[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/ks0108.c b/drivers/auxdisplay/ks0108.c
index a637575..e6c3646 100644
--- a/drivers/auxdisplay/ks0108.c
+++ b/drivers/auxdisplay/ks0108.c
@@ -111,6 +111,17 @@
EXPORT_SYMBOL_GPL(ks0108_page);
/*
+ * Is the module inited?
+ */
+
+static unsigned char ks0108_inited;
+unsigned char ks0108_isinited(void)
+{
+ return ks0108_inited;
+}
+EXPORT_SYMBOL_GPL(ks0108_isinited);
+
+/*
* Module Init & Exit
*/
@@ -142,6 +153,7 @@
goto registered;
}
+ ks0108_inited = 1;
return 0;
registered: