Gitweb:
http://git.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=e109ebd1eed2b91e3c9bb3b42cc27961f0dc22b3
Commit: e109ebd1eed2b91e3c9bb3b42cc27961f0dc22b3
Parent: 0478e62e8a04154b7bdc0dfd33ffbcabc5446e9c
Author: David Brownell <[EMAIL PROTECTED]>
AuthorDate: Wed Feb 28 20:12:40 2007 -0800
Committer: Linus Torvalds <[EMAIL PROTECTED]>
CommitDate: Thu Mar 1 14:53:37 2007 -0800
[PATCH] rtc_cmos oops fix
Fix an oops on the rtc_device_unregister() path by waiting until the last
moment before nulling the rtc->ops vector. Fix some potential oopses by
having the rtc_class_open()/rtc_class_close() interface increase the RTC's
reference count while an RTC handle is available outside the RTC framework.
Signed-off-by: David Brownell <[EMAIL PROTECTED]>
Cc: Alessandro Zummo <[EMAIL PROTECTED]>
Signed-off-by: Andrew Morton <[EMAIL PROTECTED]>
Signed-off-by: Linus Torvalds <[EMAIL PROTECTED]>
---
drivers/rtc/class.c | 14 ++++++++++----
drivers/rtc/interface.c | 3 ++-
2 files changed, 12 insertions(+), 5 deletions(-)
diff --git a/drivers/rtc/class.c b/drivers/rtc/class.c
index 7a0d8ee..04aaa63 100644
--- a/drivers/rtc/class.c
+++ b/drivers/rtc/class.c
@@ -113,10 +113,16 @@ EXPORT_SYMBOL_GPL(rtc_device_register);
*/
void rtc_device_unregister(struct rtc_device *rtc)
{
- mutex_lock(&rtc->ops_lock);
- rtc->ops = NULL;
- mutex_unlock(&rtc->ops_lock);
- class_device_unregister(&rtc->class_dev);
+ if (class_device_get(&rtc->class_dev) != NULL) {
+ mutex_lock(&rtc->ops_lock);
+ /* remove innards of this RTC, then disable it, before
+ * letting any rtc_class_open() users access it again
+ */
+ class_device_unregister(&rtc->class_dev);
+ rtc->ops = NULL;
+ mutex_unlock(&rtc->ops_lock);
+ class_device_put(&rtc->class_dev);
+ }
}
EXPORT_SYMBOL_GPL(rtc_device_unregister);
diff --git a/drivers/rtc/interface.c b/drivers/rtc/interface.c
index 6f11f6d..ef40df0 100644
--- a/drivers/rtc/interface.c
+++ b/drivers/rtc/interface.c
@@ -179,7 +179,7 @@ struct class_device *rtc_class_open(char *name)
down(&rtc_class->sem);
list_for_each_entry(class_dev_tmp, &rtc_class->children, node) {
if (strncmp(class_dev_tmp->class_id, name, BUS_ID_SIZE) == 0) {
- class_dev = class_dev_tmp;
+ class_dev = class_device_get(class_dev_tmp);
break;
}
}
@@ -197,6 +197,7 @@ EXPORT_SYMBOL_GPL(rtc_class_open);
void rtc_class_close(struct class_device *class_dev)
{
module_put(to_rtc_device(class_dev)->owner);
+ class_device_put(class_dev);
}
EXPORT_SYMBOL_GPL(rtc_class_close);
-
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