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Paul Bolle authored
The purpose of gigaset_device_release() is to kfree() the struct ser_cardstate that contains our struct device. This is done via a bit of a detour. First we make our struct device's driver_data point to the container of our struct ser_cardstate (which is a struct cardstate). In gigaset_device_release() we then retrieve that driver_data again. And after that we finally kfree() the struct ser_cardstate that was saved in the struct cardstate. All of this can be achieved much easier by using container_of() to get from our struct device to its container, struct ser_cardstate. Do so. Note that at the time the detour was implemented commit b8b2c7d8 ("base/platform: assert that dev_pm_domain callbacks are called unconditionally") had just entered the tree. That commit disconnected our platform_device and our platform_driver. These were reconnected again in v4.5-rc2 through commit 25cad69f ("base/platform: Fix platform drivers with no probe callback"). And one of the consequences of that fix was that it broke the detour via driver_data. That's because it made __device_release_driver() stop being a NOP for our struct device and actually do stuff again. One of the things it now does, is setting our driver_data to NULL. That, in turn, makes it impossible for gigaset_device_release() to get to our struct cardstate. Which has the net effect of leaking a struct ser_cardstate at every call of this driver's tty close() operation. So using container_of() has the additional benefit of actually working. Reported-by:
Dmitry Vyukov <dvyukov@google.com> Tested-by:
Dmitry Vyukov <dvyukov@google.com> Signed-off-by:
Paul Bolle <pebolle@tiscali.nl> Acked-by:
Tilman Schmidt <tilman@imap.cc> Signed-off-by:
David S. Miller <davem@davemloft.net>
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