Messages in this thread Patch in this message | | | Date | Mon, 22 Nov 2010 11:05:32 +0100 | From | Uwe Kleine-König <> | Subject | Re: [PATCH] backlight: grab ops_lock before testing bd->ops |
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Hello,
On Mon, Nov 22, 2010 at 09:59:07AM +0000, Richard Purdie wrote: > On Mon, 2010-11-22 at 10:43 +0100, Uwe Kleine-König wrote: > > 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. > > > > Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> > > Acked-by: Richard Purdie <rpurdie@linux.intel.com> The problem was introduced by c835ee7f4154992e6cf0674d7ee136f5d36247a4 (that is in 2.6.29-rc1). Is this relevant for stable?
Best regards Uwe > > --- > > drivers/video/backlight/backlight.c | 12 ++++++------ > > 1 files changed, 6 insertions(+), 6 deletions(-) > > > > diff --git a/drivers/video/backlight/backlight.c b/drivers/video/backlight/backlight.c > > index e207810..0870329 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; > > } > > >
-- Pengutronix e.K. | Uwe Kleine-König | Industrial Linux Solutions | http://www.pengutronix.de/ | -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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