[Bionic, Xenial] powerpc/powernv/pci: Work around races in PCI bridge enabling
| Affects | Status | Importance | Assigned to | Milestone | |
|---|---|---|---|---|---|
| The Ubuntu-power-systems project |
New
|
High
|
Canonical Kernel Team | ||
| linux (Ubuntu) |
Triaged
|
High
|
Ubuntu on IBM Power Systems Bug Triage | ||
| Xenial |
Triaged
|
High
|
Unassigned | ||
| Bionic |
Triaged
|
High
|
Unassigned | ||
Bug Description
== Comment: #0 - Breno Leitao <email address hidden> - 2018-08-23 17:52:30 ==
Please apply the following kernel patch into Bionic 4.15 kernel, and Xenial 4.4 kernel.
powerpc/
The generic code is racy when multiple children of a PCI bridge try to
enable it simultaneously.
This leads to drivers trying to access a device through a
not-yet-enabled bridge, and this EEH errors under various
circumstances when using parallel driver probing.
There is work going on to fix that properly in the PCI core but it
will take some time.
x86 gets away with it because (outside of hotplug), the BIOS enables
all the bridges at boot time.
This patch does the same thing on powernv by enabling all bridges that
have child devices at boot time, thus avoiding subsequent races. It's
suitable for backporting to stable and distros, while the proper PCI
fix will probably be significantly more invasive.
Signed-off-by: Benjamin Herrenschmidt <email address hidden>
Cc: <email address hidden>
Signed-off-by: Michael Ellerman <email address hidden>
| tags: | added: architecture-ppc64le bugnameltc-170843 severity-high targetmilestone-inin--- |
| Changed in ubuntu: | |
| assignee: | nobody → Ubuntu on IBM Power Systems Bug Triage (ubuntu-power-triage) |
| affects: | ubuntu → kernel-package (Ubuntu) |
| affects: | kernel-package (Ubuntu) → linux (Ubuntu) |
| Changed in ubuntu-power-systems: | |
| assignee: | nobody → Canonical Kernel Team (canonical-kernel-team) |
| importance: | Undecided → High |
| Changed in linux (Ubuntu): | |
| status: | New → Triaged |
| importance: | Undecided → High |
| Changed in linux (Ubuntu Xenial): | |
| status: | New → Triaged |
| Changed in linux (Ubuntu Bionic): | |
| status: | New → Triaged |
| Changed in linux (Ubuntu Xenial): | |
| importance: | Undecided → High |
| Changed in linux (Ubuntu Bionic): | |
| importance: | Undecided → High |
| bugproxy (bugproxy) wrote Comment bridged from LTC Bugzilla | #1 |
| Andrew Cloke (andrew-cloke) wrote | #2 |
| tags: |
added: targetmilestone-inin1804 removed: targetmilestone-inin--- |
| tags: | added: cscc |
------- Comment From <email address hidden> 2018-09-18 05:30 EDT-------
Any updates on this bug?
FYI, Breno told me that he will take care of verifications from IBM side.