On Wed, 2007-07-18 at 09:18 +0200, Ingo Molnar wrote: > * Fernando Lopez-Lezcano <nando@xxxxxxxxxxxxxxxxxx> wrote: > > > > does lockdep pinpoint anything? > > > > Lots of stuff, and at the end the lock report for the problem. > > Hopefully some of this will help... I have attached the whole bootup > > sequence as logged in /var/log/messages. > > yeah, it pinpointed the bug. It seems to be an interaction between > RCU-preempt (Paul Cc:-ed) and sched_mc_power_savings_store(): > detach_destroy_domains() uses synchronize_sched() which uses > getaffinity, which takes sched_hotcpu_mutex, and > arch_reinit_sched_domains does it too - see the lockdep report below. > I've added a quick workaround below as well, which should keep your box > from hanging. I can confirm that flash9 does not hang with the patch. Thanks!!! I presume the same would apply to 2.6.21.x and, say, rt21. I'll test. But (of course, there's always a but somewhere) I just experienced a complete hang - 2.6.22.1-rt4 with the little patch. This time there was something in the logs, maybe it will help? This was when finishing the install of an additional kernel module rpm package (ipw3945 drivers). -- Fernando -------- Jul 18 10:48:15 localhost kernel: BUG: sleeping function called from invalid context modprobe(5001) at kernel/rtmutex.c:636 Jul 18 10:48:15 localhost kernel: in_atomic():1 [00000001], irqs_disabled():0 Jul 18 10:48:15 localhost kernel: [<c0405f34>] show_trace_log_lvl +0x1a/0x2f Jul 18 10:48:15 localhost kernel: [<c0406a09>] show_trace+0x12/0x14 Jul 18 10:48:15 localhost kernel: [<c0406a71>] dump_stack+0x16/0x18 Jul 18 10:48:15 localhost kernel: [<c0423bfc>] __might_sleep+0xeb/0xf2 Jul 18 10:48:15 localhost kernel: [<c0617242>] __rt_spin_lock+0x24/0x40 Jul 18 10:48:15 localhost kernel: [<c0617266>] rt_spin_lock+0x8/0xa Jul 18 10:48:15 localhost kernel: [<c04621c9>] get_zone_pcp+0x23/0x33 Jul 18 10:48:15 localhost kernel: [<c0462702>] free_hot_cold_page +0xcf/0x148 Jul 18 10:48:15 localhost kernel: [<c04627b2>] free_hot_page+0xa/0xc Jul 18 10:48:15 localhost kernel: [<c0462a82>] __free_pages+0x25/0x30 Jul 18 10:48:15 localhost kernel: [<c0462ab6>] free_pages+0x29/0x2b Jul 18 10:48:15 localhost kernel: [<c047abf3>] quicklist_trim+0xd0/0xf5 Jul 18 10:48:15 localhost kernel: [<c041f5d9>] check_pgt_cache +0x1e/0x20 Jul 18 10:48:15 localhost kernel: [<c046aedf>] free_pgtables+0x52/0x147 Jul 18 10:48:15 localhost kernel: [<c046cdf7>] unmap_region+0xe6/0x135 Jul 18 10:48:15 localhost kernel: [<c046d764>] do_munmap+0x153/0x1b4 Jul 18 10:48:15 localhost kernel: [<c046f3de>] do_mremap+0x413/0x4c3 Jul 18 10:48:15 localhost kernel: [<c046f4c4>] sys_mremap+0x36/0x56 Jul 18 10:48:15 localhost kernel: [<c0404fca>] syscall_call+0x7/0xb Jul 18 10:48:15 localhost kernel: ======================= Jul 18 10:48:16 localhost kernel: BUG: sleeping function called from invalid context head(5652) at kernel/rtmutex.c:636 Jul 18 10:48:16 localhost kernel: in_atomic():1 [00000001], irqs_disabled():0 Jul 18 10:48:16 localhost kernel: [<c0405f34>] show_trace_log_lvl +0x1a/0x2f Jul 18 10:48:16 localhost kernel: [<c0406a09>] show_trace+0x12/0x14 Jul 18 10:48:16 localhost kernel: [<c0406a71>] dump_stack+0x16/0x18 Jul 18 10:48:16 localhost kernel: [<c0423bfc>] __might_sleep+0xeb/0xf2 Jul 18 10:48:16 localhost kernel: [<c0617242>] __rt_spin_lock+0x24/0x40 Jul 18 10:48:16 localhost kernel: [<c0617266>] rt_spin_lock+0x8/0xa Jul 18 10:48:16 localhost kernel: [<c04621c9>] get_zone_pcp+0x23/0x33 Jul 18 10:48:16 localhost kernel: [<c0462702>] free_hot_cold_page +0xcf/0x148 Jul 18 10:48:16 localhost kernel: [<c04627b2>] free_hot_page+0xa/0xc Jul 18 10:48:16 localhost kernel: [<c0462a82>] __free_pages+0x25/0x30 Jul 18 10:48:16 localhost kernel: [<c0462ab6>] free_pages+0x29/0x2b Jul 18 10:48:16 localhost kernel: [<c047abf3>] quicklist_trim+0xd0/0xf5 Jul 18 10:48:16 localhost kernel: [<c041f5d9>] check_pgt_cache +0x1e/0x20 Jul 18 10:48:16 localhost kernel: [<c046aedf>] free_pgtables+0x52/0x147 Jul 18 10:48:16 localhost kernel: [<c046cdf7>] unmap_region+0xe6/0x135 Jul 18 10:48:16 localhost kernel: [<c046d764>] do_munmap+0x153/0x1b4 Jul 18 10:48:16 localhost kernel: [<c046d7f5>] sys_munmap+0x30/0x3f Jul 18 10:48:16 localhost kernel: [<c0404fca>] syscall_call+0x7/0xb Jul 18 10:48:16 localhost kernel: ======================= Jul 18 10:50:22 localhost syslogd 1.4.2: restart. - 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
