[SRU][Artful][PATCH 0/3] Fixes for LP:1744988

Joseph Salisbury joseph.salisbury at canonical.com
Thu Feb 1 18:59:26 UTC 2018

BugLink: http://bugs.launchpad.net/bugs/1744988

== SRU Justification ==
The bug reporter observeed NTP time drift on two servers running hwe kernels 
in Xenial. After rebooting the servers to the 4.10 or 4.13 kernels we were 
seeing a big time offset within minutes after booting. Despite running 
ntpd, it would not keep up and the offset stayed and kept growing over time.

This is a regression that did not exist in the 4.4 Xenial kernel.  This regression
is fixed by three mainline commits, da4ae6c4a, b511203093 and 4b5b2127238. All
three commits were added to mainline in v4.15-rc9. 

Bionic already recieved these patches via upstream stable updates.

== Fixes ==
da4ae6c4a0b8 ("x86/tsc: Future-proof native_calibrate_tsc()")
b51120309348 ("x86/tsc: Fix erroneous TSC rate on Skylake Xeon")
4b5b2127238e ("x86/tsc: Print tsc_khz, when it differs from cpu_khz")

== Regression Potential ==
Low.  These three commits fix an existing regression.  They were also cc'd to 
stable so have had addition upstream review.

== Test Case ==
A test kernel was built with these patches and tested by the original bug reporter.
The bug reporter states the test kernel resolved the bug. 

Len Brown (3):
  x86/tsc: Future-proof native_calibrate_tsc()
  x86/tsc: Fix erroneous TSC rate on Skylake Xeon
  x86/tsc: Print tsc_khz, when it differs from cpu_khz

 arch/x86/kernel/tsc.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)


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