Hi Sebastian, We finally traced the boot-up crash to the following patch in kernel/sched/core.c: https://git.kernel.org/cgit/linux/kernel/git/rt/linux-stable-rt.git/commit/?h=v3.18-rt&id=62044e554f14547061afcfef7f0aceda43e28982 After reverting the two-line patch in 3.18.29-rt30, the crash no longer occurs on our dual Xeon (2x12 core) system. Other observations: - Does not reproduce on single processor (2 and 4 core) systems - Reproduces under 3.18.27-rt27 and 3.18.36-rt38 on the dual Xeon - Does not reproduce on 3.18.27-rt26 and earlier on the dual Xeon - Reproduces more frequently on .29-rt30 (1 in 20 reboots) compared to .27-rt27 (1 in 100 reboots) So far we've not observed any side effects after reverting this patch. I understand that a high core count system may not be easy to come by, so if there are diagnostics or patches you would like to try on the dual Xeon system, we can assist with that. Cheers, Carol Wong NetAcquire Corporation > -----Original Message----- > From: linux-rt-users-owner@xxxxxxxxxxxxxxx [mailto:linux-rt-users- > owner@xxxxxxxxxxxxxxx] On Behalf Of Sebastian Andrzej Siewior > Sent: Tuesday, June 07, 2016 1:37 AM > To: David Hauck > Cc: linux-rt-users@xxxxxxxxxxxxxxx > Subject: Re: v3.18-RT > > On 06/06/2016 07:45 PM, David Hauck wrote: > > Hi Sebastian, > > Hi, > > > Thx, here's one - hope this might be helpful: > > > > [ 1.352165] BUG: unable to handle kernel > > [ 1.352167] paging request > > [ 1.352169] at a93c2560 > > [ 1.352172] IP: > > [ 1.352178] [<c107c248>] can_migrate_task+0x58/0x220 > > [ 1.352182] *pde = 00000000 > > most of it should be one line. > > this comes down to > if (!cpumask_test_cpu(env->dst_cpu, tsk_cpus_allowed(p))) { > > in can_migrate_task() and the crash happens because the pointer > returned in tsk_cpus_allowed() is invalid. Currently nothing rings a > bell. > > > Great, thx, we'll get started on this this week. > > okay. > > > > > Thanks again, > > -David > > Sebastian > -- > To unsubscribe from this list: send the line "unsubscribe linux-rt- > users" in the body of a message to majordomo@xxxxxxxxxxxxxxx More > majordomo info at http://vger.kernel.org/majordomo-info.html ��.n��������+%������w��{.n�����{�����ǫ���ܨ}���Ơz�j:+v�����w����ޙ��&�)ߡ�a����z�ޗ���ݢj��w�f
