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authorMiguel Ojeda <maxextreme@gmail.com>2007-02-20 13:58:00 -0800
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-02-20 17:10:14 -0800
commit34173a4aad7a641e72b70f9927ca797746fbce69 (patch)
treee09d2fd33dc6e14d4b76210e471c47e8fed7b2a1 /drivers/auxdisplay/cfag12864b.c
parente627432c2948d500669a6c4522f22b66f5118d64 (diff)
[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>
Diffstat (limited to 'drivers/auxdisplay/cfag12864b.c')
-rw-r--r--drivers/auxdisplay/cfag12864b.c19
1 files changed, 19 insertions, 0 deletions
diff --git a/drivers/auxdisplay/cfag12864b.c b/drivers/auxdisplay/cfag12864b.c
index 889583dfc1a6..cb44cb4f6a47 100644
--- a/drivers/auxdisplay/cfag12864b.c
+++ b/drivers/auxdisplay/cfag12864b.c
@@ -312,6 +312,17 @@ EXPORT_SYMBOL_GPL(cfag12864b_disable);
EXPORT_SYMBOL_GPL(cfag12864b_isenabled);
/*
+ * Is the module inited?
+ */
+
+static unsigned char cfag12864b_inited;
+unsigned char cfag12864b_isinited(void)
+{
+ return cfag12864b_inited;
+}
+EXPORT_SYMBOL_GPL(cfag12864b_isinited);
+
+/*
* Module Init & Exit
*/
@@ -319,6 +330,13 @@ static int __init cfag12864b_init(void)
{
int ret = -EINVAL;
+ /* ks0108_init() must be called first */
+ if (!ks0108_isinited()) {
+ printk(KERN_ERR CFAG12864B_NAME ": ERROR: "
+ "ks0108 is not initialized\n");
+ goto none;
+ }
+
if (PAGE_SIZE < CFAG12864B_SIZE) {
printk(KERN_ERR CFAG12864B_NAME ": ERROR: "
"page size (%i) < cfag12864b size (%i)\n",
@@ -354,6 +372,7 @@ static int __init cfag12864b_init(void)
cfag12864b_clear();
cfag12864b_on();
+ cfag12864b_inited = 1;
return 0;
cachealloced: