From Bugzilla Helper: User-Agent: Mozilla/5.0 (X11; U; Linux i586; en-US; rv:1.7.3) Gecko/20041020 Description of problem: The kernel code, when setting the BIOS clock notes that the clock time ticks to the next second 0.5 seconds after adjusting it (see linux/arch/i386/kernel/time.c) It looks like this was a bug fixed in 1995, but I've not checked. This is probably only actually used for when the system time is externally synced, but I havn't checked. hwclock --systohc sets the CMOS clock at the 1 second boundry and thus causes the clock to be wrong by 500ms each time it is reset. If (as is normal on FC3 at least) the clock is set every shutdown then the clock will have a reboot-count related drift as well as the natural drift problems of the clock. Note that this also mucks up the drift calculations, of course. Version-Release number of selected component (if applicable): util-linux-2.12a-16 and earlier How reproducible: Always Steps to Reproduce: 1.sync system clock to external timeserver 2.hwclock --systohc ; hwclock --hctosys 3.Repeat (2) another 9 times for greater visibility. 4.set system clock to external timeserver. 5.hwclock ; time +%c%N Note the 0.5 second offset for each time (2) was done - total of about 5 seconds. Additional info:
Created attachment 111752 [details] Change timing delay to wait for half-second rather than full second before writing to CMOS I've hacked together this patch and it seems to work - hwclock --systohc now sets the cmos clock to the same value the kernel does when in "11 minute mode", as opposed to 0.5 seconds out. Obviously another set of eyes should check it!
Fedora Core 3 is now maintained by the Fedora Legacy project for security updates only. If this problem is a security issue, please reopen and reassign to the Fedora Legacy product. If it is not a security issue and hasn't been resolved in the current FC5 updates or in the FC6 test release, reopen and change the version to match. Thank you!
Still happens.
The bug has been fixed in the util-linux-ng upstream code and will be also fixed in FC ASAP.