diff options
| author | David Brownell <david-b@pacbell.net> | 2007-03-01 07:12:40 +0300 |
|---|---|---|
| committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-03-02 01:53:37 +0300 |
| commit | e109ebd1eed2b91e3c9bb3b42cc27961f0dc22b3 (patch) | |
| tree | 402ca61d265c59d35282b0786363dfbe32659564 | |
| parent | 0478e62e8a04154b7bdc0dfd33ffbcabc5446e9c (diff) | |
| download | linux-e109ebd1eed2b91e3c9bb3b42cc27961f0dc22b3.tar.xz | |
[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 <dbrownell@users.sourceforge.net>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | drivers/rtc/class.c | 14 | ||||
| -rw-r--r-- | 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 7a0d8ee2de9c..04aaa6347234 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 6f11f6dfdd9d..ef40df0f169d 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); |