From: Takashi Iwai <tiwai@suse.de>

Subject: media: dvb_net: kABI workaround

Patch-mainline: Never, kABI workaround

References: CVE-2022-45886 bsc#1205760

For keeping the kABI workaround, the newly introduced remove_mutex

of dvb_net to be a global one.  It's not urgent for performance,

so we can live with that.

Signed-off-by: Takashi Iwai <tiwai@suse.de>

---

 drivers/media/dvb-core/dvb_net.c |   19 ++++++++++---------

 include/media/dvb_net.h          |    4 ----

 2 files changed, 10 insertions(+), 13 deletions(-)

--- a/drivers/media/dvb-core/dvb_net.c

+++ b/drivers/media/dvb-core/dvb_net.c

@@ -57,6 +57,8 @@

 #include <media/dvb_demux.h>

 #include <media/dvb_net.h>

+static DEFINE_MUTEX(remove_mutex);

+

 static inline __u32 iov_crc32( __u32 c, struct kvec *iov, unsigned int cnt )

 {

 	unsigned int j;

@@ -1570,17 +1572,17 @@ static int locked_dvb_net_open(struct in

 	struct dvb_net *dvbnet = dvbdev->priv;

 	int ret;

-	if (mutex_lock_interruptible(&dvbnet->remove_mutex))

+	if (mutex_lock_interruptible(&remove_mutex))

 		return -ERESTARTSYS;

 	if (dvbnet->exit) {

-		mutex_unlock(&dvbnet->remove_mutex);

+		mutex_unlock(&remove_mutex);

 		return -ENODEV;

 	}

 	ret = dvb_generic_open(inode, file);

-	mutex_unlock(&dvbnet->remove_mutex);

+	mutex_unlock(&remove_mutex);

 	return ret;

 }

@@ -1590,15 +1592,15 @@ static int dvb_net_close(struct inode *i

 	struct dvb_device *dvbdev = file->private_data;

 	struct dvb_net *dvbnet = dvbdev->priv;

-	mutex_lock(&dvbnet->remove_mutex);

+	mutex_lock(&remove_mutex);

 	dvb_generic_release(inode, file);

 	if (dvbdev->users == 1 && dvbnet->exit == 1) {

-		mutex_unlock(&dvbnet->remove_mutex);

+		mutex_unlock(&remove_mutex);

 		wake_up(&dvbdev->wait_queue);

 	} else {

-		mutex_unlock(&dvbnet->remove_mutex);

+		mutex_unlock(&remove_mutex);

 	}

 	return 0;

@@ -1627,9 +1629,9 @@ void dvb_net_release (struct dvb_net *dv

 {

 	int i;

-	mutex_lock(&dvbnet->remove_mutex);

+	mutex_lock(&remove_mutex);

 	dvbnet->exit = 1;

-	mutex_unlock(&dvbnet->remove_mutex);

+	mutex_unlock(&remove_mutex);

 	if (dvbnet->dvbdev->users < 1)

 		wait_event(dvbnet->dvbdev->wait_queue,

@@ -1652,7 +1654,6 @@ int dvb_net_init (struct dvb_adapter *ad

 	int i;

 	mutex_init(&dvbnet->ioctl_mutex);

-	mutex_init(&dvbnet->remove_mutex);

 	dvbnet->demux = dmx;

 	for (i=0; i

--- a/include/media/dvb_net.h

+++ b/include/media/dvb_net.h

@@ -41,9 +41,6 @@

  * @exit:		flag to indicate when the device is being removed.

  * @demux:		pointer to &struct dmx_demux.

  * @ioctl_mutex:	protect access to this struct.

- * @remove_mutex:	mutex that avoids a race condition between a callback

- *			called when the hardware is disconnected and the

- *			file_operations of dvb_net.

  *

  * Currently, the core supports up to %DVB_NET_DEVICES_MAX (10) network

  * devices.

@@ -56,7 +53,6 @@ struct dvb_net {

 	unsigned int exit:1;

 	struct dmx_demux *demux;

 	struct mutex ioctl_mutex;

-	struct mutex remove_mutex;

 };

 /**