Ubuntu
glibc package

  1. Bug #2011421
  2. Comment #0

Comment 0 for bug 2011421

Revision history for this message
Ioanna Alifieraki (joalif) wrote :

[IMPACT]

Glibc in jammy and kinetic is affected by the following bug :
https://sourceware.org/bugzilla/show_bug.cgi?id=29953

When cpuid reports no information on a shared cache, the
x86_non_temporal_threshold will be set to zero, causing memcpy/memset to
behave wrong for mid-sized operations. sysdeps/x86/dl-cacheinfo.h indicates
that the minimum value must be 0x4040, but this is not enforced for the
default value.

The issue was reported because jammy tdx instances are failing to boot
(crashing) on azure. The bug has been resolved upstream in
https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=48b74865c63840b288bd85b4d8743533b73b339b

[TEST CASE]

Test case requires an azure tdx instance.
Microsoft has tested a test package with the above commit and
confirmed that instances boot successfully.

[REGRESSION POTENTIAL]

The patches have been accepted upstream. They modify code for x86 architecture, so any
potential regression would affect x86.

[OTHER]

In jammy we need 2 commits :
https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=b446822b6ae4e8149902a78cdd4a886634ad6321
https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=48b74865c63840b288bd85b4d8743533b73b339b

In kinetic we just need :
https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=48b74865c63840b288bd85b4d8743533b73b339b