dvb-usb: move data_mutex to struct dvb_usb_device

The data_mutex is initialized too late, as it is needed for
each device driver's power control, causing an OOPS:

    dvb-usb: found a 'TerraTec/qanu USB2.0 Highspeed DVB-T Receiver' in warm state.
    BUG: unable to handle kernel NULL pointer dereference at           (null)
    IP: [<ffffffff846617af>] __mutex_lock_slowpath+0x6f/0x100 PGD 0
    Oops: 0002 [#1] SMP
    Modules linked in: dvb_usb_cinergyT2(+) dvb_usb
    CPU: 0 PID: 2029 Comm: modprobe Not tainted 4.9.0-rc4-dvbmod #24
    Hardware name: FUJITSU LIFEBOOK A544/FJNBB35 , BIOS Version 1.17 05/09/2014
    task: ffff88020e943840 task.stack: ffff8801f36ec000
    RIP: 0010:[<ffffffff846617af>]  [<ffffffff846617af>] __mutex_lock_slowpath+0x6f/0x100
    RSP: 0018:ffff8801f36efb10  EFLAGS: 00010282
    RAX: 0000000000000000 RBX: ffff88021509bdc8 RCX: 00000000c0000100
    RDX: 0000000000000001 RSI: 0000000000000000 RDI: ffff88021509bdcc
    RBP: ffff8801f36efb58 R08: ffff88021f216320 R09: 0000000000100000
    R10: ffff88021f216320 R11: 00000023fee6c5a1 R12: ffff88020e943840
    R13: ffff88021509bdcc R14: 00000000ffffffff R15: ffff88021509bdd0
    FS:  00007f21adb86740(0000) GS:ffff88021f200000(0000) knlGS:0000000000000000
    CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
    CR2: 0000000000000000 CR3: 0000000215bce000 CR4: 00000000001406f0
    Call Trace:
       mutex_lock+0x16/0x25
       cinergyt2_power_ctrl+0x1f/0x60 [dvb_usb_cinergyT2]
       dvb_usb_device_init+0x21e/0x5d0 [dvb_usb]
       cinergyt2_usb_probe+0x21/0x50 [dvb_usb_cinergyT2]
       usb_probe_interface+0xf3/0x2a0
       driver_probe_device+0x208/0x2b0
       __driver_attach+0x87/0x90
       driver_probe_device+0x2b0/0x2b0
       bus_for_each_dev+0x52/0x80
       bus_add_driver+0x1a3/0x220
       driver_register+0x56/0xd0
       usb_register_driver+0x77/0x130
       do_one_initcall+0x46/0x180
       free_vmap_area_noflush+0x38/0x70
       kmem_cache_alloc+0x84/0xc0
       do_init_module+0x50/0x1be
       load_module+0x1d8b/0x2100
       find_symbol_in_section+0xa0/0xa0
       SyS_finit_module+0x89/0x90
       entry_SYSCALL_64_fastpath+0x13/0x94
    Code: e8 a7 1d 00 00 8b 03 83 f8 01 0f 84 97 00 00 00 48 8b 43 10 4c 8d 7b 08 48 89 63 10 4c 89 3c 24 41 be ff ff ff ff 48 89 44 24 08 <48> 89 20 4c 89 64 24 10 eb 1a 49 c7 44 24 08 02 00 00 00 c6 43 RIP  [<ffffffff846617af>] __mutex_lock_slowpath+0x6f/0x100 RSP <ffff8801f36efb10>
    CR2: 0000000000000000

So, move it to the struct dvb_usb_device and initialize it
before calling the driver's callbacks.

Reported-by: Jörg Otte <jrg.otte@gmail.com>
Tested-by: Jörg Otte <jrg.otte@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 17 insertions, 23 deletions

diff --git a/drivers/media/usb/dvb-usb/dtt200u.c b/drivers/media/usb/dvb-usb/dtt200u.c
index f88572c7ae7c..fcbff7fb0c4e 100644
--- a/drivers/media/usb/dvb-usb/dtt200u.c
+++ b/drivers/media/usb/dvb-usb/dtt200u.c
@@ -22,7 +22,6 @@ DVB_DEFINE_MOD_OPT_ADAPTER_NR(adapter_nr);
 
 struct dtt200u_state {
 	unsigned char data[80];
-	struct mutex data_mutex;
 };
 
 static int dtt200u_power_ctrl(struct dvb_usb_device *d, int onoff)
@@ -30,23 +29,24 @@ static int dtt200u_power_ctrl(struct dvb_usb_device *d, int onoff)
 	struct dtt200u_state *st = d->priv;
 	int ret = 0;
 
-	mutex_lock(&st->data_mutex);
+	mutex_lock(&d->data_mutex);
 
 	st->data[0] = SET_INIT;
 
 	if (onoff)
 		ret = dvb_usb_generic_write(d, st->data, 2);
 
-	mutex_unlock(&st->data_mutex);
+	mutex_unlock(&d->data_mutex);
 	return ret;
 }
 
 static int dtt200u_streaming_ctrl(struct dvb_usb_adapter *adap, int onoff)
 {
-	struct dtt200u_state *st = adap->dev->priv;
+	struct dvb_usb_device *d = adap->dev;
+	struct dtt200u_state *st = d->priv;
 	int ret;
 
-	mutex_lock(&st->data_mutex);
+	mutex_lock(&d->data_mutex);
 	st->data[0] = SET_STREAMING;
 	st->data[1] = onoff;
 
@@ -61,26 +61,27 @@ static int dtt200u_streaming_ctrl(struct dvb_usb_adapter *adap, int onoff)
 	ret = dvb_usb_generic_write(adap->dev, st->data, 1);
 
 ret:
-	mutex_unlock(&st->data_mutex);
+	mutex_unlock(&d->data_mutex);
 
 	return ret;
 }
 
 static int dtt200u_pid_filter(struct dvb_usb_adapter *adap, int index, u16 pid, int onoff)
 {
-	struct dtt200u_state *st = adap->dev->priv;
+	struct dvb_usb_device *d = adap->dev;
+	struct dtt200u_state *st = d->priv;
 	int ret;
 
 	pid = onoff ? pid : 0;
 
-	mutex_lock(&st->data_mutex);
+	mutex_lock(&d->data_mutex);
 	st->data[0] = SET_PID_FILTER;
 	st->data[1] = index;
 	st->data[2] = pid & 0xff;
 	st->data[3] = (pid >> 8) & 0x1f;
 
 	ret = dvb_usb_generic_write(adap->dev, st->data, 4);
-	mutex_unlock(&st->data_mutex);
+	mutex_unlock(&d->data_mutex);
 
 	return ret;
 }
@@ -91,7 +92,7 @@ static int dtt200u_rc_query(struct dvb_usb_device *d)
 	u32 scancode;
 	int ret;
 
-	mutex_lock(&st->data_mutex);
+	mutex_lock(&d->data_mutex);
 	st->data[0] = GET_RC_CODE;
 
 	ret = dvb_usb_generic_rw(d, st->data, 1, st->data, 5, 0);
@@ -126,7 +127,7 @@ static int dtt200u_rc_query(struct dvb_usb_device *d)
 		deb_info("st->data: %*ph\n", 5, st->data);
 
 ret:
-	mutex_unlock(&st->data_mutex);
+	mutex_unlock(&d->data_mutex);
 	return ret;
 }
 
@@ -145,24 +146,17 @@ static struct dvb_usb_device_properties wt220u_miglia_properties;
 static int dtt200u_usb_probe(struct usb_interface *intf,
 		const struct usb_device_id *id)
 {
-	struct dvb_usb_device *d;
-	struct dtt200u_state *st;
-
 	if (0 == dvb_usb_device_init(intf, &dtt200u_properties,
-				     THIS_MODULE, &d, adapter_nr) ||
+				     THIS_MODULE, NULL, adapter_nr) ||
 	    0 == dvb_usb_device_init(intf, &wt220u_properties,
-				     THIS_MODULE, &d, adapter_nr) ||
+				     THIS_MODULE, NULL, adapter_nr) ||
 	    0 == dvb_usb_device_init(intf, &wt220u_fc_properties,
-				     THIS_MODULE, &d, adapter_nr) ||
+				     THIS_MODULE, NULL, adapter_nr) ||
 	    0 == dvb_usb_device_init(intf, &wt220u_zl0353_properties,
-				     THIS_MODULE, &d, adapter_nr) ||
+				     THIS_MODULE, NULL, adapter_nr) ||
 	    0 == dvb_usb_device_init(intf, &wt220u_miglia_properties,
-				     THIS_MODULE, &d, adapter_nr)) {
-		st = d->priv;
-		mutex_init(&st->data_mutex);
-
+				     THIS_MODULE, NULL, adapter_nr))
 		return 0;
-	}
 
 	return -ENODEV;
 }