Public bug reported:
[Impact]
Causes fault which can lead to a hang or crash on ARM systems when loading the
ipmi_si module.
The ipmi_si driver includes code that probes into iospace for a KCS
interface. This is to support platforms that don't expose this interface
in SMBIOS/ACPI tables, and this is a defined discovery mechanism as per
the IPMI Spec (v2.0r1, section 9.5). However, this assumption is
x86-centric. It is not safe to blindly probe I/O space on ARM platforms.
[Test Case]
sudo modprobe ipmi_si
This should discover an IPMI system interface if present, or fail to
load otherwise. But it should not cause a hang, a synchronous external
abort, or other kernel failure.
[Regression Risk]
The proposed fix is only to the ARM config, so the risk to other architectures
is negligible. There is a risk that there exists some system out there where
this probing works - but I'm highly confident no such system exists. Existing
ARM systems supported by Ubuntu either describe their IPMI/KCS interface using
device-tree or do not provide one.
** Affects: linux (Ubuntu)
Importance: High
Assignee: dann frazier (dannf)
Status: In Progress
** Affects: linux (Ubuntu Trusty)
Importance: High
Assignee: dann frazier (dannf)
Status: In Progress
** Affects: linux (Ubuntu Utopic)
Importance: High
Assignee: dann frazier (dannf)
Status: In Progress
** Affects: linux (Ubuntu Vivid)
Importance: High
Assignee: dann frazier (dannf)
Status: In Progress
** Tags: hs-arm64
** Also affects: linux (Ubuntu Trusty)
Importance: Undecided
Status: New
** Also affects: linux (Ubuntu Vivid)
Importance: High
Assignee: dann frazier (dannf)
Status: In Progress
** Also affects: linux (Ubuntu Utopic)
Importance: Undecided
Status: New
** Changed in: linux (Ubuntu Utopic)
Status: New => In Progress
** Changed in: linux (Ubuntu Trusty)
Status: New => In Progress
** Changed in: linux (Ubuntu Utopic)
Importance: Undecided => High
** Changed in: linux (Ubuntu Trusty)
Importance: Undecided => High
** Changed in: linux (Ubuntu Utopic)
Assignee: (unassigned) => dann frazier (dannf)
** Changed in: linux (Ubuntu Trusty)
Assignee: (unassigned) => dann frazier (dannf)
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https://bugs.launchpad.net/bugs/1388952
Title:
CONFIG_IPMI_SI_PROBE_DEFAULTS should be disabled on ARM
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