V4L/DVB (10229): cx88-dvb: Fix order of frontend allocations

On Fri, 2009-01-09 at 15:40 +0300, Goga777 wrote:
> hI
>
> With today v4l-dvb I couldn't run my hvr4000 card on 2.6.27 kernel

> [   14.555162] cx88/2: cx2388x dvb driver version 0.0.6 loaded
> [   14.555231] cx88/2: registering cx8802 driver, type: dvb access: shared
> [   14.555303] cx88[0]/2: subsystem: 0070:6900, board: Hauppauge WinTV-HVR4000 DVB-S/S2/T/Hybrid [card=68]
> [   14.555374] cx88[0]/2: cx2388x based DVB/ATSC card
> [   14.555446] BUG: unable to handle kernel NULL pointer dereference at 00000000
> [   14.555560] IP: [<c02e6bff>] __mutex_lock_common+0x3c/0xe4
> [   14.555652] *pde = 00000000
> [   14.555735] Oops: 0002 [#1] SMP
> [   14.555851] Modules linked in: cx88_dvb(+) cx88_vp3054_i2c videobuf_dvb wm8775 dvb_core tuner_simple tuner_types snd_seq_dummy tda9887 snd_seq_oss(+) snd_intel8x0(+) tda8290 snd_seq_midi snd_seq_midi_event snd_ac97_codec cx88_alsa(+) snd_seq ac97_bus snd_pcm_oss snd_mixer_oss snd_pcm snd_rawmidi snd_timer tuner snd_seq_device psmouse snd serio_raw ivtv(+) cx8800 cx8802 cx88xx soundcore cx2341x ir_common ns558 i2c_i801 v4l2_common videodev i2c_algo_bit gameport v4l1_compat snd_page_alloc tveeprom pcspkr floppy videobuf_dma_sg videobuf_core btcx_risc i2c_core parport_pc parport button intel_agp agpgart shpchp pci_hotplug rng_core iTCO_wdt sd_mod evdev usbhid hid ff_memless ext3 jbd mbcache ide_cd_mod cdrom ide_disk ata_piix libata dock 8139too usb_storage scsi_mod piix 8139cp mii ide_core uhci_hcd ehci_hcd usbcore thermal processor fan thermal_sys
> [   14.557013]
> [   14.557013] Pid: 2310, comm: modprobe Not tainted (2.6.27.1-custom-default1 #1)
> [   14.557013] EIP: 0060:[<c02e6bff>] EFLAGS: 00010246 CPU: 1
> [   14.557013] EIP is at __mutex_lock_common+0x3c/0xe4
> [   14.557013] EAX: de653e98 EBX: de739118 ECX: de739120 EDX: 00000000
> [   14.557013] ESI: dd4209e0 EDI: de73911c EBP: de653eb0 ESP: de653e88
> [   14.557013]  DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068
> [   14.557013] Process modprobe (pid: 2310, ti=de652000 task=dd4209e0 task.ti=de652000)
> [   14.557013] Stack: 3535352e 5d343733 00000002 de739120 de739120 00000000 c044a6c0 de739110
> [   14.557013]        de739118 00000001 de653ebc c02e6d38 c02e6b88 de653ec4 c02e6b88 de653ed8
> [   14.557013]        e1ac7115 de6a9000 00000001 00000000 de653f0c e1aeca62 de739004 de739000
> [   14.557013] Call Trace:
> [   14.557013]  [<c02e6d38>] ? __mutex_lock_slowpath+0x17/0x1a
> [   14.557013]  [<c02e6b88>] ? mutex_lock+0x12/0x14
> [   14.557013]  [<c02e6b88>] ? mutex_lock+0x12/0x14
> [   14.557013]  [<e1ac7115>] ? videobuf_dvb_get_frontend+0x19/0x40 [videobuf_dvb]
> [   14.557013]  [<e1aeca62>] ? cx8802_dvb_probe+0xc9/0x1945 [cx88_dvb]
> [   14.557013]  [<e09ee41e>] ? cx8802_register_driver+0xbd/0x1ac [cx8802]
> [   14.557013]  [<e09ee467>] ? cx8802_register_driver+0x106/0x1ac [cx8802]
> [   14.557013]  [<e1aee37f>] ? dvb_init+0x22/0x27 [cx88_dvb]
> [   14.557013]  [<c0101132>] ? _stext+0x42/0x11a
> [   14.557013]  [<e1aee35d>] ? dvb_init+0x0/0x27 [cx88_dvb]
> [   14.557013]  [<c013d2ca>] ? __blocking_notifier_call_chain+0xe/0x51
> [   14.557013]  [<c014970b>] ? sys_init_module+0x8c/0x17d
> [   14.557013]  [<c0103b42>] ? syscall_call+0x7/0xb
> [   14.557013]  [<c013007b>] ? round_jiffies_relative+0x14/0x16
> [   14.557013]  =======================
> [   14.557013] Code: 78 04 89 f8 89 55 e0 64 8b 35 00 30 3f c0 e8 2e 0c 00 00 8d 43 08 89 45 e4 8b 53 0c 8d 45 e8 8b 4d e4 89 43 0c 89 4d e8 89 55 ec <89> 02 89 75 f0 83 c8 ff 87 03 48 74 55 8a 45 e0 8b 4d e0 83 e0
> [   14.557013] EIP: [<c02e6bff>] __mutex_lock_common+0x3c/0xe4 SS:ESP 0068:de653e88
> [   14.565211] ---[ end trace 94d8b014e067ac7b ]---

Tested and confirmed to work by several users at linux-media@vger.kernel.org
Signed-off-by: Andy Walls <awalls@radix.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/video/cx88/cx88-dvb.c

@@ -614,34 +614,41 @@ static struct stv0288_config tevii_tuner_earda_config = {
 	.set_ts_params = cx24116_set_ts_param,
 };
 
-static int dvb_register(struct cx8802_dev *dev)
+static int cx8802_alloc_frontends(struct cx8802_dev *dev)
 {
 	struct cx88_core *core = dev->core;
-	struct videobuf_dvb_frontend *fe0, *fe1 = NULL;
-	int mfe_shared = 0; /* bus not shared by default */
+	struct videobuf_dvb_frontend *fe = NULL;
 	int i;
 
-	if (0 != core->i2c_rc) {
-		printk(KERN_ERR "%s/2: no i2c-bus available, cannot attach dvb drivers\n", core->name);
-		goto frontend_detach;
-	}
-
-	if (!core->board.num_frontends)
-		return -EINVAL;
-
 	mutex_init(&dev->frontends.lock);
 	INIT_LIST_HEAD(&dev->frontends.felist);
 
+	if (!core->board.num_frontends)
+		return -ENODEV;
+
 	printk(KERN_INFO "%s() allocating %d frontend(s)\n", __func__,
 			 core->board.num_frontends);
 	for (i = 1; i <= core->board.num_frontends; i++) {
-		fe0 = videobuf_dvb_alloc_frontend(&dev->frontends, i);
-		if (!fe0) {
+		fe = videobuf_dvb_alloc_frontend(&dev->frontends, i);
+		if (!fe) {
 			printk(KERN_ERR "%s() failed to alloc\n", __func__);
 			videobuf_dvb_dealloc_frontends(&dev->frontends);
-			goto frontend_detach;
+			return -ENOMEM;
 		}
 	}
+	return 0;
+}
+
+static int dvb_register(struct cx8802_dev *dev)
+{
+	struct cx88_core *core = dev->core;
+	struct videobuf_dvb_frontend *fe0, *fe1 = NULL;
+	int mfe_shared = 0; /* bus not shared by default */
+
+	if (0 != core->i2c_rc) {
+		printk(KERN_ERR "%s/2: no i2c-bus available, cannot attach dvb drivers\n", core->name);
+		goto frontend_detach;
+	}
 
 	/* Get the first frontend */
 	fe0 = videobuf_dvb_get_frontend(&dev->frontends, 1);
@@ -1243,6 +1250,8 @@ static int cx8802_dvb_probe(struct cx8802_driver *drv)
 	struct cx88_core *core = drv->core;
 	struct cx8802_dev *dev = drv->core->dvbdev;
 	int err;
+	struct videobuf_dvb_frontend *fe;
+	int i;
 
 	dprintk( 1, "%s\n", __func__);
 	dprintk( 1, " ->being probed by Card=%d Name=%s, PCI %02x:%02x\n",
@@ -1258,17 +1267,17 @@ static int cx8802_dvb_probe(struct cx8802_driver *drv)
 	/* If vp3054 isn't enabled, a stub will just return 0 */
 	err = vp3054_i2c_probe(dev);
 	if (0 != err)
-		goto fail_probe;
+		goto fail_core;
 
 	/* dvb stuff */
 	printk(KERN_INFO "%s/2: cx2388x based DVB/ATSC card\n", core->name);
 	dev->ts_gen_cntrl = 0x0c;
 
-	err = -ENODEV;
-	if (core->board.num_frontends) {
-		struct videobuf_dvb_frontend *fe;
-		int i;
+	err = cx8802_alloc_frontends(dev);
+	if (err)
+		goto fail_core;
 
+	err = -ENODEV;
 	for (i = 1; i <= core->board.num_frontends; i++) {
 		fe = videobuf_dvb_get_frontend(&core->dvbdev->frontends, i);
 		if (fe == NULL) {
@@ -1285,12 +1294,7 @@ static int cx8802_dvb_probe(struct cx8802_driver *drv)
 		/* init struct videobuf_dvb */
 		fe->dvb.name = dev->core->name;
 	}
-	} else {
-		/* no frontends allocated */
-		printk(KERN_ERR "%s/2 .num_frontends should be non-zero\n",
-			core->name);
-		goto fail_core;
-	}
+
 	err = dvb_register(dev);
 	if (err)
 		/* frontends/adapter de-allocated in dvb_register */