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authorBrad Love <brad@nextdimension.cc>2018-01-04 19:04:17 -0500
committerMauro Carvalho Chehab <mchehab@s-opensource.com>2018-03-06 04:35:28 -0500
commit5b3a8e906973540b61dbf402c6b6f8d64d4ae119 (patch)
treec38f1fa1b4b8faeb3c5ae6d0037459b3cda1ecc1 /drivers/media
parentcc4406d919d25f2d8667a0eebab179dadaaa1cb5 (diff)
downloadlinux-5b3a8e906973540b61dbf402c6b6f8d64d4ae119.tar.gz
media: lgdt3306a: Set fe ops.release to NULL if probed
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>
Diffstat (limited to 'drivers/media')
-rw-r--r--drivers/media/dvb-frontends/lgdt3306a.c1
1 files changed, 1 insertions, 0 deletions
diff --git a/drivers/media/dvb-frontends/lgdt3306a.c b/drivers/media/dvb-frontends/lgdt3306a.c
index 6356815cf3e1..d2477edae197 100644
--- a/drivers/media/dvb-frontends/lgdt3306a.c
+++ b/drivers/media/dvb-frontends/lgdt3306a.c
@@ -2177,6 +2177,7 @@ static int lgdt3306a_probe(struct i2c_client *client,
 
 	i2c_set_clientdata(client, fe->demodulator_priv);
 	state = fe->demodulator_priv;
+	state->frontend.ops.release = NULL;
 
 	/* create mux i2c adapter for tuner */
 	state->muxc = i2c_mux_alloc(client->adapter, &client->dev,