[PATCH] cfag12864b: fix crash when built-in and no parport present
The problem comes when ks0108/cfag12864b are built-in and no parallel port is
present. ks0108_init() is called first, as it should be, but fails to load
(as there is no parallel port to use).
After that, cfag12864b_init() gets called, without knowing anything about
ks0108 failed, and calls ks0108_writecontrol(), which dereferences an
uninitialized pointer.
Init order is OK, I think. The problem is how to stop cfag12864b_init() being
called if ks0108 failed to load. modprobe does it for us, but, how when
built-in?
Signed-off-by: Miguel Ojeda Sandonis <maxextreme@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/auxdisplay/cfag12864bfb.c b/drivers/auxdisplay/cfag12864bfb.c
index 94765e7..66fafbb 100644
--- a/drivers/auxdisplay/cfag12864bfb.c
+++ b/drivers/auxdisplay/cfag12864bfb.c
@@ -137,7 +137,14 @@
static int __init cfag12864bfb_init(void)
{
- int ret;
+ int ret = -EINVAL;
+
+ /* cfag12864b_init() must be called first */
+ if (!cfag12864b_isinited()) {
+ printk(KERN_ERR CFAG12864BFB_NAME ": ERROR: "
+ "cfag12864b is not initialized\n");
+ goto none;
+ }
if (cfag12864b_enable()) {
printk(KERN_ERR CFAG12864BFB_NAME ": ERROR: "
@@ -162,6 +169,7 @@
}
}
+none:
return ret;
}