| Date | Tue, 07 Dec 2010 17:00:10 -0800 | From | Greg KH <> | Subject | [233/289] backlight: grab ops_lock before testing bd->ops |
| |
2.6.36-stable review patch. If anyone has any objections, please let us know.
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From: =?UTF-8?q?Uwe=20Kleine-K=C3=B6nig?= <u.kleine-koenig@pengutronix.de>
commit d1d73578e053b981c3611e5a211534290d24a5eb upstream.
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@pengutronix.de> Acked-by: Richard Purdie <rpurdie@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
--- drivers/video/backlight/backlight.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-)
--- a/drivers/video/backlight/backlight.c +++ b/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; }
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