kernel-packages team mailing list archive

[Vincent Bernat <bernat@xxxxxxxxxx>]

Public bug reported:

Hi!

Tools, like systemtap, need to circumvent some bugs in GCC, notably in
the way it reports debugging data for highly-optimized programs.
Systemtap includes workarounds but they are only reliable when the
kernel is using some options. Therefore, systemtap needs to know with
which option GCC was invoked.

For example, LTS kernels for Precise are using GCC 4.6.3 Precise which
has a bug related to -mfentry and produce incorrect offsets for
debugging symbols (off by 5). Systemtap includes a workaround for this
but it can only be reliably detected if it knows that -mfentry flag was
requested.

This can be done by using CFLAGS=-grecord-gcc-switches. Please, use it
for all future release, even when the version of GCC used has no known
bug.

Thanks.

** Affects: linux (Ubuntu)
     Importance: Undecided
         Status: New

-- 
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/1233014

Title:
  Use CFLAGS=-grecord-gcc-switches

Status in “linux” package in Ubuntu:
  New

Bug description:
  Hi!

  Tools, like systemtap, need to circumvent some bugs in GCC, notably in
  the way it reports debugging data for highly-optimized programs.
  Systemtap includes workarounds but they are only reliable when the
  kernel is using some options. Therefore, systemtap needs to know with
  which option GCC was invoked.

  For example, LTS kernels for Precise are using GCC 4.6.3 Precise which
  has a bug related to -mfentry and produce incorrect offsets for
  debugging symbols (off by 5). Systemtap includes a workaround for this
  but it can only be reliably detected if it knows that -mfentry flag
  was requested.

  This can be done by using CFLAGS=-grecord-gcc-switches. Please, use it
  for all future release, even when the version of GCC used has no known
  bug.

  Thanks.

To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1233014/+subscriptions