** Description changed:
[Impact]
Disconnecting a thunderbolt docking station on a Dell Inc. XPS 13
9360/0D4J15 can cause a general protection fault (with kernel 5.3.0-40
and above).
The bug has been introduced by this upstream commit:
- ffe3bcaf02c4 ptp: fix the race between the release of ptp_clock and
+ ffe3bcaf02c4 ptp: fix the race between the release of ptp_clock and
cdev
Reverting the commit is not a viable option, because we would re-
introduce another bug.
- The fix is to do something similar to this:
+ The proper fix is to do something similar to this:
- 75718584cb3c64e6269109d4d54f888ac5a5fd15 "ptp: free ptp device pin
+ 75718584cb3c64e6269109d4d54f888ac5a5fd15 "ptp: free ptp device pin
descriptors properly"
- and call posix_clock_unregister() in ptp_clock_release(). NOTE: this bug
- is also present upstream!
-
- In addition to that it seems that we can also trigger a kernel oops with
- the igb driver if this additional upstream fix is not applied:
-
- 94bc1e522b32c866d85b5af0ede55026b585ae73 ("igb/igc: Don't warn on
- fatal read failures when the device is removed")
+ and call pps_unregister_source() in ptp_clock_release(). NOTE: this bug
+ is also present upstream.
[Test case]
Bug reported provided the test case by physically disconnecting the
- docking station. The problems can be easily reproduced.
+ docking station. The problems can be easily reproduced and it doesn't
+ seem to happen anymore with the fix applied.
[Fix]
- Apply upstream commit:
-
- 94bc1e522b32c866d85b5af0ede55026b585ae73 ("igb/igc: Don't warn on
- fatal read failures when the device is removed")
-
- And a custom patch to call call posix_clock_unregister() from
- ptp_clock_release().
+ Call call pps_unregister_source() from ptp_clock_release() instead of
+ ptp_clock_unregister().
[Regression potential]
- About the upstream commit the regression potential is minimal. The other
- custom fix seems to be pretty straightforward. We may consider to post
- this upstream and wait for a better feedback from the community.
+ Minimal regression potential, the change is limited to the ptp clock
+ unregistering code path.
[Original report]
happens each time on kernel 5.3.0-40 when I disconnect thunderbolt docking
station.
Does *not* happen on 5.3.0-28.
After it happens almost everything still works ok: the only malfunction I've
noticed is that after reconnecting the dock, USB devices (mouse, keyboard)
connected via the dock don't work at all. However monitor connected via the
dock still works fine.
Hardware essentials:
Dell Inc. XPS 13 9360/0D4J15, BIOS 2.13.0
Plugable TBT3-UDV Docking Station
Does not happen when disconnecting "simpler" devices like apple's usb-c
to hdmi/usb/usb-c adapter.
ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: linux-image-5.3.0-40-generic 5.3.0-40.32~18.04.1
ProcVersionSignature: Ubuntu 5.3.0-40.32~18.04.1-generic 5.3.18
Uname: Linux 5.3.0-40-generic x86_64
ApportVersion: 2.20.9-0ubuntu7.11
Architecture: amd64
Date: Wed Feb 26 05:23:00 2020
InstallationDate: Installed on 2020-01-01 (55 days ago)
InstallationMedia: Ubuntu-MATE 18.04.3 LTS "Bionic Beaver" - Release amd64
(20190805)
ProcEnviron:
LANGUAGE=en_IE:en
TERM=xterm
PATH=(custom, no user)
LANG=en_IE.UTF-8
SHELL=/bin/bash
SourcePackage: linux-signed-hwe
UpgradeStatus: No upgrade log present (probably fresh install)
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https://bugs.launchpad.net/bugs/1864754
Title:
Kernel Oops - general protection fault: 0000 [#1] SMP PTI after
disconnecting thunderbolt docking station
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