Bug 152 - xntpd not compiled to use kernel phase locked loop (pll)
xntpd not compiled to use kernel phase locked loop (pll)
Status: CLOSED WORKSFORME
Product: Red Hat Linux
Classification: Retired
Component: xntp3 (Show other bugs)
5.1
i386 Linux
medium Severity medium
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Assigned To: Jeff Johnson
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Depends On:
Blocks:
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Reported: 1998-11-20 15:44 EST by doug
Modified: 2008-05-01 11:37 EDT (History)
0 users

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Doc Type: Bug Fix
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Last Closed: 1998-11-22 14:39:11 EST
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Description doug 1998-11-20 15:44:27 EST
xntpd support modifying the kernel tick and freq variables
via a call to adjtimex.  xntpd is compiled without the
KERNEL_PLL variable set due to a bug in the configure
script and therefore ends up calling adjtime which is
translated by glibc into a call to adjtimex (0x8001,...)
which tells the kernel to drift the time a certain direction
instead of directly manipulating the kernel time variables
as it does on other platforms.

To verify this do "adjtimex --print" on a machine that has
been running xntpd for several days and notice that the
values for tick and freq are 10000 and 0 as they are at
boot.

Thanks,
Doug
Comment 1 Jeff Johnson 1998-11-22 14:39:59 EST
This bug report has little to do with reality:

1) xntpd *is* compiled with KERNEL_PLL defined in config.h.

2) strace indicates that adjtimex is *not* called with the
the adjtime ADJ_OFFSET_SINGLESHOT (0x8001) through adjtimex
in glibc.

3) Using adjtimex to show the value of tick returns 10000 always
*exactly* as it should since tick is a constant set manually.
The value of frequency is *not* zero.


(All the above observed with xntp3-5.93-5 and adjtimex-1.3-3 on i386)
Comment 2 doug 1998-11-22 22:40:59 EST
Okay, here is what I am seeing...

# uname -a
Linux doug 2.0.35 #1 Thu Jul 23 14:01:04 EDT 1998 i586 unknown
# rpm -q xntp3
xntp3-5.93-4

I could not find the -5 package that you mentioned on any of the
mirror ftp servers and *.redhat.com was too busy.

Here is a line from strace, this is repeated every second:

adjtimex({modes=32769, offset=0, freq=0, maxerror=16384000,
esterror=16384000, status=64, constant=2, precision=1,
tolerance=13107200, time={911806102, 679542}}) = 5

The modes are set to 0x8001 which according to "man 2 adjtimex"
means

#define ADJ_OFFSET_SINGLESHOT 0x8001 /* old-fashioned adjtime */

so unless I have made some error, adjtimex is called with
ADJ_OFFSET_SINGLESHOT.

Also, I went ahead and grabbed the SRPM of the same package
and did rpm -bc specfile and config.h still shows

/* #undef KERNEL_PLL */

If a newer RPM is available, please tell me where I can find it.

Thanks,
Doug

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