If release is part of frontend ops then it is called in the
course of dvb_frontend_detach. The process also decrements
the module usage count. The problem is if the lgdt3306a
driver is reached via i2c_new_device, then when it is
eventually destroyed remove is called, which further
decrements the module usage count to negative. After this
occurs the driver is in a bad state and no longer works.
Also fixed by NULLing out the release callback is a double
kfree of state, which introduces arbitrary oopses/GPF.
This problem is only currently reachable via the em28xx driver.
On disconnect of Hauppauge SoloHD before:
lsmod | grep lgdt3306a
lgdt3306a 28672 -1
i2c_mux 16384 1 lgdt3306a
On disconnect of Hauppauge SoloHD after:
lsmod | grep lgdt3306a
lgdt3306a 28672 0
i2c_mux 16384 1 lgdt3306a
Signed-off-by: Brad Love <brad@nextdimension.cc>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
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