Hi Herbert,
today i "googled" a bit more and I found this:
https://bugzilla.kernel.org/show_bug.cgi?id=27142
https://lkml.org/lkml/2011/7/19/232
I think this is the problem I have and it's not vServer related.
Thanks for your help
Urban
Urban Loesch wrote:
>
> Hi Herbert,
>
> Herbert Poetzl wrote:
>> On Sat, Aug 06, 2011 at 03:01:27PM +0200, Urban Loesch wrote:
>>
>>
>>> Am 06.08.2011 14:38, schrieb Herbert Poetzl:
>>>> On Sat, Aug 06, 2011 at 02:13:37PM +0200, Urban Loesch wrote:
>>
>>>>> Hi Herbert,
>>>>>> I just tried to pinpoint the location based on my
>>>>>> 2.6.38.8-vs2.3.0.37-rc17 kernel and I suspect that
>>>>>> task_rq(p) is causing this (for certain p), but
>>>>>> I was wondering why your task_rq_lock() is 0xa0
>>>>>> bytes in size, where mine is just 0x65 bytes ...
>>>>>> especially as the task_rq_lock function is quite
>>>>>> compact ...
>>>>>> could you upload the output of the folling commands
>>>>>> for me (executed in the build directory of your
>>>>>> kernel or with the vmlinux object file)
>>>>>> # objdump -t vmlinux | grep task_rq_lock
>>>>> gives me only on line:
>>>> that's fine, nothing more was expected :)
>>
>>>>> /usr/src/linux-2.6.38.8 # objdump -t vmlinux | grep task_rq_lock
>>>>> ffffffff8104ec60 l F .text 000000000000009c task_rq_lock
>>>>>> # objdump -d vmlinux --start-address=0x`objdump -t vmlinux | sed -n
>>>>>> '/task_rq_lock/ {s/ .*//; p}'` | sed '/task>:/ Q'
>>>>> more lines :-)
>>>>> You can download it at http://www.enas.net/objdump.txt
>>>> I copied the interesting part here:
>>
>>>> ffffffff8104ec60<task_rq_lock>:
>>>> ffffffff8104ec60: 55 push %rbp
>>>> ffffffff8104ec61: 48 89 e5 mov %rsp,%rbp
>>>> ffffffff8104ec64: 48 83 ec 20 sub $0x20,%rsp
>>>> ffffffff8104ec68: 48 89 1c 24 mov %rbx,(%rsp)
>>>> ffffffff8104ec6c: 4c 89 64 24 08 mov %r12,0x8(%rsp)
>>>> ffffffff8104ec71: 4c 89 6c 24 10 mov %r13,0x10(%rsp)
>>>> ffffffff8104ec76: 4c 89 74 24 18 mov %r14,0x18(%rsp)
>>>> ffffffff8104ec7b: e8 40 d0 fb ff callq
>>>> ffffffff8100bcc0<mcount>
>>
>>>> this suggests that you have FTRACE enabled in your
>>>> kernel and probably a bunch of related TRACERS
>>
>>>> ffffffff8104ec80: 48 c7 c3 40 3c 01 00 mov $0x13c40,%rbx
>>>> ffffffff8104ec87: 49 89 fc mov %rdi,%r12
>>>> ffffffff8104ec8a: 49 89 f5 mov %rsi,%r13
>>>> ffffffff8104ec8d: ff 14 25 00 34 a1 81 callq
>>>> *0xffffffff81a13400
>>>> ffffffff8104ec94: 48 89 c2 mov %rax,%rdx
>>>> ffffffff8104ec97: ff 14 25 10 34 a1 81 callq
>>>> *0xffffffff81a13410
>>>> ffffffff8104ec9e: 49 89 55 00 mov %rdx,0x0(%r13)
>>>> ffffffff8104eca2: 49 8b 44 24 08 mov 0x8(%r12),%rax
>>>> ffffffff8104eca7: 49 89 de mov %rbx,%r14
>>>> ffffffff8104ecaa: 8b 40 18 mov 0x18(%rax),%eax
>>>> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>>
>>>> this is where your problem happens, and together with
>>>> the information from the original post (which you
>>>> removed) this looks like task_rq looking for a task at
>>>> 0x9066669066666605 which is rather unlikely to be a
>>>> valid address, so to me this looks like some kind of
>>>> memory corruption, maybe caused by a completely
>>>> different subsystem ...
>>
>>>> ffffffff8104ecad: 4c 03 34 c5 00 d4 ab add
>>>> -0x7e542c00(,%rax,8),%r14
>>>> ffffffff8104ecb4: 81
>>>> ffffffff8104ecb5: 4c 89 f7 mov %r14,%rdi
>>>> ffffffff8104ecb8: e8 43 14 54 00 callq
>>>> ffffffff81590100<_raw_spin_lock>
>>>> ffffffff8104ecbd: 49 8b 44 24 08 mov 0x8(%r12),%rax
>>>> ffffffff8104ecc2: 8b 40 18 mov 0x18(%rax),%eax
>>>> ffffffff8104ecc5: 48 8b 14 c5 00 d4 ab mov
>>>> -0x7e542c00(,%rax,8),%rdx
>>>> ffffffff8104eccc: 81
>>>> ffffffff8104eccd: 48 8d 04 13 lea (%rbx,%rdx,1),%rax
>>>> ffffffff8104ecd1: 49 39 c6 cmp %rax,%r14
>>>> ffffffff8104ecd4: 75 18 jne
>>>> ffffffff8104ecee<task_rq_lock+0x8e>
>>>> ffffffff8104ecd6: 4c 89 f0 mov %r14,%rax
>>>> ffffffff8104ecd9: 48 8b 1c 24 mov (%rsp),%rbx
>>>> ffffffff8104ecdd: 4c 8b 64 24 08 mov 0x8(%rsp),%r12
>>>> ffffffff8104ece2: 4c 8b 6c 24 10 mov 0x10(%rsp),%r13
>>>> ffffffff8104ece7: 4c 8b 74 24 18 mov 0x18(%rsp),%r14
>>>> ffffffff8104ecec: c9 leaveq
>>>> ffffffff8104eced: c3 retq
>>>> ffffffff8104ecee: 49 8b 75 00 mov 0x0(%r13),%rsi
>>>> ffffffff8104ecf2: 4c 89 f7 mov %r14,%rdi
>>>> ffffffff8104ecf5: e8 86 14 54 00 callq
>>>> ffffffff81590180<_raw_spin_unlock_irqrestore>
>>>> ffffffff8104ecfa: eb 91 jmp
>>>> ffffffff8104ec8d<task_rq_lock+0x2d>
>>>> ffffffff8104ecfc: 0f 1f 40 00 nopl 0x0(%rax)
>>
>>>> but that's just a wild guess and some hand waving, to
>>>> get better information and more debug info we would
>>>> first need to find a way to trigger this issue within
>>>> a short amount of time, let's say a few minutes up to
>>>> an hour or so ...
>>
>>> I have no idea how can I do this.
>>
>> setup a test system, where you can hit one of your guests
>> (or several of them at once) with artificial stress tests
>> (like a page impression performance test or so) and
>> monitor the kernel output (best via serial console)
>
> I installed a testsystem and installed a fresh new etch vserver with
> apache2.
>
>>
>> compile the kernel with DEBUG_INFO enabled so that we
>> can more precise pinpointing in case of a kernel trace
>
> Kernel I compiled with DEBUG_INFO. Also VSERVER_DEBUG=y is included.
> Now I have to find a way to test the performance...
>
>>
>>>> btw, does it happen on more than one system or is it
>>>> always the same system?
>>
>>> This happend on two of my servers with heavy apache load.
>>> DELL PE R610 and PE R410. Both with 32GB of ram.
>>
>>> The first time was in June on my R410 with kernel
>>> 2.6.38.6-vs2.3.0.37-rc15
>>> It gets me the following error in syslog:
>>
>>> BUG: unable to handle kernel paging request at 00000000801f0f1d
>>> [2472685.774427] IP: [<ffffffff8103695a>] task_rq_lock+0x4a/0xa0
>>> [2472685.774505] PGD 3164b1067 PUD 0
>>> [2472685.774574] Oops: 0000 [#1] SMP
>>> [2472685.774647] last sysfs file: /sys/module/drbd/parameters/cn_idx
>>> [2472685.774716] CPU 9
>>> [2472685.774723] Modules linked in: dca netconsole configfs drbd
>>> lru_cache sch_hfsc ip6_queue act_police cls_flow cls_fw cls_u32
>>> sch_htb sch_ingress sch_sfq xt_realm iptable_raw ip6t_LOG
>>> xt_connlimit ipt_ULOG ipt_REJECT ip6table_raw ipt_REDIRECT ipt_NETMAP
>>> ipt_MASQUERADE ipt_ECN ipt_ecn ipt_CLUSTERIP ipt_ah ipt_addrtype
>>> nf_nat_tftp nf_nat_snmp_basic nf_nat_sip xt_comment nf_nat_pptp
>>> ip6t_REJECT nf_nat_proto_gre nf_nat_irc nf_nat_h323 nf_nat_ftp
>>> nf_nat_amanda xt_recent ip6table_mangle nf_conntrack_ipv6
>>> nf_conntrack_tftp nf_conntrack_sip nf_conntrack_sane
>>> nf_conntrack_proto_udplite nf_conntrack_proto_sctp nf_conntrack_pptp
>>> nf_conntrack_proto_gre nf_conntrack_netlink nf_conntrack_netbios_ns
>>> nf_conntrack_irc nf_conntrack_h323 nf_conntrack_ftp ts_kmp
>>> nf_conntrack_amanda xt_TPROXY nf_tproxy_core nf_defrag_ipv6 xt_time
>>> xt_TCPMSS xt_tcpmss xt_sctp xt_NFLOG nfnetlink_log xt_policy
>>> xt_pkttype xt_physdev xt_owner xt_NFQUEUE xt_multiport ipt_LOG
>>> xt_mark xt_mac xt_limit iptable_nat xt_length xt_iprange nf_nat
>>> xt_helper nf_conntrack_ipv4 xt_hashlimit nf_defrag_ipv4 xt_DSCP
>>> xt_dscp iptable_mangle xt_dccp xt_connmark xt_CLASSIFY xt_tcpudp
>>> xt_state xt_conntrack nf_conntrack nfnetlink iptable_filter ip_tables
>>> ip6table_filter ip6_tables x_tables ipmi_devintf ipmi_si
>>> ipmi_msghandler mptctl psmouse processor joydev serio_raw tpm_tis tpm
>>> i7core_edac pcspkr tpm_bios edac_core dcdbas power_meter button
>>> mptsas mptscsih mptbase usbhid bnx2 scsi_transport_sas hid e1000e
>>> [last unloaded: igb]
>>> [2472685.776398]
>>> [2472685.776459] Pid: 19778, comm: apache2 Not tainted
>>> 2.6.38.6-vs2.3.0.37-rc15-rol-em64t #7 Dell Inc. PowerEdge R410/0N051F
>>> [2472685.776608] RIP: 0010:[<ffffffff8103695a>] [<ffffffff8103695a>]
>>> task_rq_lock+0x4a/0xa0
>>> [2472685.776743] RSP: 0018:ffff880121b75dc8 EFLAGS: 00010082
>>> [2472685.776811] RAX: 00000000801f0f05 RBX: 0000000000011d00 RCX:
>>> 0000000000000040
>>> [2472685.776936] RDX: 0000000000000282 RSI: ffff880121b75e20 RDI:
>>> 00007f4cfa5fd9a0
>>> [2472685.777057] RBP: ffff880121b75de8 R08: dead000000200200 R09:
>>> dead000000100100
>>> [2472685.777178] R10: dead000000200200 R11: dead000000100100 R12:
>>> 00007f4cfa5fd9a0
>>> [2472685.777299] R13: ffff880121b75e20 R14: 0000000000011d00 R15:
>>> 0000000000000000
>>> [2472685.777420] FS: 00007f4cfb0a2730(0000)
>>> GS:ffff8800bf480000(0000) knlGS:0000000000000000
>>> [2472685.777542] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>>> [2472685.777608] CR2: 00000000801f0f1d CR3: 00000002884d7000 CR4:
>>> 00000000000006e0
>>> [2472685.777728] DR0: 0000000000000000 DR1: 0000000000000000 DR2:
>>> 0000000000000000
>>> [2472685.777848] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7:
>>> 0000000000000400
>>> [2472685.777968] Process apache2 (pid: 19778, threadinfo
>>> ffff880121b74000, task ffff8801167114d0)
>>> [2472685.778091] Stack:
>>> [2472685.778150] 00007f4cfa5fd9a0 ffff88044db61eb8 000000000000000f
>>> 0000000000000000
>>> [2472685.778280] ffff880121b75e58 ffffffff81040bd6 ffff880121b75e48
>>> ffffffff81269f47
>>> [2472685.778410] 0000000000000000 ffff88081eaafe30 ffff880121b75e28
>>> 0000000000000282
>>> [2472685.778540] Call Trace:
>>> [2472685.778604] [<ffffffff81040bd6>] try_to_wake_up+0x36/0x310
>>> [2472685.778671] [<ffffffff81269f47>] ? idr_remove+0x187/0x1f0
>>> [2472685.778739] [<ffffffff81040f05>] wake_up_process+0x15/0x20
>>> [2472685.778806] [<ffffffff81231580>] freeary+0x1e0/0x260
>>> [2472685.778872] [<ffffffff81232631>] T.616+0x71/0xf0
>>> [2472685.778939] [<ffffffff8113376b>] ? fput+0x1cb/0x280
>>> [2472685.779005] [<ffffffff81232719>] sys_semctl+0x69/0xa0
>>> [2472685.779074] [<ffffffff81002882>] system_call_fastpath+0x16/0x1b
>>> [2472685.779142] Code: 00 48 c7 c3 00 1d 01 00 49 89 fc 49 89 f5 9c
>>> 58 0f 1f 44 00 00 48 89 c2 fa 66 0f 1f 44 00 00 49 89 55 00 49 8b 44
>>> 24 08 49 89 de <8b> 40 18 4c 03 34 c5 e0 b2 70 81 4c 89 f7 e8 73 93
>>> 4a 00 49 8b
>>> [2472685.779515] RIP [<ffffffff8103695a>] task_rq_lock+0x4a/0xa0
>>> [2472685.779584] RSP <ffff880121b75dc8>
>>> [2472685.779647] CR2: 00000000801f0f1d
>>> [2472685.780031] ---[ end trace 63c260cc5b2dc0a5 ]---
>>
>>> On this server are running 4 vServers (all with debian lenny and
>>> apache installed).
>>> On my PER610 is running only one vServer with debian etch (apache,
>>> php5-fcgi, mysql 5.0).
>>
>> interestingly both kernel traces include sys_semctl, so
>> it might be related to the code handling the semaphores
>> maybe just try to bang on that a little (from inside the
>> guest) to see if something triggers ...
>
> Sorry but I have no idea how I can do that.
>
> Thanks
> Urban
>
>
>>
>> best,
>> Herbert
>>
>>> thanks,
>>> Urban
>>
>>>> best,
>>>> Herbert
>>
>>>>> thanks,
>>>>> Urban
>>
>
Received on Wed Aug 10 15:27:42 2011