[ forwarded to the list ] so far, just a brief inspection below...
> > The divide-by-zero is here in kernel/sched.c: > [ ... ] > > fair_delta64 = ls->delta_fair + 1; > ls->delta_fair = 0; > > exec_delta64 = ls->delta_exec + 1; > ls->delta_exec = 0; > > sample_interval64 = this_rq->clock - ls->load_update_last; > ls->load_update_last = this_rq->clock; > > if ((s64)sample_interval64 < (s64)TICK_NSEC) > sample_interval64 = TICK_NSEC; > > if (exec_delta64 > sample_interval64) > exec_delta64 = sample_interval64; > > idle_delta64 = sample_interval64 - exec_delta64; > > ======> tmp64 = div64_64(SCHED_LOAD_SCALE * exec_delta64, fair_delta64); fair_delta64 == 0 and fair_delta64 == ls->delta_fair + 1; so obviously, i.e. ls->delta_fair == -1. delta_fair is of 'insigned long' and calculated in __update_curr_load() by means of calc_delta_mine(). calc_delta_mine() does in the very end: return (unsigned long)min(tmp, (u64)(unsigned long)LONG_MAX); (*) so that means, we likely got 'tmp' > (unsigned long)LONG_MAX in calc_delta_mine()... btw., - fair_delta64 == ls->delta_fair + 1; + fair_delta64 == (u64)ls->delta_fair + 1; in update_cpu_load() would avoid the problem, I guess (and perhaps, can be legitimate, logically-wise). maybe on the system with low HZ value (I can't see the kernel config immediately on the bugzilla page) and a task niced to the lowest priority (is this 'kjournald' mentioned in the report of lower prio? ) running for a full tick, 'tmp' can be such a big value... hmm? -- Best regards, Dmitry Adamushko - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
