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authorMiguel Ojeda <maxextreme@gmail.com>2007-02-20 16:58:00 -0500
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-02-20 20:10:14 -0500
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);
312EXPORT_SYMBOL_GPL(cfag12864b_isenabled); 312EXPORT_SYMBOL_GPL(cfag12864b_isenabled);
313 313
314/* 314/*
315 * Is the module inited?
316 */
317
318static unsigned char cfag12864b_inited;
319unsigned char cfag12864b_isinited(void)
320{
321 return cfag12864b_inited;
322}
323EXPORT_SYMBOL_GPL(cfag12864b_isinited);
324
325/*
315 * Module Init & Exit 326 * Module Init & Exit
316 */ 327 */
317 328
@@ -319,6 +330,13 @@ static int __init cfag12864b_init(void)
319{ 330{
320 int ret = -EINVAL; 331 int ret = -EINVAL;
321 332
333 /* ks0108_init() must be called first */
334 if (!ks0108_isinited()) {
335 printk(KERN_ERR CFAG12864B_NAME ": ERROR: "
336 "ks0108 is not initialized\n");
337 goto none;
338 }
339
322 if (PAGE_SIZE < CFAG12864B_SIZE) { 340 if (PAGE_SIZE < CFAG12864B_SIZE) {
323 printk(KERN_ERR CFAG12864B_NAME ": ERROR: " 341 printk(KERN_ERR CFAG12864B_NAME ": ERROR: "
324 "page size (%i) < cfag12864b size (%i)\n", 342 "page size (%i) < cfag12864b size (%i)\n",
@@ -354,6 +372,7 @@ static int __init cfag12864b_init(void)
354 cfag12864b_clear(); 372 cfag12864b_clear();
355 cfag12864b_on(); 373 cfag12864b_on();
356 374
375 cfag12864b_inited = 1;
357 return 0; 376 return 0;
358 377
359cachealloced: 378cachealloced: