[Bug libc/9690] glibc time functionality broken with kernel 2.6.26 and later

["johnstul at us dot ibm dot com" <sourceware-bugzilla at sourceware dot org>]

------- Additional Comments From johnstul at us dot ibm dot com  2009-05-07 21:28 -------
(In reply to comment #4)
> Please do not mix two things:
> 
> - the kernel now exposes nanoseconds instead of microseconds.  That's a
> kernel ABI break.  It is announced via a STA_NANO flag in timex.status,
> but still, old applications are broken when started under kernels >=
> 2.6.26.  That's really a concern as it's not even easy to notice while
> it can irritate users (unstable ntp time).

I'm not sure this is true. The kernel internally multiplies microseconds up to
nanoseconds if the STA_NANO bit is not set. So old applications should behave
properly.

> - the kernel now exposes a new tai field.  That's not a kernel ABI break
> as it just takes a reserved room.  To expose it to applications we
> however need to change the userland ABI.

This is my understanding as well.

> I'd really much rather see a kernel fix for the first issue: the kernel
> should report nanoseconds _only_ if userland requests it.  And the case
> of a new application running with an old kernel _has_ to be taken care
> of as well.

Please bring this up on lkml and CC me if you have evidence of problems here.
I'll be happy to look at it.

> As for the second issue, see Ulrich's comment: just define a new
> version. See for instance the sched_setaffinity() function that has
> changed its ABI (and API too actually).

Do we know if anyone is still working this? Roman's patch was seemingly ignored
with no feedback. Additionally he's not been around much recently, so I'm not
sure if he will be following up with fixes.


-- 
           What    |Removed                     |Added
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                 CC|                            |johnstul at us dot ibm dot
                   |                            |com, mlichvar at redhat dot
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http://sourceware.org/bugzilla/show_bug.cgi?id=9690

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