From: Uwe Kleine-König Date: Wed, 24 Nov 2010 20:57:14 +0000 (-0800) Subject: backlight: grab ops_lock before testing bd->ops X-Git-Tag: v2.6.37-rc4~39 X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=commitdiff_plain;h=d1d73578e053b981c3611e5a211534290d24a5eb;p=linux.git 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 c835ee7f4154992e6 ("backlight: Add suspend/resume support to the backlight core") in Jan 2009. Signed-off-by: Uwe Kleine-König Acked-by: Richard Purdie Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/drivers/video/backlight/backlight.c b/drivers/video/backlight/backlight.c index e207810bba3c..08703299ef61 100644 --- a/drivers/video/backlight/backlight.c +++ b/drivers/video/backlight/backlight.c @@ -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); + 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); + 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; }