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Bug 970548 - duplicate chardev reported after chardev-remove
duplicate chardev reported after chardev-remove
Product: Red Hat Enterprise Linux 7
Classification: Red Hat
Component: qemu-kvm (Show other bugs)
Unspecified Unspecified
medium Severity medium
: rc
: ---
Assigned To: Bandan Das
Virtualization Bugs
Depends On:
Blocks: 994891
  Show dependency treegraph
Reported: 2013-06-04 06:01 EDT by Paolo Bonzini
Modified: 2014-06-17 23:29 EDT (History)
10 users (show)

See Also:
Fixed In Version: QEMU 1.5.2
Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of:
: 994891 (view as bug list)
Last Closed: 2014-06-13 06:52:34 EDT
Type: Bug
Regression: ---
Mount Type: ---
Documentation: ---
Verified Versions:
Category: ---
oVirt Team: ---
RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: ---

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Description Paolo Bonzini 2013-06-04 06:01:48 EDT
An error is reported when readding a character device with the same id as a removed one:

(qemu) chardev-add file,path=foo2,id=foo2
(qemu) chardev-remove foo2
(qemu) chardev-add file,path=foo2,id=foo2
Duplicate ID 'foo2' for chardev
Parsing chardev args failed
Comment 2 Min Deng 2013-06-05 07:20:43 EDT
Hi Paolo,
   I can not reproduce it via QMP,my detail steps:
Build info,
1./usr/libexec/qemu-kvm -cpu SandyBridge -M pc-i440fx-1.5 -enable-kvm -m 4G -smp 4,sockets=2,cores=2,threads=1 -no-kvm-pit-reinjection -usb -device usb-tablet,id=input0 -name sluo-test -uuid a5fd4bfe-ccbf-403d-9a26-41b1b3843729 -rtc base=localtime,clock=host,driftfix=slew -device virtio-serial-pci,id=virtio-serial0,max_ports=16,vectors=0,bus=pci.0,addr=0x3 -chardev socket,id=channel1,path=/tmp/helloworld1,server,nowait -device virtserialport,chardev=channel1,name=com.redhat.rhevm.vdsm,bus=virtio-serial0.0,id=port1 -chardev socket,id=channel2,path=/tmp/helloworld2,server,nowait -device virtserialport,chardev=channel2,name=com.redhat.rhevm.vdsm,bus=virtio-serial0.0,id=port2 -drive file=RHEL-Server-7.0-64-virtio-min.qcow2,if=none,id=drive-system-disk,format=qcow2,cache=none,aio=native,werror=stop,rerror=stop -device virtio-blk-pci,bus=pci.0,addr=0x4,drive=drive-system-disk,id=system-disk,bootindex=1 -netdev tap,id=hostnet0,vhost=on,script=/etc/qemu-ifup -device rtl8139,netdev=hostnet0,id=rtl8139-net-pci0,mac=08:2e:5f:0a:0d:a1,bus=pci.0,addr=0x5,bootindex=2 -monitor stdio -vnc :3 -qmp tcp:0:4444,server,nowait


{"return": {}} 


{"return": {}}


{"return": {}}

  I repeated many times but I still can not reproduce,if possible,could you please tell me why it cannot be reproduced via qmp? thanks in advance.

Best Regards,
Comment 3 juzhang 2013-06-05 21:48:17 EDT
Additional infos,

Min can reproduce this issue by using HMP commands? Would you please tell QE what's different between HMP and QMP?  QE are using QMP command for usual testing since upper mgmt are using QMP. Thanks in advance .
Comment 4 Bandan Das 2013-07-17 15:44:55 EDT
The issue here is that the call path to hmp_chardev_remove isn't removing OptsList. The fix is already upstream :

commit 2ea3e2c1e85097c45a882dbc1fbba4a7fdb3ff1c
Author: Markus Armbruster <armbru@redhat.com>
Date:   Thu Jun 27 15:25:12 2013 +0200

    qemu-char: Fix ID reuse after chardev-remove for qapi-based init
    Commit 2c5f488 introduced qapi-based character device initialization
    as a new code path in qemu_chr_new_from_opts().  Unfortunately, it
    failed to store parameter opts in the new chardev.  Therefore,
    qemu_chr_delete() doesn't delete it.  Even though the device is gone,
    its options linger, and any attempt to create another one with the
    same ID fails.
    Cc: qemu-stable@nongnu.org
    Signed-off-by: Markus Armbruster <armbru@redhat.com>
    Reviewed-by: Gerd Hoffmann <kraxel@redhat.com>
    Message-id: 1372339512-28149-1-git-send-email-armbru@redhat.com
    Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

diff --git a/qemu-char.c b/qemu-char.c
index a030e6b..63972ae 100644
--- a/qemu-char.c
+++ b/qemu-char.c
@@ -3219,6 +3219,7 @@ CharDriverState *qemu_chr_new_from_opts(QemuOpts *opts,
         chr = qemu_chr_find(id);
+        chr->opts = opts;
Comment 10 Jun Li 2014-03-13 22:35:42 EDT
Version of component:
(qemu) chardev-add file,path=foo2,id=foo2
(qemu) chardev-remove foo2
(qemu) chardev-add file,path=foo2,id=foo2
Duplicate ID 'foo2' for chardev
Parsing chardev args failed
(qemu) info chardev 
compat_monitor0: filename=stdio

verify this issue:
Version of components:
Steps as comment0, no error will be reported.
(qemu) chardev-add file,path=foo2,id=foo2
(qemu) chardev-remove foo2
(qemu) chardev-add file,path=foo2,id=foo2
(qemu) info chardev 
foo2: filename=file
Based on above test, this issue has been verified.
Comment 12 Ludek Smid 2014-06-13 06:52:34 EDT
This request was resolved in Red Hat Enterprise Linux 7.0.

Contact your manager or support representative in case you have further questions about the request.

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