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Commit d1d73578 authored by Uwe Kleine-König's avatar Uwe Kleine-König Committed by Linus Torvalds
Browse files

backlight: grab ops_lock before testing bd->ops 



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 c835ee7f ("backlight: Add suspend/resume
support to the backlight core") in Jan 2009.

Signed-off-by: default avatarUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: default avatarRichard Purdie <rpurdie@linux.intel.com>
Cc: <stable@kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent b38eeaae

drivers/video/backlight/backlight.c

+6 −6
Original line number Diff line number Diff line
@@ -197,12 +197,12 @@ static int backlight_suspend(struct device *dev, pm_message_t state) 
{

	struct backlight_device *bd = to_backlight_device(dev);



	if (bd->ops->options & BL_CORE_SUSPENDRESUME) {

	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 device *dev) 
{

	struct backlight_device *bd = to_backlight_device(dev);



	if (bd->ops->options & BL_CORE_SUSPENDRESUME) {

	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;

}