From 34173a4aad7a641e72b70f9927ca797746fbce69 Mon Sep 17 00:00:00 2001 From: Miguel Ojeda Date: Tue, 20 Feb 2007 13:58:00 -0800 Subject: [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 Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/auxdisplay/cfag12864b.c | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) (limited to 'drivers/auxdisplay/cfag12864b.c') diff --git a/drivers/auxdisplay/cfag12864b.c b/drivers/auxdisplay/cfag12864b.c index 889583d..cb44cb4 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: -- cgit v1.1