Date:	Wed, 30 Jul 2008 12:35:54 +0200
From:	"Dmitry Adamushko" <dmitry.adamushko@...il.com>
To:	"Alistair John Strachan" <alistair@...zero.co.uk>
Cc:	"Pekka Paalanen" <pq@....fi>,
	"Linus Torvalds" <torvalds@...ux-foundation.org>,
	"Linux Kernel Mailing List" <linux-kernel@...r.kernel.org>,
	shaohua.li@...el.com, tigran@...azian.fsnet.co.uk,
	"Ingo Molnar" <mingo@...e.hu>,
	"Thomas Gleixner" <tglx@...utronix.de>,
	"Steven Rostedt" <rostedt@...dmis.org>,
	"Max Krasnyansky" <maxk@...lcomm.com>
Subject: Re: Oops in microcode sysfs registration,

2008/7/30 Dmitry Adamushko <dmitry.adamushko@...il.com>:
> 2008/7/29 Alistair John Strachan <alistair@...zero.co.uk>:
>> On Tuesday 29 July 2008 17:22:14 Pekka Paalanen wrote:
>>> > Also, I'm sure this is reproducible without the NVIDIA garbage, but I was
>>> > too lazy to test it. If you want me to repeat the experiment without the
>>> > driver I would be more than happy to do so.
>>>
>>> I'm not sure people are willing to look into this without a clean report,
>>> so this would be cool. There's even a test module for mmiotrace in the
>>> kernel, but I doubt it would make difference to use it or not, when trying
>>> to reproduce the crash without the blob.
>>
>> Of course, and I should have attempted to reproduce without the driver.
>> Fortunately that was easy: it is not an NVIDIA driver bug.
>>
>> Steps to reproduce: have CONFIG_MICROCODE=y and a suitable Intel
>> processor, then do:
>>
>> echo mmiotrace >/debug/tracing/current_tracer
>> echo none >/debug/tracing/current_tracer
>>
>> And you get this (snipped) oops:
>>
>> in mmio_trace_init
>> mmiotrace: Disabling non-boot CPUs...
>> kvm: disabling virtualization on CPU1
>> CPU 1 is now offline
>> SMP alternatives: switching to UP code
>> CPU0 attaching NULL sched-domain.
>> CPU1 attaching NULL sched-domain.
>> CPU0 attaching NULL sched-domain.
>> mmiotrace: CPU1 is down.
>> mmiotrace: enabled.
>> in mmio_trace_reset
>> mmiotrace: Re-enabling CPUs...
>> SMP alternatives: switching to SMP code
>> Booting processor 1/1 ip 6000
>> Initializing CPU#1
>> Calibrating delay using timer specific routine.. <6>7204.76 BogoMIPS (lpj=3602381)
>> CPU: L1 I cache: 32K, L1 D cache: 32K
>> CPU: L2 cache: 4096K
>> CPU: Physical Processor ID: 0
>> CPU: Processor Core ID: 1
>> x86 PAT enabled: cpu 1, old 0x7040600070406, new 0x7010600070106
>> CPU1: Intel(R) Core(TM)2 CPU          6600  @ 2.40GHz stepping 06
>> checking TSC synchronization [CPU#0 -> CPU#1]: passed.
>> kvm: enabling virtualization on CPU1
>> CPU0 attaching NULL sched-domain.
>> Switched to high resolution mode on CPU 1
>> CPU0 attaching sched-domain:
>>  domain 0: span 0-1 level MC
>>  groups: 0 1
>> CPU1 attaching sched-domain:
>>  domain 0: span 0-1 level MC
>>  groups: 1 0
>> ------------[ cut here ]------------
>> Kernel BUG at ffffffff8021a31d [verbose debug info unavailable]
>> invalid opcode: 0000 [1] PREEMPT SMP
>> CPU 0
>> Modules linked in: rfcomm l2cap kvm_intel kvm ipt_MASQUERADE iptable_nat nf_nat nf_conntrack_ipv4 nf_conntrack ip_tables x_tables bridge stp llc acpi_cpufreq freq_table coretemp hwmon
>> snd_pcm_oss snd_mixer_oss firewire_sbp2 hci_usb bluetooth arc4 ecb crypto_blkcipher cryptomgr crypto_algapi usbhid zd1211rw mac80211 crypto cfg80211 snd_emu10k1 snd_rawmidi
>> snd_ac97_codec ac97_bus sg snd_seq_device snd_hda_intel snd_pcm snd_util_mem snd_timer sr_mod snd_hwdep i2c_i801 ehci_hcd firewire_ohci uhci_hcd snd snd_page_alloc firewire_core
>> soundcore r8169 cdrom usbcore i2c_core crc_itu_t
>> Pid: 2757, comm: bash Tainted: G       A  2.6.27-rc1-damocles #3
>> RIP: 0010:[<ffffffff8021a31d>]  [<ffffffff8021a31d>] __mc_sysdev_add+0xc3/0x1f1
>> RSP: 0018:ffff8800b8905ce8  EFLAGS: 00010297
>> RAX: 0000000000000000 RBX: 0000000000000001 RCX: ffff880080a04000
>> RDX: ffffffff8062c680 RSI: 0000000000000003 RDI: ffffffff8059e830
>> RBP: ffff8800b8905d48 R08: ffff8800b8904000 R09: ffffffff80229ca4
>> R10: ffff8800010247b0 R11: ffff8800bf879de0 R12: 0000000000000018
>> R13: 0000000000000001 R14: 0000000000000000 R15: 0000000000000000
>> FS:  00007f8ddc78f6e0(0000) GS:ffffffff805da200(0000) knlGS:0000000000000000
>> CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
>> CR2: 00007f57cb9b2098 CR3: 00000000b8985000 CR4: 00000000000026e0
>> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
>> DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
>> Process bash (pid: 2757, threadinfo ffff8800b8904000, task ffff8800bd125640)
>> Stack:  ffffffff80627040 0000000000000000 0000000000000008 ffffffff8048bb28
>>  0000000000000003 ffffffff802ce910 ffff8800b8905d28 0000000000000002
>>  00000000ffffffe8 0000000000000001 0000000000000001 ffff880001028418
>> Call Trace:
>>  [<ffffffff802ce910>] ? sysfs_add_file+0xc/0xe
>>  [<ffffffff8021a456>] mc_sysdev_add+0xb/0xd
>>  [<ffffffff8047baaf>] mc_cpu_callback+0x4b/0x208
>>  [<ffffffff8047b772>] ? mce_cpu_callback+0x3e/0xbc
>>  [<ffffffff8024b787>] notifier_call_chain+0x33/0x5b
>>  [<ffffffff8024b81f>] raw_notifier_call_chain+0xf/0x11
>>  [<ffffffff8047e1dc>] _cpu_up+0xce/0x119
>>  [<ffffffff8047e285>] cpu_up+0x5e/0x8a
>>  [<ffffffff80224967>] disable_mmiotrace+0xfe/0x173
>>  [<ffffffff80265279>] mmio_trace_reset+0x2d/0x44
>>  [<ffffffff80262c4d>] tracing_set_trace_write+0xd3/0x10f
>>  [<ffffffff80289cab>] ? filp_close+0x67/0x72
>>  [<ffffffff8028bee3>] vfs_write+0xa7/0xe1
>>  [<ffffffff8028bfe1>] sys_write+0x47/0x6f
>>  [<ffffffff8020b6db>] system_call_fastpath+0x16/0x1b
>> [   68.405002]
>> [   68.405002]
>> Code: e8 59 80 e8 fd 69 26 00 48 c7 c2 80 c6 62 80 48 8b 05 c0 00 3c 00 48 8b 04 d8 48 8b 48 08 65 8b 04 25 24 00 00 00 44 39 e8 74 04 <0f> 0b eb fe 4c 8d 04 0a 41 c7 84 24 7c 36 64 80 00
>> 00 00 00 41
>> RIP  [<ffffffff8021a31d>] __mc_sysdev_add+0xc3/0x1f1
>>  RSP <ffff8800b8905ce8>
>> ---[ end trace ee9c9240024cb48c ]---
>>
>> I've replaced the originally tainted dmesg with this new clean one, so
>> there's no proprietary smell about it :-)
>
> Yes, it's kind of a known issue. Take a look at this explanation:
> http://lkml.org/lkml/2008/7/24/260
>
> There were a few related discussions in other threads (mainly, Max
> Krasnyansky and I were asking for additional info on possible
> requirements from the 'microcode' driver...) heh, I think, we'd be
> better off just fixing it one way or another.

does a patch below fix it for you?
[ not really what we wanted ]

(non-white-space-damaged version is enclosed)
--- kernel/cpu.c-old    2008-07-30 12:31:15.000000000 +0200
+++ kernel/cpu.c        2008-07-30 12:32:02.000000000 +0200
@@ -349,6 +349,8 @@ static int __cpuinit _cpu_up(unsigned in
                goto out_notify;
        BUG_ON(!cpu_online(cpu));

+       cpu_set(cpu, cpu_active_map);
+
        /* Now call notifier in preparation. */
        raw_notifier_call_chain(&cpu_chain, CPU_ONLINE | mod, hcpu);

@@ -383,9 +385,6 @@ int __cpuinit cpu_up(unsigned int cpu)

        err = _cpu_up(cpu, 0);

-       if (cpu_online(cpu))
-               cpu_set(cpu, cpu_active_map);
-
 out:
        cpu_maps_update_done();
        return err;


-- 
Best regards,
Dmitry Adamushko

View attachment "move-cpu_set-cpu_active_map.patch" of type "text/x-patch" (554 bytes)

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