kernel-packages team mailing list archive

[Mathew Hodson <mathew.hodson@xxxxxxxxx>]

** Changed in: linux (Ubuntu)
       Status: In Progress => Fix Released

-- 
You received this bug notification because you are a member of Kernel
Packages, which is subscribed to linux in Ubuntu.
https://bugs.launchpad.net/bugs/901830

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

Status in linux package in Ubuntu:
  Fix Released
Status in linux source package in Oneiric:
  Fix Released

Bug description:
  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

To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/901830/+subscriptions