[PATCH 2/3] vt: fix locking around vt_bind/vt_unbind

Imre Deak
2014-12-12T16:43:54Z

Currently vt_bind and vt_unbind access at least the con_driver object
and registered_con_driver array without holding the console lock. Fix
this by locking around the whole function in each case.

Signed-off-by: Imre Deak <imre.deak@intel.com>
---
drivers/tty/vt/vt.c | 11 +++++------
1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/drivers/tty/vt/vt.c b/drivers/tty/vt/vt.c
index 1862e89..5dd1880 100644
--- a/drivers/tty/vt/vt.c
+++ b/drivers/tty/vt/vt.c
@@ -3312,11 +3312,8 @@ static int vt_bind(struct con_driver *con)
if (first == 0 && last == MAX_NR_CONSOLES -1)
deflt = 1;

- if (first != -1) {
- console_lock();
+ if (first != -1)
do_bind_con_driver(csw, first, last, deflt);
- console_unlock();
- }

first = -1;
last = -1;
@@ -3356,9 +3353,7 @@ static int vt_unbind(struct con_driver *con)
deflt = 1;

if (first != -1) {
- console_lock();
ret = do_unbind_con_driver(csw, first, last, deflt);
- console_unlock();
if (ret != 0)
return ret;
}
@@ -3388,11 +3383,15 @@ static ssize_t store_bind(struct device *dev, struct device_attribute *attr,
struct con_driver *con = dev_get_drvdata(dev);
int bind = simple_strtoul(buf, NULL, 0);

+ console_lock();
+
if (bind)
vt_bind(con);
else
vt_unbind(con);

+ console_unlock();
+
return count;
}

--
1.8.4