[PATCH 5.7 01/14] media: dvbdev: Fix tuner->demod media controller link

From: Greg Kroah-Hartman
Date: Fri Jun 05 2020 - 10:15:49 EST

From: Brad Love <brad@xxxxxxxxxxxxxxxx>

commit 9f984cacf4f4d53fd8a3f44d7f13528b81c1f6a8 upstream.

Fixes bug exposed by:

[a3fbc2e6bb0: media: mc-entity.c: use WARN_ON, validate link pads]

The dvbdev incorrectly requests a tuner sink pad to connect to a demux
sink pad. The media controller failure percolates back and the dvb device
creation fails. Fix this by requesting a tuner source pad. Instead of
forcing that pad to be index zero, check if a negative integer error
is returned. A note is added that first source pad found is chosen.

Affected bridges cx231xx and em28xx printed the below warning[s]
when a variety of media controller dvb enabled devices were connected.
The warning returns an error causing all affected devices to fail DVB
device creation.

[ 253.138332] ------------[ cut here ]------------
[ 253.138339] WARNING: CPU: 0 PID: 1550 at drivers/media/mc/mc-entity.c:669 media_create_pad_link+0x1e0/0x200 [mc]
[ 253.138339] Modules linked in: si2168 em28xx_dvb(+) em28xx si2157 lgdt3306a cx231xx_dvb dvb_core cx231xx_alsa cx25840 cx231xx tveeprom cx2341x i2c_mux videobuf2_vmalloc videobuf2_memops videobuf2_v4l2 videobuf2_common videodev mc ir_rc5_decoder rc_hauppauge mceusb rc_core eda
c_mce_amd kvm nls_iso8859_1 crct10dif_pclmul crc32_pclmul ghash_clmulni_intel aesni_intel crypto_simd cryptd glue_helper efi_pstore wmi_bmof k10temp asix usbnet mii nouveau snd_hda_codec_realtek snd_hda_codec_generic input_leds ledtrig_audio snd_hda_codec_hdmi mxm_wmi snd_hda_in
tel video snd_intel_dspcfg ttm snd_hda_codec drm_kms_helper snd_hda_core drm snd_hwdep snd_seq_midi snd_seq_midi_event i2c_algo_bit snd_pcm snd_rawmidi fb_sys_fops snd_seq syscopyarea sysfillrect snd_seq_device sysimgblt snd_timer snd soundcore ccp mac_hid sch_fq_codel parport_p
c ppdev lp parport ip_tables x_tables autofs4 vfio_pci irqbypass vfio_virqfd vfio_iommu_type1 vfio hid_generic usbhid hid i2c_piix4 ahci libahci wmi gpio_amdpt
[ 253.138370] gpio_generic
[ 253.138372] CPU: 0 PID: 1550 Comm: modprobe Tainted: G W 5.7.0-rc2+ #181
[ 253.138373] Hardware name: MSI MS-7A39/B350M GAMING PRO (MS-7A39), BIOS 2.G0 04/27/2018
[ 253.138376] RIP: 0010:media_create_pad_link+0x1e0/0x200 [mc]
[ 253.138378] Code: 26 fd ff ff 44 8b 4d d0 eb d9 0f 0b 41 b9 ea ff ff ff 44 89 c8 c3 0f 0b 41 b9 ea ff ff ff eb f2 0f 0b 41 b9 ea ff ff ff eb e8 <0f> 0b 41 b9 ea ff ff ff eb af 0f 0b 41 b9 ea ff ff ff eb a5 66 90
[ 253.138379] RSP: 0018:ffffb9ecc0ee7a78 EFLAGS: 00010246
[ 253.138380] RAX: ffff943f706c99d8 RBX: 0000000000000000 RCX: 0000000000000000
[ 253.138381] RDX: ffff943f613e0180 RSI: 0000000000000000 RDI: ffff943f706c9958
[ 253.138381] RBP: ffffb9ecc0ee7ab0 R08: 0000000000000001 R09: ffff943f613e0180
[ 253.138382] R10: ffff943f613e0180 R11: ffff943f706c9400 R12: 0000000000000000
[ 253.138383] R13: 0000000000000001 R14: ffff943f706c9958 R15: 0000000000000001
[ 253.138384] FS: 00007f3cd29ba540(0000) GS:ffff943f8ec00000(0000) knlGS:0000000000000000
[ 253.138385] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 253.138385] CR2: 000055f7de0ca830 CR3: 00000003dd208000 CR4: 00000000003406f0
[ 253.138386] Call Trace:
[ 253.138392] media_create_pad_links+0x104/0x1b0 [mc]
[ 253.138397] dvb_create_media_graph+0x350/0x5f0 [dvb_core]
[ 253.138402] em28xx_dvb_init+0x5ea/0x2600 [em28xx_dvb]
[ 253.138408] em28xx_register_extension+0x63/0xc0 [em28xx]
[ 253.138410] ? 0xffffffffc039c000
[ 253.138412] em28xx_dvb_register+0x15/0x1000 [em28xx_dvb]
[ 253.138416] do_one_initcall+0x71/0x250
[ 253.138418] ? do_init_module+0x27/0x22e
[ 253.138421] ? _cond_resched+0x1a/0x50
[ 253.138423] ? kmem_cache_alloc_trace+0x1ec/0x270
[ 253.138425] ? __vunmap+0x1e3/0x240
[ 253.138427] do_init_module+0x5f/0x22e
[ 253.138430] load_module+0x2525/0x2d40
[ 253.138436] __do_sys_finit_module+0xe5/0x120
[ 253.138438] ? __do_sys_finit_module+0xe5/0x120
[ 253.138442] __x64_sys_finit_module+0x1a/0x20
[ 253.138443] do_syscall_64+0x57/0x1b0
[ 253.138445] entry_SYSCALL_64_after_hwframe+0x44/0xa9
[ 253.138446] RIP: 0033:0x7f3cd24dc839
[ 253.138448] Code: 00 f3 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 1f f6 2c 00 f7 d8 64 89 01 48
[ 253.138449] RSP: 002b:00007ffe4fc514d8 EFLAGS: 00000246 ORIG_RAX: 0000000000000139
[ 253.138450] RAX: ffffffffffffffda RBX: 000055a9237f63f0 RCX: 00007f3cd24dc839
[ 253.138451] RDX: 0000000000000000 RSI: 000055a922c3ad2e RDI: 0000000000000000
[ 253.138451] RBP: 000055a922c3ad2e R08: 0000000000000000 R09: 0000000000000000
[ 253.138452] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
[ 253.138453] R13: 000055a9237f5550 R14: 0000000000040000 R15: 000055a9237f63f0
[ 253.138456] ---[ end trace a60f19c54aa96ec4 ]---

[ 234.915628] ------------[ cut here ]------------
[ 234.915640] WARNING: CPU: 0 PID: 1502 at drivers/media/mc/mc-entity.c:669 media_create_pad_link+0x1e0/0x200 [mc]
[ 234.915641] Modules linked in: si2157 lgdt3306a cx231xx_dvb(+) dvb_core cx231xx_alsa cx25840 cx231xx tveeprom cx2341x i2c_mux videobuf2_vmalloc videobuf2_memops videobuf2_v4l2 videobuf2_common videodev mc ir_rc5_decoder rc_hauppauge mceusb rc_core edac_mce_amd kvm nls_iso8859
_1 crct10dif_pclmul crc32_pclmul ghash_clmulni_intel aesni_intel crypto_simd cryptd glue_helper efi_pstore wmi_bmof k10temp asix usbnet mii nouveau snd_hda_codec_realtek snd_hda_codec_generic input_leds ledtrig_audio snd_hda_codec_hdmi mxm_wmi snd_hda_intel video snd_intel_dspcf
g ttm snd_hda_codec drm_kms_helper snd_hda_core drm snd_hwdep snd_seq_midi snd_seq_midi_event i2c_algo_bit snd_pcm snd_rawmidi fb_sys_fops snd_seq syscopyarea sysfillrect snd_seq_device sysimgblt snd_timer snd soundcore ccp mac_hid sch_fq_codel parport_pc ppdev lp parport ip_tab
les x_tables autofs4 vfio_pci irqbypass vfio_virqfd vfio_iommu_type1 vfio hid_generic usbhid hid i2c_piix4 ahci libahci wmi gpio_amdpt gpio_generic
[ 234.915700] CPU: 0 PID: 1502 Comm: modprobe Not tainted 5.7.0-rc2+ #181
[ 234.915702] Hardware name: MSI MS-7A39/B350M GAMING PRO (MS-7A39), BIOS 2.G0 04/27/2018
[ 234.915709] RIP: 0010:media_create_pad_link+0x1e0/0x200 [mc]
[ 234.915712] Code: 26 fd ff ff 44 8b 4d d0 eb d9 0f 0b 41 b9 ea ff ff ff 44 89 c8 c3 0f 0b 41 b9 ea ff ff ff eb f2 0f 0b 41 b9 ea ff ff ff eb e8 <0f> 0b 41 b9 ea ff ff ff eb af 0f 0b 41 b9 ea ff ff ff eb a5 66 90
[ 234.915714] RSP: 0018:ffffb9ecc1b6fa50 EFLAGS: 00010246
[ 234.915717] RAX: ffff943f8c94a9d8 RBX: 0000000000000000 RCX: 0000000000000000
[ 234.915719] RDX: ffff943f613e0900 RSI: 0000000000000000 RDI: ffff943f8c94a958
[ 234.915721] RBP: ffffb9ecc1b6fa88 R08: 0000000000000001 R09: ffff943f613e0900
[ 234.915723] R10: ffff943f613e0900 R11: ffff943f6b590c00 R12: 0000000000000000
[ 234.915724] R13: 0000000000000001 R14: ffff943f8c94a958 R15: 0000000000000001
[ 234.915727] FS: 00007f4ca3646540(0000) GS:ffff943f8ec00000(0000) knlGS:0000000000000000
[ 234.915729] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 234.915731] CR2: 00007fff7a53ba18 CR3: 00000003da614000 CR4: 00000000003406f0
[ 234.915733] Call Trace:
[ 234.915745] media_create_pad_links+0x104/0x1b0 [mc]
[ 234.915756] dvb_create_media_graph+0x350/0x5f0 [dvb_core]
[ 234.915766] dvb_init.part.4+0x691/0x1360 [cx231xx_dvb]
[ 234.915780] dvb_init+0x1a/0x20 [cx231xx_dvb]
[ 234.915787] cx231xx_register_extension+0x71/0xa0 [cx231xx]
[ 234.915791] ? 0xffffffffc042f000
[ 234.915796] cx231xx_dvb_register+0x15/0x1000 [cx231xx_dvb]
[ 234.915802] do_one_initcall+0x71/0x250
[ 234.915807] ? do_init_module+0x27/0x22e
[ 234.915811] ? _cond_resched+0x1a/0x50
[ 234.915816] ? kmem_cache_alloc_trace+0x1ec/0x270
[ 234.915820] ? __vunmap+0x1e3/0x240
[ 234.915826] do_init_module+0x5f/0x22e
[ 234.915831] load_module+0x2525/0x2d40
[ 234.915848] __do_sys_finit_module+0xe5/0x120
[ 234.915850] ? __do_sys_finit_module+0xe5/0x120
[ 234.915862] __x64_sys_finit_module+0x1a/0x20
[ 234.915865] do_syscall_64+0x57/0x1b0
[ 234.915870] entry_SYSCALL_64_after_hwframe+0x44/0xa9
[ 234.915872] RIP: 0033:0x7f4ca3168839
[ 234.915876] Code: 00 f3 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 1f f6 2c 00 f7 d8 64 89 01 48
[ 234.915878] RSP: 002b:00007ffcea3db3b8 EFLAGS: 00000246 ORIG_RAX: 0000000000000139
[ 234.915881] RAX: ffffffffffffffda RBX: 000055af22c29340 RCX: 00007f4ca3168839
[ 234.915882] RDX: 0000000000000000 RSI: 000055af22c38390 RDI: 0000000000000001
[ 234.915884] RBP: 000055af22c38390 R08: 0000000000000000 R09: 0000000000000000
[ 234.915885] R10: 0000000000000001 R11: 0000000000000246 R12: 0000000000000000
[ 234.915887] R13: 000055af22c29060 R14: 0000000000040000 R15: 0000000000000000
[ 234.915896] ---[ end trace a60f19c54aa96ec3 ]---

Signed-off-by: Brad Love <brad@xxxxxxxxxxxxxxxx>
Reviewed-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
Signed-off-by: Sean Young <sean@xxxxxxxx>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
drivers/media/dvb-core/dvbdev.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

--- a/drivers/media/dvb-core/dvbdev.c
+++ b/drivers/media/dvb-core/dvbdev.c
@@ -707,9 +707,10 @@ int dvb_create_media_graph(struct dvb_ad
}

if (ntuner && ndemod) {
- pad_source = media_get_pad_index(tuner, true,
+ /* NOTE: first found tuner source pad presumed correct */
+ pad_source = media_get_pad_index(tuner, false,
PAD_SIGNAL_ANALOG);
- if (pad_source)
+ if (pad_source < 0)
return -EINVAL;
ret = media_create_pad_links(mdev,
MEDIA_ENT_F_TUNER,