Summary: | Current won't boot on PPC64 Power8 with sparse CPU IDs | ||||||
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Product: | Base System | Reporter: | Luciano Mannucci <luciano> | ||||
Component: | kern | Assignee: | Nathan Whitehorn <nwhitehorn> | ||||
Status: | Closed FIXED | ||||||
Severity: | Affects Some People | CC: | nwhitehorn, swills | ||||
Priority: | Normal | ||||||
Version: | CURRENT | ||||||
Hardware: | Any | ||||||
OS: | Any | ||||||
Attachments: |
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Description
Luciano Mannucci
2016-06-07 16:47:45 UTC
This is a result of disabling threads so that the CPU IDs seen by the system are non-consecutive. As a workaround, you can set threads=8 in your KVM configuration while we fix the underlying problem. Created attachment 171994 [details]
Patch to fix bug
I've just sent the attached patch to freebsd-hackers@ for review. It fixes this particular problem and hopefully will land in the tree before 11.0-BETA1.
Thank you very much for the report.
A commit references this bug: Author: nwhitehorn Date: Wed Jul 6 14:09:51 UTC 2016 New revision: 302372 URL: https://svnweb.freebsd.org/changeset/base/302372 Log: Replace a number of conflations of mp_ncpus and mp_maxid with either mp_maxid or CPU_FOREACH() as appropriate. This fixes a number of places in the kernel that assumed CPU IDs are dense in [0, mp_ncpus) and would try, for example, to run tasks on CPUs that did not exist or to allocate too few buffers on systems with sparse CPU IDs in which there are holes in the range and mp_maxid > mp_ncpus. Such circumstances generally occur on systems with SMT, but on which SMT is disabled. This patch restores system operation at least on POWER8 systems configured in this way. There are a number of other places in the kernel with potential problems in these situations, but where sparse CPU IDs are not currently known to occur, mostly in the ARM machine-dependent code. These will be fixed in a follow-up commit after the stable/11 branch. PR: kern/210106 Reviewed by: jhb Approved by: re (glebius) Changes: head/sys/amd64/include/counter.h head/sys/cddl/compat/opensolaris/sys/proc.h head/sys/dev/cpuctl/cpuctl.c head/sys/i386/include/counter.h head/sys/kern/subr_pcpu.c head/sys/kern/subr_taskqueue.c head/sys/net/flowtable.c head/sys/net/iflib.c head/sys/netinet/ip_id.c head/sys/powerpc/include/counter.h head/sys/powerpc/powerpc/mp_machdep.c head/sys/vm/uma.h head/sys/vm/uma_core.c Fixed for BETA1. Thank you for the report! A commit references this bug: Author: nwhitehorn Date: Wed Aug 31 04:02:53 UTC 2016 New revision: 305108 URL: https://svnweb.freebsd.org/changeset/base/305108 Log: Refix operation on sparse CPU mappings as in r302372, temporarily broken by r304716. PR: kern/210106 MFC after: 2 days Changes: head/sys/kern/imgact_elf.c head/sys/kern/subr_gtaskqueue.c A commit references this bug: Author: nwhitehorn Date: Thu Sep 1 22:27:48 UTC 2016 New revision: 305250 URL: https://svnweb.freebsd.org/changeset/base/305250 Log: MFC r305108,305109: Refix operation on sparse CPU mappings as in r302372, temporarily broken by r304716. PR: kern/210106 Changes: _U stable/11/ stable/11/sys/kern/subr_gtaskqueue.c A commit references this bug: Author: nwhitehorn Date: Fri Sep 2 01:41:57 UTC 2016 New revision: 305267 URL: https://svnweb.freebsd.org/changeset/base/305267 Log: MFS11 r305250: MFC r305108,305109: Refix operation on sparse CPU mappings as in r302372, temporarily broken by r304716. PR: kern/210106 Approved by: re (gjb) Changes: _U releng/11.0/ releng/11.0/sys/kern/subr_gtaskqueue.c |