11 minute NTP hw clock update racy?

Joakim Tjernlund Joakim.Tjernlund at infinera.com
Mon Aug 27 18:01:15 AEST 2018


We see corrupt HW clock time every now and then(really hard to reproduce)
Our RTC is a DS1388 on an I2C bus.

Looking at ntp_notify_cmos_timer() and it's delayed work queue impl. I wonder
if there could be a race here w.r.t reboot ?

Could the 11 minute update kick in just as the system is about to reset
the CPU?

I am on 4.14.51, ppc32 and using the ppc_md.restart() hook which will
reset the CPU immediately.

Question, is safe to call ntp_notify_cmos_timer() when the work queue is already
armed(like do_adjtimex() does) ? 

 Jocke


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