Zefan Li,
On Wed, 2016-10-12 at 20:33 +0800, lizf@xxxxxxxxxx wrote:
> When shutting down the device, the struct ser_cardstate must not be
> kfree()d immediately after the call to platform_device_unregister()
> since the embedded struct platform_device is still in use.
> Move the kfree() call to the release method instead.
>
> Signed-off-by: Tilman Schmidt <tilman@xxxxxxx>
> Fixes: 2869b23e4b95 ("drivers/isdn/gigaset: new M101 driver (v2)")
> Reported-by: Sasha Levin <sasha.levin@xxxxxxxxxx>
> Signed-off-by: Paul Bolle <pebolle@xxxxxxxxxx>
> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
> Signed-off-by: Zefan Li <lizefan@xxxxxxxxxx>
There has been a follow up for this fix. I'll have to dive into my
archive to see why that was needed.
It was complicated, because there has been a short period in which this
fix was correct. Something like that, I'm speaking from memory.
(Perhaps Tilman's memory is less imperfect.)
I'll try get back to this shortly (in a day or so).
Thanks,
Paul Bolle
> ---
> drivers/isdn/gigaset/ser-gigaset.c | 10 +++++++---
> 1 file changed, 7 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/isdn/gigaset/ser-gigaset.c
> b/drivers/isdn/gigaset/ser-gigaset.c
> index 6f3fd4c..3cdfcd0 100644
> --- a/drivers/isdn/gigaset/ser-gigaset.c
> +++ b/drivers/isdn/gigaset/ser-gigaset.c
> @@ -371,19 +371,23 @@ static void gigaset_freecshw(struct cardstate
> *cs)
> tasklet_kill(&cs->write_tasklet);
> if (!cs->hw.ser)
> return;
> - dev_set_drvdata(&cs->hw.ser->dev.dev, NULL);
> platform_device_unregister(&cs->hw.ser->dev);
> - kfree(cs->hw.ser);
> - cs->hw.ser = NULL;
> }
>
> static void gigaset_device_release(struct device *dev)
> {
> struct platform_device *pdev = to_platform_device(dev);
> + struct cardstate *cs = dev_get_drvdata(dev);
>
> /* adapted from platform_device_release() in
> drivers/base/platform.c */
> kfree(dev->platform_data);
> kfree(pdev->resource);
> +
> + if (!cs)
> + return;
> + dev_set_drvdata(dev, NULL);
> + kfree(cs->hw.ser);
> + cs->hw.ser = NULL;
> }
>
> /*
--
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