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    SubjectRe: [patch -resend] leds-lp5523: BUG() in error handling in probe()
    On Wed, Jun 27, 2012 at 5:10 PM, Dan Carpenter <dan.carpenter@oracle.com> wrote:
    > Inside the error handling in lp5523_init_led(), there is a place that
    > calls to led_classdev_unregister().  When we unregister the LED drivers,
    > it tries to set the brightness to OFF.  In this driver setting the
    > brightness is done through a work queue and the work queue hasn't been
    > initialized yet.
    >
    > The result is that we trigger a WARN_ON() in the __queue_work().
    >
    > The fix is to move the INIT_WORK() in front of the call to
    > lp5523_init_led().
    >

    Thanks for resending this, I applied this in my for-next branch.

    > Matt Renzelmann found this using a bug finding tool.

    Just be curious, what's kind of the tool here?

    -Bryan

    >
    > Reported-by: Matt Renzelmann <mjr@cs.wisc.edu>
    > Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
    > ---
    > I don't have this hardware, so I can't test it.  I originally sent this
    > on Fri, 13 Apr 2012, and that was before Bryan Wu took on the LED
    > subsystem.  Also when I sent it, the WARN_ON() in __queue_work() was
    > a BUG_ON() so I've updated the commit message.
    >
    > diff --git a/drivers/leds/leds-lp5523.c b/drivers/leds/leds-lp5523.c
    > index 857a3e1..e8a2712 100644
    > --- a/drivers/leds/leds-lp5523.c
    > +++ b/drivers/leds/leds-lp5523.c
    > @@ -943,6 +943,9 @@ static int __devinit lp5523_probe(struct i2c_client *client,
    >                if (pdata->led_config[i].led_current == 0)
    >                        continue;
    >
    > +               INIT_WORK(&chip->leds[led].brightness_work,
    > +                       lp5523_led_brightness_work);
    > +
    >                ret = lp5523_init_led(&chip->leds[led], &client->dev, i, pdata);
    >                if (ret) {
    >                        dev_err(&client->dev, "error initializing leds\n");
    > @@ -956,9 +959,6 @@ static int __devinit lp5523_probe(struct i2c_client *client,
    >                          LP5523_REG_LED_CURRENT_BASE + chip->leds[led].chan_nr,
    >                          chip->leds[led].led_current);
    >
    > -               INIT_WORK(&(chip->leds[led].brightness_work),
    > -                       lp5523_led_brightness_work);
    > -
    >                led++;
    >        }
    >



    --
    Bryan Wu <bryan.wu@canonical.com>
    Kernel Developer    +86.186-168-78255 Mobile
    Canonical Ltd.      www.canonical.com
    Ubuntu - Linux for human beings | www.ubuntu.com
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