[Bug 2002429] Re: Patch needs to be removed ("debian/patches/gcc-ibmz-plt-revert.diff: Revert PLT changes from the gcc-11 branch")

[Dimitri John Ledkov]

** Also affects: ubuntu-z-systems
   Importance: Undecided
       Status: New

-- 
You received this bug notification because you are a member of Ubuntu
Foundations Bugs, which is subscribed to gcc-11 in Ubuntu.
https://bugs.launchpad.net/bugs/2002429

Title:
  Patch needs to be removed ("debian/patches/gcc-ibmz-plt-revert.diff:
  Revert PLT changes from the gcc-11 branch")

Status in Ubuntu on IBM z Systems:
  New
Status in gcc-11 package in Ubuntu:
  Fix Released
Status in gcc-11 source package in Jammy:
  New
Status in gcc-11 source package in Kinetic:
  New
Status in gcc-11 source package in Lunar:
  Fix Released
Status in gcc-11 package in Debian:
  New

Bug description:
  [ Impact ]

   * Bug #1954676 (https://bugs.launchpad.net/bugs/1954676) was opened
  because of kernel soft lockup issues with Jammy 5.15. A temporary
  patch to gcc-11 was identified and released under debian/patches/gcc-
  ibmz-plt-revert.diff, which reverted gcc commit 0990d93 ("IBM Z: Use
  @PLT symbols for local functions in 64-bit mode"). An eventual fix to
  the kernel lockup was released under the upstream Linux kernel, commit
  f3b7e73b2c66.

   * To this end, the debian/patches/gcc-ibmz-plt-revert.diff patch
  should be removed from gcc-11 as it presents issues with object file
  symbols. An attempt at this is in my PPA -
  https://launchpad.net/~john-cabaj/+archive/ubuntu/gcc-11). This
  allowed me to get past my issues with the object file symbols.

  [ Test Plan ]

   * use kpatch-build testcases to build and load a livepatch on s390x
  kernel built with gcc-11

   * it should be successful

  [ Where problems could occur ]

   * Whilst the kernel issues was worked-around by reverting compiler
  changes, the actual issue was in the kernel code; which has since been
  fixed. In ubuntu the kernel has been fixed since Ubuntu-5.15.0-20.20

  [ Other Info ]
   
   * A bit sad that this was not detected earlier, and compiler fixed up earlier.

To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu-z-systems/+bug/2002429/+subscriptions