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[PATCH] cfag12864b: fix crash when built-in and no parport present

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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>
This commit is contained in:
Miguel Ojeda 2007-02-20 13:58:00 -08:00 committed by Linus Torvalds
parent e627432c29
commit 34173a4aad
5 changed files with 48 additions and 1 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

19
drivers/auxdisplay/cfag12864b.c
View file

@ -311,6 +311,17 @@ EXPORT_SYMBOL_GPL(cfag12864b_enable);
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:

10
drivers/auxdisplay/cfag12864bfb.c
View file

@ -137,7 +137,14 @@ static struct platform_device *cfag12864bfb_device;
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 @@ static int __init cfag12864bfb_init(void)
}
}
none:
return ret;
}

12
drivers/auxdisplay/ks0108.c
View file

@ -110,6 +110,17 @@ EXPORT_SYMBOL_GPL(ks0108_startline);
EXPORT_SYMBOL_GPL(ks0108_address);
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 @@ static int __init ks0108_init(void)
goto registered;
}
ks0108_inited = 1;
return 0;
registered:

5
include/linux/cfag12864b.h
View file

@ -73,5 +73,10 @@ extern void cfag12864b_disable(void);
*/
extern unsigned char cfag12864b_isenabled(void);
/*
* Is the module inited?
*/
extern unsigned char cfag12864b_isinited(void);
#endif /* _CFAG12864B_H_ */

3
include/linux/ks0108.h
View file

@ -43,4 +43,7 @@ extern void ks0108_address(unsigned char address);
/* Set the controller's current page (0..7) */
extern void ks0108_page(unsigned char page);
/* Is the module inited? */
extern unsigned char ks0108_isinited(void);
#endif /* _KS0108_H_ */