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Bug 595974 - users should get an error message when tired to use one drive for two or more devices via device_add command.
Summary: users should get an error message when tired to use one drive for two or mor...
Keywords:
Status: CLOSED NEXTRELEASE
Alias: None
Product: Red Hat Enterprise Linux 6
Classification: Red Hat
Component: qemu-kvm
Version: 6.0
Hardware: All
OS: Linux
low
medium
Target Milestone: beta
: 6.1
Assignee: Markus Armbruster
QA Contact: Virtualization Bugs
URL:
Whiteboard:
Depends On:
Blocks: 580953
TreeView+ depends on / blocked
 
Reported: 2010-05-26 03:04 UTC by juzhang
Modified: 2013-01-09 22:37 UTC (History)
6 users (show)

Fixed In Version:
Doc Type: Bug Fix
Doc Text:
Clone Of:
Environment:
Last Closed: 2011-02-16 13:29:17 UTC
Target Upstream Version:
Embargoed:

Attachments (Terms of Use)

Description juzhang 2010-05-26 03:04:29 UTC 
Description of problem:
boot guest with drive's id=test,then tried to add virtio-blk-pci device and drive=test via "(qemu) device_add virtio-blk-pci,drive=test" and added successful.however,I probably should get an error message rather than be able to use one drive for two devices.

Version-Release number of selected component (if applicable):
#uname -r
2.6.32-25.el6.x86_64
#rpm -q qemu-kvm
qemu-kvm-0.12.1.2-2.62.el6.x86_64

How reproducible:

Steps to Reproduce:
1.boot guest with drive's id=test 
/usr/libexec/qemu-kvm  -no-hpet -usbdevice tablet -rtc-td-hack -m 2G -smp 2 -drive file=/root/zhangjunyi/RHEL-Server-6.0-64-virtio.qcow2,if=virtio,boot=on,id=test,cache=none,werror=stop,rerror=stop -net nic,vlan=0,macaddr=22:11:22:45:66:22,model=virtio -net tap,vlan=0,script=/etc/qemu-ifup -uuid `uuidgen` -cpu qemu64,+sse2 -balloon none -boot c -monitor stdio -vnc :10
2.add virtio-blk-pci device and drive=test
(qemu) device_add virtio-blk-pci,drive=test
3.add another virtio-blk-pci device and drive=test
(qemu) device_add virtio-blk-pci,drive=test
 
Actual results:
after step3,In guest,fdisk -l, found /dev/vda,/dev/vdb,/dev/vdc.
/dev/vdb and /dev/vdc is as same as /dev/vda.in fact,just one image,that /dev/vda.

Expected results:
users should  get an error message when tired to use one drive for two or more devices via device_add command.one drive, on device.

Additional info:
Comment 2 RHEL Program Management 2010-05-28 10:36:03 UTC 
This request was evaluated by Red Hat Product Management for inclusion in a Red
Hat Enterprise Linux major release.  Product Management has requested further
review of this request by Red Hat Engineering, for potential inclusion in a Red
Hat Enterprise Linux Major release.  This request is not yet committed for
inclusion.
Comment 3 Gerd Hoffmann 2010-05-31 10:13:08 UTC 
Markus, wanna take this?  I think your blockdev patches cover this anyway ...
Comment 4 Markus Armbruster 2010-05-31 11:16:40 UTC 
They do.  Taking the bug.
Comment 6 juzhang 2010-07-12 11:15:00 UTC 
Tested on qemu-kvm-0.12.1.2-2.91.el6.x86_64.

1. boot guest
/usr/libexec/qemu-kvm -m 2G -smp 2 -drive file=/root/zhangjunyi/winxp_32.raw,if=none,id=test,boot=on,cache=none,format=raw -device ide-drive,drive=test -cpu qemu64,+sse2,+x2apic -monitor stdio -boot order=cdn,menu=on -netdev tap,id=hostnet0,vhost=on -device rtl8139,netdev=hostnet0,id=net0,mac=22:11:22:45:66:97 -vnc :10 -qmp tcp:0:4445,server,nowait

2. telnet the qmp server and issue qmp_capabilites
#{"execute":"qmp_capabilities"}

3.hot add driver,id=test1
#{"execute":"__com.redhat_drive_add", "arguments": {"file":"/root/zhangjunyi/test1.qcow2","format":"qcow2","id":"test1"}}

4.hot add device using test1 driver
#{"execute":"device_add","arguments":{"driver":"virtio-blk-pci","drive":"test1","id":"zhang"}}

5.hot add another device using same test1 driver
{"execute":"device_add","arguments":{"driver":"virtio-blk-pci","drive":"test1","id":"zhang2"}}

6.hot del drive zhang
{ "execute": "device_del", "arguments": { "id": "zhang"}}

7. hot del drive zhang2

Results:
After step7,qemu-kvm was abort because of Segmentation fault

gdb) bt
#0  bdrv_delete (bs=0x0) at block.c:652
#1  0x000000000040ec75 in drive_uninit (dinfo=0x1280730) at /usr/src/debug/qemu-kvm-0.12.1.2/vl.c:2127
#2  0x000000000042c0f8 in virtio_blk_exit_pci (pci_dev=0x1b58300) at /usr/src/debug/qemu-kvm-0.12.1.2/hw/virtio-pci.c:602
#3  0x00000000004211d0 in pci_unregister_device (dev=0x1b58300) at /usr/src/debug/qemu-kvm-0.12.1.2/hw/pci.c:729
#4  0x000000000050ea51 in qdev_free (dev=0x1b58300) at /usr/src/debug/qemu-kvm-0.12.1.2/hw/qdev.c:334
#5  0x000000000048fb01 in pciej_write (opaque=<value optimized out>, addr=<value optimized out>, val=<value optimized out>)
    at /usr/src/debug/qemu-kvm-0.12.1.2/hw/acpi.c:752
#6  0x00000000004e1afc in ioport_write (addr=<value optimized out>, val=<value optimized out>) at ioport.c:80
#7  cpu_outl (addr=<value optimized out>, val=<value optimized out>) at ioport.c:210
#8  0x0000000000439288 in kvm_handle_io (env=0x1091f60) at /usr/src/debug/qemu-kvm-0.12.1.2/kvm-all.c:541
#9  kvm_run (env=0x1091f60) at /usr/src/debug/qemu-kvm-0.12.1.2/qemu-kvm.c:975
#10 0x00000000004393e1 in kvm_cpu_exec (env=<value optimized out>) at /usr/src/debug/qemu-kvm-0.12.1.2/qemu-kvm.c:1658
#11 0x000000000043a551 in kvm_main_loop_cpu (_env=0x1091f60) at /usr/src/debug/qemu-kvm-0.12.1.2/qemu-kvm.c:1900
#12 ap_main_loop (_env=0x1091f60) at /usr/src/debug/qemu-kvm-0.12.1.2/qemu-kvm.c:1950
#13 0x00000033d26077e1 in start_thread () from /lib64/libpthread.so.0
#14 0x00000033d1ee151d in clone () from /lib64/libc.so.6



Would you please tell me is same issue or consequence of this issue?if not same issue,please let me know,i will open a new bug.
Comment 7 Markus Armbruster 2010-11-16 18:26:34 UTC 
I'm pretty sure it is.

If a device uses a drive, device_del deletes the drive along with the device.

In your test case, devices "zhang" and "zhang2" both use drive "test1".  That's bad, and this bz is about preventing it.

Step 6 deletes "zhang" and "test1".  This leaves a dangling drive reference in device "zhang2".

Step 7 deletes "zhang2" and (again) "test1".  The latter crashes.
Comment 8 juzhang 2010-11-17 02:00:21 UTC 
(In reply to comment #7)
> I'm pretty sure it is.
> 
> If a device uses a drive, device_del deletes the drive along with the device.
> 
> In your test case, devices "zhang" and "zhang2" both use drive "test1".  That's
> bad, and this bz is about preventing it.
> 
> Step 6 deletes "zhang" and "test1".  This leaves a dangling drive reference in
> device "zhang2".
> 
> Step 7 deletes "zhang2" and (again) "test1".  The latter crashes.

Got it,Thanks for your confirmation
Comment 10 Markus Armbruster 2011-02-15 13:02:53 UTC 
I believe this has been fixed by the patch for bug 654682, which went into qemu-kvm-0.12.1.2-2.142.el6.  Could you please verify?  Thanks!
Comment 11 juzhang 2011-02-16 06:37:47 UTC 
(In reply to comment #10)
> I believe this has been fixed by the patch for bug 654682, which went into
> qemu-kvm-0.12.1.2-2.142.el6.  Could you please verify?  Thanks!

Tested on qemu-kvm-0.12.1.2-2.144.el6 using the steps as same as comment6.
After step5,
{"error": {"class": "PropertyValueInUse", "desc": "Property 'virtio-blk-pci.drive' can't take value 'test1', it's in use", "data": {"device": "virtio-blk-pci", "property": "drive", "value": "test1"}}}

Hi,Markus

  after step5,qemu-kvm prevent another device attach this driver,so,I think this bug has been fixed.what's your opinion?


Best Regards,
Junyi
Comment 12 Markus Armbruster 2011-02-16 07:59:19 UTC 
Your test case looks good, and the error you get in step 5 is what I expect.
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