[ktap] Re: "BUG: unable to handle kernel paging request" after ktap script to trace SyS_write
- From: Azat Khuzhin <a3at.mail@xxxxxxxxx>
- To: ktap@xxxxxxxxxxxxx
- Date: Sun, 20 Oct 2013 18:22:11 +0400
On Sun, Oct 20, 2013 at 12:50 PM, Jovi Zhangwei <jovi.zhangwei@xxxxxxxxx> wrote:
> On Sat, Oct 19, 2013 at 5:06 PM, Azat Khuzhin <a3at.mail@xxxxxxxxx> wrote:
>> Hi all,
>>
>> I used next script, and after a few seconds of working, I have all ssh
>> sessions killed.
>> #! /usr/bin/env ktap
>> trace probe:SyS_write {
>> print(backtrace(0, 100))
>> }
>>
>> However, I can login after this, and have next messages in dmesg:
>>
> Hi Azat,
Hi Jovi,
>
> Thanks for your reporting, could you help to check if below two
> scripts works correctly?
>
> #! /usr/bin/env ktap
> trace probe:SyS_write {
> print_backtrace(0, 100)
> }
[ 107.416689] BUG: unable to handle kernel paging request at ffffffff621ee2b5
[ 107.417774] IP: [<ffffffff621ee2b5>] 0xffffffff621ee2b4
[ 107.418569] PGD 160c067 PUD 0
[ 107.419409] Oops: 0010 [#3] PREEMPT SMP
[ 107.420038] Modules linked in: ktapvm(O) nfsd auth_rpcgss
oid_registry nfs_acl nfs lockd fscache sunrpc loop fuse joydev
hid_generic usbhid hid snd_pcm microcode snd_page_alloc snd_timer snd
soundcore ohci_pci ohci_hcd ehci_hcd psmouse usbcore i2c_piix4
processor ac ther
mal_sys serio_raw pcspkr parport_pc usb_common evdev parport button
i2c_core ext4 crc16 jbd2 mbcache sd_mod sg crc_t10dif sr_mod cdrom
crct10dif_common ata_generic ahci libahci ata_piix libata e1000
scsi_mod
[ 107.420038] CPU: 1 PID: 2654 Comm: less Tainted: G D O
3.12.0-rc5+ #40
[ 107.420038] Hardware name: innotek GmbH VirtualBox/VirtualBox, BIOS
VirtualBox 12/01/2006
[ 107.420038] task: ffff88007a911790 ti: ffff88007a05c000 task.ti:
ffff88007a05c000
[ 107.420038] RIP: 0010:[<ffffffff621ee2b5>] [<ffffffff621ee2b5>]
0xffffffff621ee2b4
[ 107.420038] RSP: 0018:ffff88007a05df78 EFLAGS: 00010293
[ 107.420038] RAX: 0000000000000001 RBX: 00000000000003ff RCX: 0000000000000001
[ 107.420038] RDX: 00000000000003ff RSI: 0000000000628940 RDI: 0000000000000001
[ 107.420038] RBP: 000000000000005f R08: 0000000001e49c20 R09: 0000000000000000
[ 107.420038] R10: 0000000000000001 R11: 0000000000000246 R12: 0000000000000000
[ 107.420038] R13: 0000000000000043 R14: 0000000000000000 R15: 0000000000000000
[ 107.420038] FS: 00007ff4a1bda700(0000) GS:ffff88007fd00000(0000)
knlGS:0000000000000000
[ 107.420038] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b
[ 107.420038] CR2: ffffffff621ee2b5 CR3: 000000007b91a000 CR4: 00000000000006e0
[ 107.420038] Stack:
[ 107.420038] 000000000000005f ffffffff813b2b22 0000000000000246
0000000000000001
[ 107.420038] 0000000000000000 0000000001e49c20 0000000000000001
0000000000000023
[ 107.420038] 00000000000003ff 0000000000628940 0000000000000001
0000000000000001
[ 107.420038] Call Trace:
[ 107.420038] [<ffffffff813b2b22>] ? system_call_fastpath+0x16/0x1b
[ 107.420038] Code: Bad RIP value.
[ 107.420038] RIP [<ffffffff621ee2b5>] 0xffffffff621ee2b4
[ 107.420038] RSP <ffff88007a05df78>
[ 107.420038] CR2: ffffffff621ee2b5
[ 107.420038] ---[ end trace fe1cc133ae0119a3 ]---
And others.
>
>
> #! /usr/bin/env ktap
> trace probe:schedule {
> print(backtrace(0, 100))
> }
This one printed message about 10 tines
and after this system hangs.
In debugger attached to kernel:
Program received signal SIGSEGV, Segmentation fault.
>
> Thanks.
>
> Jovi
>
--
Respectfully
Azat Khuzhin
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