-base.c32
1 files changed, 3 insertions, 29 deletions
diff --git a/drivers/input/mouse/psmouse-base.c b/drivers/input/mouse/psmouse-base.c
index 401ac6b6edd4..d59e18b24ede 100644
--- a/drivers/input/mouse/psmouse-base.c
+++ b/drivers/input/mouse/psmouse-base.c
@@ -1450,24 +1450,10 @@ ssize_t psmouse_attr_show_helper(struct device *dev, struct device_attribute *de
struct serio *serio = to_serio_port(dev);
struct psmouse_attribute *attr = to_psmouse_attr(devattr);
struct psmouse *psmouse;
- int retval;
-
- retval = serio_pin_driver(serio);
- if (retval)
- return retval;
-
- if (serio->drv != &psmouse_drv) {
- retval = -ENODEV;
- goto out;
- }
psmouse = serio_get_drvdata(serio);
- retval = attr->show(psmouse, attr->data, buf);
-
-out:
- serio_unpin_driver(serio);
- return retval;
+ return attr->show(psmouse, attr->data, buf);
}
ssize_t psmouse_attr_set_helper(struct device *dev, struct device_attribute *devattr,
@@ -1478,18 +1464,9 @@ ssize_t psmouse_attr_set_helper(struct device *dev, struct device_attribute *dev
struct psmouse *psmouse, *parent = NULL;
int retval;
- retval = serio_pin_driver(serio);
- if (retval)
- return retval;
-
- if (serio->drv != &psmouse_drv) {
- retval = -ENODEV;
- goto out_unpin;
- }
-
retval = mutex_lock_interruptible(&psmouse_mutex);
if (retval)
- goto out_unpin;
+ goto out;
psmouse = serio_get_drvdata(serio);
@@ -1519,8 +1496,7 @@ ssize_t psmouse_attr_set_helper(struct device *dev, struct device_attribute *dev
out_unlock:
mutex_unlock(&psmouse_mutex);
- out_unpin:
- serio_unpin_driver(serio);
+ out:
return retval;
}
@@ -1582,9 +1558,7 @@ static ssize_t psmouse_attr_set_protocol(struct psmouse *psmouse, void *data, co
}
mutex_unlock(&psmouse_mutex);
- serio_unpin_driver(serio);
serio_unregister_child_port(serio);
- serio_pin_driver_uninterruptible(serio);
mutex_lock(&psmouse_mutex);
if (serio->drv != &psmouse_drv) {