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, 16 insertions, 23 deletions

diff --git a/drivers/media/usb/dvb-usb/cxusb.c b/drivers/media/usb/dvb-usb/cxusb.c
index 39772812269d..243403081fa5 100644
--- a/drivers/media/usb/dvb-usb/cxusb.c
+++ b/drivers/media/usb/dvb-usb/cxusb.c
@@ -68,7 +68,7 @@ static int cxusb_ctrl_msg(struct dvb_usb_device *d,
 
 	wo = (rbuf == NULL || rlen == 0); /* write-only */
 
-	mutex_lock(&st->data_mutex);
+	mutex_lock(&d->data_mutex);
 	st->data[0] = cmd;
 	memcpy(&st->data[1], wbuf, wlen);
 	if (wo)
@@ -77,7 +77,7 @@ static int cxusb_ctrl_msg(struct dvb_usb_device *d,
 		ret = dvb_usb_generic_rw(d, st->data, 1 + wlen,
 					 rbuf, rlen, 0);
 
-	mutex_unlock(&st->data_mutex);
+	mutex_unlock(&d->data_mutex);
 	return ret;
 }
 
@@ -1461,43 +1461,36 @@ static struct dvb_usb_device_properties cxusb_mygica_t230_properties;
 static int cxusb_probe(struct usb_interface *intf,
 		       const struct usb_device_id *id)
 {
-	struct dvb_usb_device *d;
-	struct cxusb_state *st;
-
 	if (0 == dvb_usb_device_init(intf, &cxusb_medion_properties,
-				     THIS_MODULE, &d, adapter_nr) ||
+				     THIS_MODULE, NULL, adapter_nr) ||
 	    0 == dvb_usb_device_init(intf, &cxusb_bluebird_lgh064f_properties,
-				     THIS_MODULE, &d, adapter_nr) ||
+				     THIS_MODULE, NULL, adapter_nr) ||
 	    0 == dvb_usb_device_init(intf, &cxusb_bluebird_dee1601_properties,
-				     THIS_MODULE, &d, adapter_nr) ||
+				     THIS_MODULE, NULL, adapter_nr) ||
 	    0 == dvb_usb_device_init(intf, &cxusb_bluebird_lgz201_properties,
-				     THIS_MODULE, &d, adapter_nr) ||
+				     THIS_MODULE, NULL, adapter_nr) ||
 	    0 == dvb_usb_device_init(intf, &cxusb_bluebird_dtt7579_properties,
-				     THIS_MODULE, &d, adapter_nr) ||
+				     THIS_MODULE, NULL, adapter_nr) ||
 	    0 == dvb_usb_device_init(intf, &cxusb_bluebird_dualdig4_properties,
-				     THIS_MODULE, &d, adapter_nr) ||
+				     THIS_MODULE, NULL, adapter_nr) ||
 	    0 == dvb_usb_device_init(intf, &cxusb_bluebird_nano2_properties,
-				     THIS_MODULE, &d, adapter_nr) ||
+				     THIS_MODULE, NULL, adapter_nr) ||
 	    0 == dvb_usb_device_init(intf,
 				&cxusb_bluebird_nano2_needsfirmware_properties,
-				     THIS_MODULE, &d, adapter_nr) ||
+				     THIS_MODULE, NULL, adapter_nr) ||
 	    0 == dvb_usb_device_init(intf, &cxusb_aver_a868r_properties,
-				     THIS_MODULE, &d, adapter_nr) ||
+				     THIS_MODULE, NULL, adapter_nr) ||
 	    0 == dvb_usb_device_init(intf,
 				     &cxusb_bluebird_dualdig4_rev2_properties,
-				     THIS_MODULE, &d, adapter_nr) ||
+				     THIS_MODULE, NULL, adapter_nr) ||
 	    0 == dvb_usb_device_init(intf, &cxusb_d680_dmb_properties,
-				     THIS_MODULE, &d, adapter_nr) ||
+				     THIS_MODULE, NULL, adapter_nr) ||
 	    0 == dvb_usb_device_init(intf, &cxusb_mygica_d689_properties,
-				     THIS_MODULE, &d, adapter_nr) ||
+				     THIS_MODULE, NULL, adapter_nr) ||
 	    0 == dvb_usb_device_init(intf, &cxusb_mygica_t230_properties,
-				     THIS_MODULE, &d, adapter_nr) ||
-	    0) {
-		st = d->priv;
-		mutex_init(&st->data_mutex);
-
+				     THIS_MODULE, NULL, adapter_nr) ||
+	    0)
 		return 0;
-	}
 
 	return -EINVAL;
 }