A device using level triggered interrupt will not generate any interrupts in the kdump kernel

[Brad Figg]

SRU Justification

Impact
---------
In the kdump scenario mentioned below, we can have a case where the device
using level triggered interrupt will not generate any interrupts in the
kdump kernel.

1. IO-APIC sends a level triggered interrupt to the CPU's local APIC
2. Kernel crashed before the CPU services this interrupt, leaving the remoteIRR
   in the IO-APIC set
3. kdump kernel boot sequence does clear_IO_APIC() as part of IO-APIC
   initialization. But this fails to reset remoteIRR bit of the IO-APIC RTE
   as the remoteIRR bit is read-only.
4. Device using that level triggered entry can't generate any more interrupts
   because of the remoteIRR bit.

In clear_IO_APIC_pin(), check if the remoteIRR bit is set and if so
do an explicit attempt to clear it (by doing EOI write on modern io-apic's
and changing trigger mode to edge/level on older io-apic's).

Fix
----
upstream commit 1e75b31d638d5242ca8e9771dfdcbd28a5f041df

Testcase
------------
TBD

[Herton R. Krzesinski (herton)]

This bug is awaiting verification that the kernel in -proposed solves the problem. Please test the kernel and update this bug with the results. If the problem is solved, change the tag 'verification-needed-oneiric' to 'verification-done-oneiric'.

If verification is not done by one week from today, this fix will be dropped from the source code, and this bug will be closed.

See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Thank you!

[Brad Figg (brad-figg)]

I do not have a specific test case where I can verify this commit. However, this is a clean cherry-pick of an upstream commit. This is a debugging aid used by various support folks when diagnosing problems on customers systems. This commit was specifically asked for inclusion by Intel.

[Launchpad Janitor (janitor)]

This bug was fixed in the package linux - 3.0.0-15.25

---------------
linux (3.0.0-15.25) oneiric-proposed; urgency=low

  [Brad Figg]

  * Release Tracking Bug
    - LP: #910894

  [ Upstream Kernel Changes ]

  * Revert "clockevents: Set noop handler in clockevents_exchange_device()"
    - LP: #904569

linux (3.0.0-15.24) oneiric-proposed; urgency=low

  [Herton R. Krzesinski]

  * Release Tracking Bug
    - LP: #903188

  [ Alex Bligh ]

  * (config) Change Xen paravirt drivers to be built-in
    - LP: #886521

  [ Chase Douglas ]

  * Revert "SAUCE: HID: hid-ntrig: add support for 1b96:0006 model"
    - LP: #724831
  * Revert "SAUCE: hid: ntrig: Remove unused device ids"
    - LP: #724831

  [ Seth Forshee ]

  * SAUCE: dell-wmi: Demote unknown WMI event message to pr_debug
    - LP: #581312

  [ Upstream Kernel Changes ]

  * Revert "leds: save the delay values after a successful call to
    blink_set()"
    - LP: #893741
  * xfs: Fix possible memory corruption in xfs_readlink, CVE-2011-4077
    - LP: #887298
    - CVE-2011-4077
  * drm/i915: fix IVB cursor support
    - LP: #893222
  * drm/i915: always set FDI composite sync bit
    - LP: #893222
  * jbd/jbd2: validate sb->s_first in journal_get_superblock()
    - LP: #893148
    - CVE-2011-4132
  * ALSA: hda - Don't add elements of other codecs to vmaster slave
    - LP: #893741
  * virtio-pci: fix use after free
    - LP: #893741
  * ASoC: Don't use wm8994->control_data in wm8994_readable_register()
    - LP: #893741
  * sh: Fix cached/uncaced address calculation in 29bit mode
    - LP: #893741
  * drm/i915: Fix object refcount leak on mmappable size limit error path.
    - LP: #893741
  * drm/nouveau: initialize chan->fence.lock before use
    - LP: #893741
  * drm/radeon/kms: make an aux failure debug only
    - LP: #893741
  * ALSA: usb-audio - Check the dB-range validity in the later read, too
    - LP: #893741
  * ALSA: usb-audio - Fix the missing volume quirks at delayed init
    - LP: #893741
  * KEYS: Fix a NULL pointer deref in the user-defined key type
    - LP: #893741
  * hfs: add sanity check for file name length
    - LP: #893741
  * drm/radeon: add some missing FireMV pci ids
    - LP: #893741
  * sfi: table irq 0xFF means 'no interrupt'
    - LP: #893741
  * x86, mrst: use a temporary variable for SFI irq
    - LP: #893741
  * b43: refuse to load unsupported firmware
    - LP: #893741
  * md/raid5: abort any pending parity operations when array fails.
    - LP: #893741
  * mfd: Fix twl4030 dependencies for audio codec
    - LP: #893741
  * xen:pvhvm: enable PVHVM VCPU placement when using more than 32 CPUs.
    - LP: #893741
  * xen-gntalloc: integer overflow in gntalloc_ioctl_alloc()
    - LP: #893741
  * xen-gntalloc: signedness bug in add_grefs()
    - LP: #893741
  * powerpc/ps3: Fix lost SMP IPIs
    - LP: #893741
  * powerpc: Copy down exception vectors after feature fixups
    - LP: #893741
  * backing-dev: ensure wakeup_timer is deleted
    - LP: #893741
  * block: Always check length of all iov entries in blk_rq_map_user_iov()
    - LP: #893741
  * Linux 3.0.10
    - LP: #893741
  * drm/i915: add multi-threaded forcewake support
    - LP: #891270
  * (pre-sta...