Messages in this thread | | | Date | Thu, 15 Mar 2012 15:58:20 +0100 (CET) | From | Thomas Gleixner <> | Subject | Re: ntp: BUG: spinlock lockup on CPU#1 |
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On Thu, 15 Mar 2012, Thomas Gleixner wrote: > CPU 0 CPU 1 > do_adjtimex() > spin_lock_irq(&ntp_lock); > process_adjtimex_modes(); timer_interrupt() > process_adj_status(); do_timer() > ntp_start_leap_timer(); write_lock(&xtime_lock); > hrtimer_start(); update_wall_time(); > hrtimer_reprogram(); ntp_tick_length() > tick_program_event() spin_lock(&ntp_lock); > clockevents_program_event() > ktime_get() > seq = req_seqbegin(xtime_lock); > > So CPU0 waits for xtime seqence to become valid and CPU1 cant make > progress because it's stuck on ntp_lock.
The same problem exists with ntp_clear() being called under the xtime/timekeeper lock write locked. Nasty ...
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