linux-stable.git/drivers, branch v3.16.66 Linux kernel stable tree tty: mark Siemens R3964 line discipline as BROKEN 2019-05-02T20:42:07+00:00 Greg Kroah-Hartman gregkh@linuxfoundation.org 2019-04-05T13:39:26+00:00 e0d2ad5eaec135bb79a7045b1c0718557bac4c4d commit c7084edc3f6d67750f50d4183134c4fb5712a5c8 upstream. The n_r3964 line discipline driver was written in a different time, when SMP machines were rare, and users were trusted to do the right thing. Since then, the world has moved on but not this code, it has stayed rooted in the past with its lovely hand-crafted list structures and loads of "interesting" race conditions all over the place. After attempting to clean up most of the issues, I just gave up and am now marking the driver as BROKEN so that hopefully someone who has this hardware will show up out of the woodwork (I know you are out there!) and will help with debugging a raft of changes that I had laying around for the code, but was too afraid to commit as odds are they would break things. Many thanks to Jann and Linus for pointing out the initial problems in this codebase, as well as many reviews of my attempts to fix the issues. It was a case of whack-a-mole, and as you can see, the mole won. Reported-by: Jann Horn <jannh@google.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Ben Hutchings <ben@decadent.org.uk> 
commit c7084edc3f6d67750f50d4183134c4fb5712a5c8 upstream.

The n_r3964 line discipline driver was written in a different time, when
SMP machines were rare, and users were trusted to do the right thing.
Since then, the world has moved on but not this code, it has stayed
rooted in the past with its lovely hand-crafted list structures and
loads of "interesting" race conditions all over the place.

After attempting to clean up most of the issues, I just gave up and am
now marking the driver as BROKEN so that hopefully someone who has this
hardware will show up out of the woodwork (I know you are out there!)
and will help with debugging a raft of changes that I had laying around
for the code, but was too afraid to commit as odds are they would break
things.

Many thanks to Jann and Linus for pointing out the initial problems in
this codebase, as well as many reviews of my attempts to fix the issues.
It was a case of whack-a-mole, and as you can see, the mole won.

Reported-by: Jann Horn <jannh@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
brcmfmac: add subtype check for event handling in data path 2019-05-02T20:42:06+00:00 Arend van Spriel arend.vanspriel@broadcom.com 2019-02-14T12:43:48+00:00 52b1af5e74cc3f4d513eacf49f71d9855a9ccbec commit a4176ec356c73a46c07c181c6d04039fafa34a9f upstream. For USB there is no separate channel being used to pass events from firmware to the host driver and as such are passed over the data path. In order to detect mock event messages an additional check is needed on event subtype. This check is added conditionally using unlikely() keyword. Reviewed-by: Hante Meuleman <hante.meuleman@broadcom.com> Reviewed-by: Pieter-Paul Giesberts <pieter-paul.giesberts@broadcom.com> Reviewed-by: Franky Lin <franky.lin@broadcom.com> Signed-off-by: Arend van Spriel <arend.vanspriel@broadcom.com> Signed-off-by: Kalle Valo <kvalo@codeaurora.org> [bwh: Backported to 3.16: - Drop changes to PCIe bus support - Adjust filenames] Signed-off-by: Ben Hutchings <ben@decadent.org.uk> 
commit a4176ec356c73a46c07c181c6d04039fafa34a9f upstream.

For USB there is no separate channel being used to pass events
from firmware to the host driver and as such are passed over the
data path. In order to detect mock event messages an additional
check is needed on event subtype. This check is added conditionally
using unlikely() keyword.

Reviewed-by: Hante Meuleman <hante.meuleman@broadcom.com>
Reviewed-by: Pieter-Paul Giesberts <pieter-paul.giesberts@broadcom.com>
Reviewed-by: Franky Lin <franky.lin@broadcom.com>
Signed-off-by: Arend van Spriel <arend.vanspriel@broadcom.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
[bwh: Backported to 3.16:
 - Drop changes to PCIe bus support
 - Adjust filenames]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
brcmfmac: revise handling events in receive path 2019-05-02T20:42:06+00:00 Arend van Spriel arend@broadcom.com 2016-04-11T09:35:27+00:00 91d35844e9d7b8efead7555f75eb1380c1e706b8 commit 9c349892ccc90c6de2baaa69cc78449f58082273 upstream. Move event handling out of brcmf_netif_rx() avoiding the need to pass a flag. This flag is only ever true for USB hosts as other interface use separate brcmf_rx_event() function. Reviewed-by: Hante Meuleman <hante.meuleman@broadcom.com> Reviewed-by: Pieter-Paul Giesberts <pieter-paul.giesberts@broadcom.com> Reviewed-by: Franky Lin <franky.lin@broadcom.com> Signed-off-by: Arend van Spriel <arend@broadcom.com> Signed-off-by: Kalle Valo <kvalo@codeaurora.org> [bwh: Backported to 3.16 as dependency of commit a4176ec356c7 "brcmfmac: add subtype check for event handling in data path" - Drop changes to PCIe bus support - Adjust filenames] Signed-off-by: Ben Hutchings <ben@decadent.org.uk> 
commit 9c349892ccc90c6de2baaa69cc78449f58082273 upstream.

Move event handling out of brcmf_netif_rx() avoiding the need
to pass a flag. This flag is only ever true for USB hosts as
other interface use separate brcmf_rx_event() function.

Reviewed-by: Hante Meuleman <hante.meuleman@broadcom.com>
Reviewed-by: Pieter-Paul Giesberts <pieter-paul.giesberts@broadcom.com>
Reviewed-by: Franky Lin <franky.lin@broadcom.com>
Signed-off-by: Arend van Spriel <arend@broadcom.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
[bwh: Backported to 3.16 as dependency of commit a4176ec356c7
 "brcmfmac: add subtype check for event handling in data path"
 - Drop changes to PCIe bus support
 - Adjust filenames]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
brcmfmac: fix incorrect event channel deduction 2019-05-02T20:42:05+00:00 Gavin Li git@thegavinli.com 2017-01-17T23:24:05+00:00 076a3985234a4978cc6935a9e530942b8ee50062 commit 8e290cecdd0178f3d4cf7d463c51dc7e462843b4 upstream. brcmf_sdio_fromevntchan() was being called on the the data frame rather than the software header, causing some frames to be mischaracterized as on the event channel rather than the data channel. This fixes a major performance regression (due to dropped packets). With this patch the download speed jumped from 1Mbit/s back up to 40MBit/s due to the sheer amount of packets being incorrectly processed. Fixes: c56caa9db8ab ("brcmfmac: screening firmware event packet") Signed-off-by: Gavin Li <git@thegavinli.com> Acked-by: Arend van Spriel <arend.vanspriel@broadcom.com> [kvalo@codeaurora.org: improve commit logs based on email discussion] Signed-off-by: Kalle Valo <kvalo@codeaurora.org> [bwh: Backported to 3.16: adjust filename] Signed-off-by: Ben Hutchings <ben@decadent.org.uk> 
commit 8e290cecdd0178f3d4cf7d463c51dc7e462843b4 upstream.

brcmf_sdio_fromevntchan() was being called on the the data frame
rather than the software header, causing some frames to be
mischaracterized as on the event channel rather than the data channel.

This fixes a major performance regression (due to dropped packets). With
this patch the download speed jumped from 1Mbit/s back up to 40MBit/s due
to the sheer amount of packets being incorrectly processed.

Fixes: c56caa9db8ab ("brcmfmac: screening firmware event packet")
Signed-off-by: Gavin Li <git@thegavinli.com>
Acked-by: Arend van Spriel <arend.vanspriel@broadcom.com>
[kvalo@codeaurora.org: improve commit logs based on email discussion]
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
[bwh: Backported to 3.16: adjust filename]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
brcmfmac: screening firmware event packet 2019-05-02T20:42:05+00:00 Franky Lin franky.lin@broadcom.com 2016-04-11T09:35:25+00:00 2e50667aef7a00ff71d304776e7af287272a15cf commit c56caa9db8abbbfb9e31325e0897705aa897db37 upstream. Firmware uses asynchronized events as a communication method to the host. The event packets are marked as ETH_P_LINK_CTL protocol type. For SDIO and PCIe bus, this kind of packets are delivered through virtual event channel not data channel. This patch adds a screening logic to make sure the event handler only processes the events coming from the correct channel. Reviewed-by: Pieter-Paul Giesberts <pieter-paul.giesberts@broadcom.com> Signed-off-by: Franky Lin <franky.lin@broadcom.com> Signed-off-by: Arend van Spriel <arend@broadcom.com> Signed-off-by: Kalle Valo <kvalo@codeaurora.org> [bwh: Backported to 3.16: - Drop changes to PCIe bus support - Adjust filenames] Signed-off-by: Ben Hutchings <ben@decadent.org.uk> 
commit c56caa9db8abbbfb9e31325e0897705aa897db37 upstream.

Firmware uses asynchronized events as a communication method to the
host. The event packets are marked as ETH_P_LINK_CTL protocol type. For
SDIO and PCIe bus, this kind of packets are delivered through virtual
event channel not data channel. This patch adds a screening logic to
make sure the event handler only processes the events coming from the
correct channel.

Reviewed-by: Pieter-Paul Giesberts <pieter-paul.giesberts@broadcom.com>
Signed-off-by: Franky Lin <franky.lin@broadcom.com>
Signed-off-by: Arend van Spriel <arend@broadcom.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
[bwh: Backported to 3.16:
 - Drop changes to PCIe bus support
 - Adjust filenames]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
brcmfmac: make brcmf_proto_hdrpull() return struct brcmf_if instance 2019-05-02T20:42:05+00:00 Arend van Spriel arend@broadcom.com 2015-08-26T20:14:54+00:00 d0e1072f9ef8ccfba25cee14bc1d4006ee90c208 commit 796cfb65e3ed01a9b08e3a0b93e34120c54bbbd2 upstream. Avoid spreading the ifidx in the driver, but have it return the struct brcmf_if instance. Reviewed-by: Hante Meuleman <meuleman@broadcom.com> Reviewed-by: Franky (Zhenhui) Lin <frankyl@broadcom.com> Reviewed-by: Pieter-Paul Giesberts <pieterpg@broadcom.com> Signed-off-by: Arend van Spriel <arend@broadcom.com> Signed-off-by: Kalle Valo <kvalo@codeaurora.org> [bwh: Backported to 3.16: - Drop changes to PCIe bus support - Adjust filenames] Signed-off-by: Ben Hutchings <ben@decadent.org.uk> 
commit 796cfb65e3ed01a9b08e3a0b93e34120c54bbbd2 upstream.

Avoid spreading the ifidx in the driver, but have it return the
struct brcmf_if instance.

Reviewed-by: Hante Meuleman <meuleman@broadcom.com>
Reviewed-by: Franky (Zhenhui) Lin <frankyl@broadcom.com>
Reviewed-by: Pieter-Paul Giesberts <pieterpg@broadcom.com>
Signed-off-by: Arend van Spriel <arend@broadcom.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
[bwh: Backported to 3.16:
 - Drop changes to PCIe bus support
 - Adjust filenames]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
brcmfmac: consolidate ifp lookup in driver core 2019-05-02T20:42:05+00:00 Arend van Spriel arend@broadcom.com 2015-08-26T20:14:53+00:00 9c4031ec83b8f68353dee6181a76ae64642a75c0 commit 75effb03ee8e4c9d4bbc909118ce5444b047dfde upstream. In rx path the firmware provide an interface index which is used to map to a struct brcmf_if instance. However, this involves some trick that is done in two places. This is changed by having driver core providing brcmf_get_ifp() function. Reviewed-by: Hante Meuleman <meuleman@broadcom.com> Reviewed-by: Franky (Zhenhui) Lin <frankyl@broadcom.com> Reviewed-by: Pieter-Paul Giesberts <pieterpg@broadcom.com> Signed-off-by: Arend van Spriel <arend@broadcom.com> Signed-off-by: Kalle Valo <kvalo@codeaurora.org> [bwh: Backported to 3.16: - Drop changes to PCIe bus support - Adjust filenames] Signed-off-by: Ben Hutchings <ben@decadent.org.uk> 
commit 75effb03ee8e4c9d4bbc909118ce5444b047dfde upstream.

In rx path the firmware provide an interface index which is used to
map to a struct brcmf_if instance. However, this involves some trick
that is done in two places. This is changed by having driver core
providing brcmf_get_ifp() function.

Reviewed-by: Hante Meuleman <meuleman@broadcom.com>
Reviewed-by: Franky (Zhenhui) Lin <frankyl@broadcom.com>
Reviewed-by: Pieter-Paul Giesberts <pieterpg@broadcom.com>
Signed-off-by: Arend van Spriel <arend@broadcom.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
[bwh: Backported to 3.16:
 - Drop changes to PCIe bus support
 - Adjust filenames]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
brcmfmac: assure SSID length from firmware is limited 2019-05-02T20:42:04+00:00 Arend van Spriel arend.vanspriel@broadcom.com 2019-02-14T12:43:47+00:00 9657f3abd17772d3290a3545dfb4811d945e84e1 commit 1b5e2423164b3670e8bc9174e4762d297990deff upstream. The SSID length as received from firmware should not exceed IEEE80211_MAX_SSID_LEN as that would result in heap overflow. Reviewed-by: Hante Meuleman <hante.meuleman@broadcom.com> Reviewed-by: Pieter-Paul Giesberts <pieter-paul.giesberts@broadcom.com> Reviewed-by: Franky Lin <franky.lin@broadcom.com> Signed-off-by: Arend van Spriel <arend.vanspriel@broadcom.com> Signed-off-by: Kalle Valo <kvalo@codeaurora.org> [bwh: Backported to 3.16: adjust filename, context] Signed-off-by: Ben Hutchings <ben@decadent.org.uk> 
commit 1b5e2423164b3670e8bc9174e4762d297990deff upstream.

The SSID length as received from firmware should not exceed
IEEE80211_MAX_SSID_LEN as that would result in heap overflow.

Reviewed-by: Hante Meuleman <hante.meuleman@broadcom.com>
Reviewed-by: Pieter-Paul Giesberts <pieter-paul.giesberts@broadcom.com>
Reviewed-by: Franky Lin <franky.lin@broadcom.com>
Signed-off-by: Arend van Spriel <arend.vanspriel@broadcom.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
[bwh: Backported to 3.16: adjust filename, context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
vfio/type1: Limit DMA mappings per container 2019-05-02T20:42:03+00:00 Alex Williamson alex.williamson@redhat.com 2019-04-03T18:36:21+00:00 d3334471c34797ab1729cbadddd411118d51c584 commit 492855939bdb59c6f947b0b5b44af9ad82b7e38c upstream. Memory backed DMA mappings are accounted against a user's locked memory limit, including multiple mappings of the same memory. This accounting bounds the number of such mappings that a user can create. However, DMA mappings that are not backed by memory, such as DMA mappings of device MMIO via mmaps, do not make use of page pinning and therefore do not count against the user's locked memory limit. These mappings still consume memory, but the memory is not well associated to the process for the purpose of oom killing a task. To add bounding on this use case, we introduce a limit to the total number of concurrent DMA mappings that a user is allowed to create. This limit is exposed as a tunable module option where the default value of 64K is expected to be well in excess of any reasonable use case (a large virtual machine configuration would typically only make use of tens of concurrent mappings). This fixes CVE-2019-3882. Reviewed-by: Eric Auger <eric.auger@redhat.com> Tested-by: Eric Auger <eric.auger@redhat.com> Reviewed-by: Peter Xu <peterx@redhat.com> Reviewed-by: Cornelia Huck <cohuck@redhat.com> Signed-off-by: Alex Williamson <alex.williamson@redhat.com> [bwh: Backported to 3.16: - Add the out_unlock label in vfio_dma_do_map() - Adjust context] Signed-off-by: Ben Hutchings <ben@decadent.org.uk> 
commit 492855939bdb59c6f947b0b5b44af9ad82b7e38c upstream.

Memory backed DMA mappings are accounted against a user's locked
memory limit, including multiple mappings of the same memory.  This
accounting bounds the number of such mappings that a user can create.
However, DMA mappings that are not backed by memory, such as DMA
mappings of device MMIO via mmaps, do not make use of page pinning
and therefore do not count against the user's locked memory limit.
These mappings still consume memory, but the memory is not well
associated to the process for the purpose of oom killing a task.

To add bounding on this use case, we introduce a limit to the total
number of concurrent DMA mappings that a user is allowed to create.
This limit is exposed as a tunable module option where the default
value of 64K is expected to be well in excess of any reasonable use
case (a large virtual machine configuration would typically only make
use of tens of concurrent mappings).

This fixes CVE-2019-3882.

Reviewed-by: Eric Auger <eric.auger@redhat.com>
Tested-by: Eric Auger <eric.auger@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
[bwh: Backported to 3.16:
 - Add the out_unlock label in vfio_dma_do_map()
 - Adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
media: em28xx: Fix use-after-free when disconnecting 2019-05-02T20:42:02+00:00 Matthias Schwarzott zzam@gentoo.org 2017-10-30T10:07:29+00:00 abbb5cf0c8e9995defed43a6c98296f357098b5b commit 910b0797fa9e8af09c44a3fa36cb310ba7a7218d upstream. Fix bug by moving the i2c_unregister_device calls after deregistration of dvb frontend. The new style i2c drivers already destroys the frontend object at i2c_unregister_device time. When the dvb frontend is unregistered afterwards it leads to this oops: [ 6058.866459] BUG: unable to handle kernel NULL pointer dereference at 00000000000001f8 [ 6058.866578] IP: dvb_frontend_stop+0x30/0xd0 [dvb_core] [ 6058.866644] PGD 0 [ 6058.866646] P4D 0 [ 6058.866726] Oops: 0000 [#1] SMP [ 6058.866768] Modules linked in: rc_pinnacle_pctv_hd(O) em28xx_rc(O) si2157(O) si2168(O) em28xx_dvb(O) em28xx(O) si2165(O) a8293(O) tda10071(O) tea5767(O) tuner(O) cx23885(O) tda18271(O) videobuf2_dvb(O) videobuf2_dma_sg(O) m88ds3103(O) tveeprom(O) cx2341x(O) v4l2_common(O) dvb_core(O) rc_core(O) videobuf2_memops(O) videobuf2_v4l2(O) videobuf2_core(O) videodev(O) media(O) bluetooth ecdh_generic ums_realtek uas rtl8192cu rtl_usb rtl8192c_common rtlwifi usb_storage snd_hda_codec_realtek snd_hda_codec_hdmi snd_hda_codec_generic i2c_mux snd_hda_intel snd_hda_codec snd_hwdep x86_pkg_temp_thermal snd_hda_core kvm_intel kvm irqbypass [last unloaded: videobuf2_memops] [ 6058.867497] CPU: 2 PID: 7349 Comm: kworker/2:0 Tainted: G W O 4.13.9-gentoo #1 [ 6058.867595] Hardware name: MEDION E2050 2391/H81H3-EM2, BIOS H81EM2W08.308 08/25/2014 [ 6058.867692] Workqueue: usb_hub_wq hub_event [ 6058.867746] task: ffff88011a15e040 task.stack: ffffc90003074000 [ 6058.867825] RIP: 0010:dvb_frontend_stop+0x30/0xd0 [dvb_core] [ 6058.867896] RSP: 0018:ffffc90003077b58 EFLAGS: 00010293 [ 6058.867964] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 000000010040001f [ 6058.868056] RDX: ffff88011a15e040 RSI: ffffea000464e400 RDI: ffff88001cbe3028 [ 6058.868150] RBP: ffffc90003077b68 R08: ffff880119390380 R09: 000000010040001f [ 6058.868241] R10: ffffc90003077b18 R11: 000000000001e200 R12: ffff88001cbe3028 [ 6058.868330] R13: ffff88001cbe68d0 R14: ffff8800cf734000 R15: ffff8800cf734098 [ 6058.868419] FS: 0000000000000000(0000) GS:ffff88011fb00000(0000) knlGS:0000000000000000 [ 6058.868511] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 6058.868578] CR2: 00000000000001f8 CR3: 00000001113c5000 CR4: 00000000001406e0 [ 6058.868662] Call Trace: [ 6058.868705] dvb_unregister_frontend+0x2a/0x80 [dvb_core] [ 6058.868774] em28xx_dvb_fini+0x132/0x220 [em28xx_dvb] [ 6058.868840] em28xx_close_extension+0x34/0x90 [em28xx] [ 6058.868902] em28xx_usb_disconnect+0x4e/0x70 [em28xx] [ 6058.868968] usb_unbind_interface+0x6d/0x260 [ 6058.869025] device_release_driver_internal+0x150/0x210 [ 6058.869094] device_release_driver+0xd/0x10 [ 6058.869150] bus_remove_device+0xe4/0x160 [ 6058.869204] device_del+0x1ce/0x2f0 [ 6058.869253] usb_disable_device+0x99/0x270 [ 6058.869306] usb_disconnect+0x8d/0x260 [ 6058.869359] hub_event+0x93d/0x1520 [ 6058.869408] ? dequeue_task_fair+0xae5/0xd20 [ 6058.869467] process_one_work+0x1d9/0x3e0 [ 6058.869522] worker_thread+0x43/0x3e0 [ 6058.869576] kthread+0x104/0x140 [ 6058.869602] ? trace_event_raw_event_workqueue_work+0x80/0x80 [ 6058.869640] ? kthread_create_on_node+0x40/0x40 [ 6058.869673] ret_from_fork+0x22/0x30 [ 6058.869698] Code: 54 49 89 fc 53 48 8b 9f 18 03 00 00 0f 1f 44 00 00 41 83 bc 24 04 05 00 00 02 74 0c 41 c7 84 24 04 05 00 00 01 00 00 00 0f ae f0 <48> 8b bb f8 01 00 00 48 85 ff 74 5c e8 df 40 f0 e0 48 8b 93 f8 [ 6058.869850] RIP: dvb_frontend_stop+0x30/0xd0 [dvb_core] RSP: ffffc90003077b58 [ 6058.869894] CR2: 00000000000001f8 [ 6058.875880] ---[ end trace 717eecf7193b3fc6 ]--- Signed-off-by: Matthias Schwarzott <zzam@gentoo.org> Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com> [bwh: Backported to 3.16: adjust context] Signed-off-by: Ben Hutchings <ben@decadent.org.uk> 
commit 910b0797fa9e8af09c44a3fa36cb310ba7a7218d upstream.

Fix bug by moving the i2c_unregister_device calls after deregistration
of dvb frontend.

The new style i2c drivers already destroys the frontend object at
i2c_unregister_device time.
When the dvb frontend is unregistered afterwards it leads to this oops:

  [ 6058.866459] BUG: unable to handle kernel NULL pointer dereference at 00000000000001f8
  [ 6058.866578] IP: dvb_frontend_stop+0x30/0xd0 [dvb_core]
  [ 6058.866644] PGD 0
  [ 6058.866646] P4D 0

  [ 6058.866726] Oops: 0000 [#1] SMP
  [ 6058.866768] Modules linked in: rc_pinnacle_pctv_hd(O) em28xx_rc(O) si2157(O) si2168(O) em28xx_dvb(O) em28xx(O) si2165(O) a8293(O) tda10071(O) tea5767(O) tuner(O) cx23885(O) tda18271(O) videobuf2_dvb(O) videobuf2_dma_sg(O) m88ds3103(O) tveeprom(O) cx2341x(O) v4l2_common(O) dvb_core(O) rc_core(O) videobuf2_memops(O) videobuf2_v4l2(O) videobuf2_core(O) videodev(O) media(O) bluetooth ecdh_generic ums_realtek uas rtl8192cu rtl_usb rtl8192c_common rtlwifi usb_storage snd_hda_codec_realtek snd_hda_codec_hdmi snd_hda_codec_generic i2c_mux snd_hda_intel snd_hda_codec snd_hwdep x86_pkg_temp_thermal snd_hda_core kvm_intel kvm irqbypass [last unloaded: videobuf2_memops]
  [ 6058.867497] CPU: 2 PID: 7349 Comm: kworker/2:0 Tainted: G        W  O    4.13.9-gentoo #1
  [ 6058.867595] Hardware name: MEDION E2050 2391/H81H3-EM2, BIOS H81EM2W08.308 08/25/2014
  [ 6058.867692] Workqueue: usb_hub_wq hub_event
  [ 6058.867746] task: ffff88011a15e040 task.stack: ffffc90003074000
  [ 6058.867825] RIP: 0010:dvb_frontend_stop+0x30/0xd0 [dvb_core]
  [ 6058.867896] RSP: 0018:ffffc90003077b58 EFLAGS: 00010293
  [ 6058.867964] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 000000010040001f
  [ 6058.868056] RDX: ffff88011a15e040 RSI: ffffea000464e400 RDI: ffff88001cbe3028
  [ 6058.868150] RBP: ffffc90003077b68 R08: ffff880119390380 R09: 000000010040001f
  [ 6058.868241] R10: ffffc90003077b18 R11: 000000000001e200 R12: ffff88001cbe3028
  [ 6058.868330] R13: ffff88001cbe68d0 R14: ffff8800cf734000 R15: ffff8800cf734098
  [ 6058.868419] FS:  0000000000000000(0000) GS:ffff88011fb00000(0000) knlGS:0000000000000000
  [ 6058.868511] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  [ 6058.868578] CR2: 00000000000001f8 CR3: 00000001113c5000 CR4: 00000000001406e0
  [ 6058.868662] Call Trace:
  [ 6058.868705]  dvb_unregister_frontend+0x2a/0x80 [dvb_core]
  [ 6058.868774]  em28xx_dvb_fini+0x132/0x220 [em28xx_dvb]
  [ 6058.868840]  em28xx_close_extension+0x34/0x90 [em28xx]
  [ 6058.868902]  em28xx_usb_disconnect+0x4e/0x70 [em28xx]
  [ 6058.868968]  usb_unbind_interface+0x6d/0x260
  [ 6058.869025]  device_release_driver_internal+0x150/0x210
  [ 6058.869094]  device_release_driver+0xd/0x10
  [ 6058.869150]  bus_remove_device+0xe4/0x160
  [ 6058.869204]  device_del+0x1ce/0x2f0
  [ 6058.869253]  usb_disable_device+0x99/0x270
  [ 6058.869306]  usb_disconnect+0x8d/0x260
  [ 6058.869359]  hub_event+0x93d/0x1520
  [ 6058.869408]  ? dequeue_task_fair+0xae5/0xd20
  [ 6058.869467]  process_one_work+0x1d9/0x3e0
  [ 6058.869522]  worker_thread+0x43/0x3e0
  [ 6058.869576]  kthread+0x104/0x140
  [ 6058.869602]  ? trace_event_raw_event_workqueue_work+0x80/0x80
  [ 6058.869640]  ? kthread_create_on_node+0x40/0x40
  [ 6058.869673]  ret_from_fork+0x22/0x30
  [ 6058.869698] Code: 54 49 89 fc 53 48 8b 9f 18 03 00 00 0f 1f 44 00 00 41 83 bc 24 04 05 00 00 02 74 0c 41 c7 84 24 04 05 00 00 01 00 00 00 0f ae f0 <48> 8b bb f8 01 00 00 48 85 ff 74 5c e8 df 40 f0 e0 48 8b 93 f8
  [ 6058.869850] RIP: dvb_frontend_stop+0x30/0xd0 [dvb_core] RSP: ffffc90003077b58
  [ 6058.869894] CR2: 00000000000001f8
  [ 6058.875880] ---[ end trace 717eecf7193b3fc6 ]---

Signed-off-by: Matthias Schwarzott <zzam@gentoo.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>