[Patch v3 7/7] add a new interface to show the memory usage of 1st kernel

[Atsushi Kumagai]

Hello,

>On 08/26/14 at 08:25am, Petr Tesarik wrote:
>> On Tue, 26 Aug 2014 11:22:47 +0800
>> "bhe at redhat.com" <bhe at redhat.com> wrote:
>>
>> >[...]
>> > Here it use lseek to position, then try to read, and then reading failed
>> > and raised a SIGKILL.
>> >
>> > lseek(3, 8799381360640, SEEK_SET)       = 8799381360640
>> > read(3,  <unfinished ...>
>> > +++ killed by SIGKILL +++
>> > Killed
>>
>> This smells like killed by OOM Killer. Can you check the kernel log if
>> there's anything?
>
>Thanks for notice, it is caused by kernel addr validation check in
>read_kcore. No idea why it happened.

I found a similar bug as below. This bug must be fixed in your environment
since it looks that you use linux 3.17-rc2, but it might help your
investigation.


commit 0ee364eb316348ddf3e0dfcd986f5f13f528f821
Author: Mel Gorman <mgorman at suse.de>
Date:   Mon Feb 11 14:52:36 2013 +0000

    x86/mm: Check if PUD is large when validating a kernel address

    A user reported the following oops when a backup process reads
    /proc/kcore:

     BUG: unable to handle kernel paging request at ffffbb00ff33b000
     IP: [<ffffffff8103157e>] kern_addr_valid+0xbe/0x110
     [...]

     Call Trace:
      [<ffffffff811b8aaa>] read_kcore+0x17a/0x370
      [<ffffffff811ad847>] proc_reg_read+0x77/0xc0
      [<ffffffff81151687>] vfs_read+0xc7/0x130
      [<ffffffff811517f3>] sys_read+0x53/0xa0
      [<ffffffff81449692>] system_call_fastpath+0x16/0x1b


Thanks
Atsushi Kumagai


>[ +35.288439] BUG: unable to handle kernel paging request at
>ffff8800c4000000
>[  +0.011559] IP: [<ffffffff8105870b>] kern_addr_valid+0x15b/0x1b0
>[  +0.010586] PGD 220f067 PUD 2213067 PMD 80000000c4000062
>[  +0.009994] Oops: 0000 [#1] SMP
>[  +0.007782] Modules linked in: xt_CHECKSUM nf_conntrack_netbios_ns
>nf_conntrack_broadcast ipt_MASQUERADE ip6t_REJECT xt_conntrack cfg80211
>rfki
>[  +0.084041] CPU: 2 PID: 1679 Comm: makedumpfile Not tainted 3.17.0-rc2
>#15
>[  +0.012249] Hardware name: Dell Inc. PowerEdge T105 /0J001K, BIOS
>1.4.4 07/30/2009
>[  +0.012991] task: ffff8800c010ae40 ti: ffff880214830000 task.ti:
>ffff880214830000
>[  +0.012886] RIP: 0010:[<ffffffff8105870b>]  [<ffffffff8105870b>]
>kern_addr_valid+0x15b/0x1b0
>[  +0.013860] RSP: 0018:ffff880214833e88  EFLAGS: 00010206
>[  +0.010710] RAX: 00000000c4000000 RBX: 0000000000001000 RCX:
>0000000000000000
>[  +0.012445] RDX: 00000000c4000000 RSI: ffff880000000000 RDI:
>80000000c4000062
>[  +0.012298] RBP: ffff880214833e88 R08: 000000000000000e R09:
>00007fffffffffff
>[  +0.012322] R10: 0000000000000001 R11: 0000000000000246 R12:
>0000000000001000
>[  +0.012316] R13: 00000000022beb10 R14: ffff880214833f50 R15:
>ffff8800c4000000
>[  +0.012308] FS:  00007f0c91ffa740(0000) GS:ffff88022fd00000(0000)
>knlGS:0000000000000000
>[  +0.013315] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>[  +0.010985] CR2: ffff8800c4000000 CR3: 000000021a632000 CR4:
>00000000000007e0
>[  +0.012266] Stack:
>[  +0.006976]  ffff880214833ee0 ffffffff81255c38 ffff880214929410
>0000000000000000
>[  +0.012471]  0000000d14833ed8 0000000000001000 ffff880223c7c480
>00000000022beb10
>[  +0.012465]  ffff880214833f50 0000000000001000 00007ffffe1840c0
>ffff880214833f00
>[  +0.012456] Call Trace:
>[  +0.007459]  [<ffffffff81255c38>] read_kcore+0x228/0x300
>[  +0.010392]  [<ffffffff8124962d>] proc_reg_read+0x3d/0x80
>[  +0.010491]  [<ffffffff811e58f8>] vfs_read+0x98/0x170
>[  +0.010153]  [<ffffffff811e6576>] SyS_read+0x46/0xb0
>[  +0.010034]  [<ffffffff8111d5f6>] ? __audit_syscall_exit+0x1f6/0x2a0
>[  +0.011425]  [<ffffffff8181dea9>] system_call_fastpath+0x16/0x1b
>[  +0.011072] Code: 48 89 f8 66 66 66 90 48 be 00 f0 ff ff ff 3f 00 00
>48 c1 ea 09 48 21 f0 81 e2 f8 0f 00 00 48 be 00 00 00 00 00 88 ff ff 48
>01
>[  +0.030537] RIP  [<ffffffff8105870b>] kern_addr_valid+0x15b/0x1b0
>[  +0.011666]  RSP <ffff880214833e88>
>[  +0.009043] CR2: ffff8800c4000000
>[  +0.042194] ---[ end trace 97512601fec12186 ]---
>
>_______________________________________________
>kexec mailing list
>kexec at lists.infradead.org
>http://lists.infradead.org/mailman/listinfo/kexec