The patch titled
backlight: grab ops_lock before testing bd->ops
has been added to the -mm tree. Its filename is
backlight-grab-ops_lock-before-testing-bd-ops.patch
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------------------------------------------------------
Subject: backlight: grab ops_lock before testing bd->ops
From: Uwe Kleine-König <u.kleine-koenig@xxxxxxxxxxxxxx>
According to the comment describing ops_lock in the definition of struct
backlight_device and when comparing with other functions in backlight.c
the mutex must be hold when checking ops to be non-NULL.
Fixes a problem added by c835ee7f4154992e6 ("backlight: Add suspend/resume
support to the backlight core") in Jan 2009.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@xxxxxxxxxxxxxx>
Acked-by: Richard Purdie <rpurdie@xxxxxxxxxxxxxxx>
Cc: <stable@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/video/backlight/backlight.c | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)
diff -puN drivers/video/backlight/backlight.c~backlight-grab-ops_lock-before-testing-bd-ops drivers/video/backlight/backlight.c
--- a/drivers/video/backlight/backlight.c~backlight-grab-ops_lock-before-testing-bd-ops
+++ a/drivers/video/backlight/backlight.c
@@ -197,12 +197,12 @@ static int backlight_suspend(struct devi
{
struct backlight_device *bd = to_backlight_device(dev);
- if (bd->ops->options & BL_CORE_SUSPENDRESUME) {
- mutex_lock(&bd->ops_lock);
+ mutex_lock(&bd->ops_lock);
+ if (bd->ops && bd->ops->options & BL_CORE_SUSPENDRESUME) {
bd->props.state |= BL_CORE_SUSPENDED;
backlight_update_status(bd);
- mutex_unlock(&bd->ops_lock);
}
+ mutex_unlock(&bd->ops_lock);
return 0;
}
@@ -211,12 +211,12 @@ static int backlight_resume(struct devic
{
struct backlight_device *bd = to_backlight_device(dev);
- if (bd->ops->options & BL_CORE_SUSPENDRESUME) {
- mutex_lock(&bd->ops_lock);
+ mutex_lock(&bd->ops_lock);
+ if (bd->ops && bd->ops->options & BL_CORE_SUSPENDRESUME) {
bd->props.state &= ~BL_CORE_SUSPENDED;
backlight_update_status(bd);
- mutex_unlock(&bd->ops_lock);
}
+ mutex_unlock(&bd->ops_lock);
return 0;
}
_
Patches currently in -mm which might be from u.kleine-koenig@xxxxxxxxxxxxxx are
linux-next.patch
backlight-grab-ops_lock-before-testing-bd-ops.patch
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