Messages in this thread Patch in this message | | | Date | Fri, 28 Sep 2007 02:49:01 -0700 | From | Paul Jackson <> | Subject | Re: [PATCH 08/10] ia64: Convert cpu_sibling_map to a per_cpu data array (v3) |
| |
Mike,
I think there is a bug either in this ia64 patch, or in the related generic arch patch: Convert cpu_sibling_map to be a per cpu variable (v3).
It dies early in boot on me, on the SGI internal 8 processor IA64 system that you and I know as 'margin'. The death is a hard hang, due to a corrupt stack, due to a bogus cpu index.
I haven't tracked it down all the way, but have gotten this far. If I add the following patch, I get a panic on the BUG_ON if I have these two patches in 2.6.23-rc8-mm1, but it boots just fine if I don't have these two patches.
It seems that the "cpu_sibling_map[cpu]" cpumask_t is empty (all zero bits) with your two patches applied, but has some non-zero bits otherwise, which leads to 'group' being NR_CPUS instead of a useful CPU number. Unfortunately, I have no idea why the "cpu_sibling_map[cpu]" cpumask_t is empty -- good luck on that part.
The patch that catches this bug earlier is this:
--- 2.6.23-rc8-mm1.orig/kernel/sched.c 2007-09-28 01:42:20.144561024 -0700 +++ 2.6.23-rc8-mm1/kernel/sched.c 2007-09-28 02:27:14.239075497 -0700 @@ -5905,6 +5905,7 @@ static int cpu_to_phys_group(int cpu, co #else group = cpu; #endif + BUG_ON(group == NR_CPUS); if (sg) *sg = &per_cpu(sched_group_phys, group); return group;
-- I won't rest till it's the best ... Programmer, Linux Scalability Paul Jackson <pj@sgi.com> 1.925.600.0401 - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |