kernel panic after "rmmod cx23885" by upstream commit 2f1ea29f / "[media] si2157: implement signal strength stats"
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
linux (Ubuntu) |
Triaged
|
Medium
|
Unassigned |
Bug Description
[Reported also on <email address hidden>]
* relevance / use-case:
HTPC going into sleep (currently requires rmmod as isolated here)
when not being used.
* base system:
- Ubuntu 15.10 (arch: amd64)
- PCIe DVB-C card DVBSky T982 (2 DVB-C/T tuners)
- starting point: Ubuntu kernel 4.2.x / x86_64
* reliably trigger kernel panic (analyzed with kdb / gdb):
- run tvheadend 4.x using the DVB-C tuners (from git/master in my
case, but actual release should not be that relevant) ... likely
any other DVB-C application would be sufficient.
- stop tvheadend
- rmmod cx23885
Please note: It seems to be relevant that the DVB-C tuners were
in use (and released) before the call to rmmod. During testing,
I had situations where I could successfully do the rmmod if
tvheadend was not yet started after a fresh boot.
The kernel panic happens after the rmmod with a little delay
(less than a second) - in some completely unrelated parts of the
kernel, but reproducible locations, e.g. a stack frame like:
(unable to handle paging request, aka invalid pointer)
or
(null pointer dereference)
The faulting line is a call to NULL or invalid function pointer,
namely line 1178 in media_tree/
1177 trace_timer_
1178 fn(data);
1179 trace_timer_
fn is a null pointer if called within the "if (irqsafe)" block
or an invalid pointer if called from the respective else branch
(ll. 1284 in media_tree/
* Affected:
- v4.2.x
- v4.3.x
- v4.4-rcX
* Not affected: v4.1.x
* Bisect result on git://github.
between v4.1 and v4.2
2f1ea29fca7
commit 2f1ea29fca781b8
Author: Antti Palosaari <crope <at> iki.fi>
Date: Sun Sep 7 11:20:34 2014 -0300
[media] si2157: implement signal strength stats
Implement DVBv5 signal strength stats. Returns dBm.
Tested-by: Adam Baker <linux <at> baker-net.org.uk>
:040000 040000 1fc70a3d18532f9
5130e9b011e9c4b
* Workaround:
Reverting this patch on my tested kernels (incl. 4.4.rc8) prevents
the kernel panic.
BR,
Martin
P.S.: Bisect log:
user <at> host:/a/b/c$ git bisect log
# bad: [64291f7db5bd81
# good: [b953c0d234bc72
git bisect start 'v4.2' 'v4.1'
# bad: [c11d716218910c
git bisect bad c11d716218910c3
# good: [8a8c35fadfaf55
gfp from per_alloc()
git bisect good 8a8c35fadfaf556
# good: [14738e03312ff1
git bisect good 14738e03312ff11
# good: [4570a37169d4b4
git bisect good 4570a37169d4b44
# bad: [78aad7f81aa6df
colorspace/
git bisect bad 78aad7f81aa6dfc
# good: [356484cabe4498
git bisect good 356484cabe44984
# good: [e4aa18d33c3a05
properties API
git bisect good e4aa18d33c3a05f
# good: [e01dfc01914ab9
git bisect good e01dfc01914ab9a
# good: [dc9ef7d11207a0
git bisect good dc9ef7d11207a04
# bad: [5ac417efe66ddd
git bisect bad 5ac417efe66ddd7
# bad: [171fe6d1270d53
required buffers to three
git bisect bad 171fe6d1270d535
# good: [d2b72f6482b9a3
git bisect good d2b72f6482b9a3c
# bad: [694f9963edd831
git bisect bad 694f9963edd831e
# bad: [2f1ea29fca781b
git bisect bad 2f1ea29fca781b8
# first bad commit: [2f1ea29fca781b
strength stats
ProblemType: Bug
DistroRelease: Ubuntu 15.10
Package: linux-image-
ProcVersionSign
Uname: Linux 4.2.0-23-generic x86_64
ApportVersion: 2.19.1-0ubuntu5
Architecture: amd64
AudioDevicesInUse: Error: command ['fuser', '-v', '/dev/snd/by-path', '/dev/snd/hwC1D0', '/dev/snd/
Date: Sat Jan 9 10:53:16 2016
HibernationDevice: RESUME=
InstallationDate: Installed on 2014-07-09 (548 days ago)
InstallationMedia: Ubuntu 14.04 LTS "Trusty Tahr" - Release amd64 (20140417)
IwConfig:
eth0 no wireless extensions.
lo no wireless extensions.
MachineType: ASUS All Series
ProcFB: 0 inteldrmfb
ProcKernelCmdLine: BOOT_IMAGE=
PulseList: Error: command ['pacmd', 'list'] failed with exit code 1: No PulseAudio daemon running, or not running as session daemon.
RelatedPackageV
linux-
linux-
linux-firmware 1.149.3
RfKill:
SourcePackage: linux
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 05/15/2015
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: 2404
dmi.board.
dmi.board.name: H97M-E
dmi.board.vendor: ASUSTeK COMPUTER INC.
dmi.board.version: Rev X.0x
dmi.chassis.
dmi.chassis.type: 3
dmi.chassis.vendor: To Be Filled By O.E.M.
dmi.chassis.
dmi.modalias: dmi:bvnAmerican
dmi.product.name: All Series
dmi.product.
dmi.sys.vendor: ASUS
tags: | added: patch |
tags: | added: bios-outdated-2602 bisect-done |
Changed in linux (Ubuntu): | |
importance: | Undecided → Medium |
status: | Confirmed → Triaged |
This change was made by a bot.