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Bug 797854 - host can't receive characters if disconnect to TCP socket then re-connect again
Summary: host can't receive characters if disconnect to TCP socket then re-connect again
Keywords:
Status: CLOSED DUPLICATE of bug 702271
Alias: None
Product: Red Hat Enterprise Linux 7
Classification: Red Hat
Component: qemu-kvm
Version: 7.0
Hardware: Unspecified
OS: Linux
low
low
Target Milestone: rc
: ---
Assignee: Amit Shah
QA Contact: Virtualization Bugs
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2012-02-27 11:25 UTC by Chao Yang
Modified: 2014-07-21 12:54 UTC (History)
15 users (show)

Fixed In Version:
Doc Type: Bug Fix
Doc Text:
Clone Of:
Environment:
Last Closed: 2014-07-21 12:54:23 UTC
Target Upstream Version:
Embargoed:

Attachments (Terms of Use)


Links
System ID Private Priority Status Summary Last Updated
Red Hat Bugzilla 909059 0 medium CLOSED Switch to upstream solution for chardev flow control 2021-02-22 00:41:40 UTC

Internal Links: 909059

Description Chao Yang 2012-02-27 11:25:52 UTC 
Description of problem:
boot a guest with TCP socket backend, transmit characters from guest to host via port, host could receive characters. Disconnect netcat in host by ctrl-c, re-connect again, transmit again from guest, host can't receive characters. *Re-send* in guest, host receives the characters.

Version-Release number of selected component (if applicable):
host:
# rpm -q qemu-kvm;uname -r
qemu-kvm-0.12.1.2-2.231.el6.x86_64
2.6.32-235.el6.x86_64
guest:
2.6.32-236.el6.x86_64

How reproducible:
100%

Steps to Reproduce:
1. boot with tcp socket as backend:
-chardev socket,id=charchannel1,host=127.0.0.1,port=5555,server,nowait -device virtserialport,bus=virtio-serial0.0,chardev=charchannel1,id=channel1,name=tcp.com.redhat.rhevm.vdsm
# cat /sys/kernel/debug/virtio-ports/vport0p2 
name: tcp.com.redhat.rhevm.vdsm
guest_connected: 0
host_connected: 0
outvq_full: 0
bytes_sent: 0
bytes_received: 0
bytes_discarded: 0
is_console: no
console_vtermno: 2185810413

2. nc 127.0.0.1 5555
# cat /sys/kernel/debug/virtio-ports/vport0p2 
name: tcp.com.redhat.rhevm.vdsm
guest_connected: 0
host_connected: 1
outvq_full: 0
bytes_sent: 0
bytes_received: 0
bytes_discarded: 0
is_console: no
console_vtermno: 2185810413

3.# echo aaaa > /dev/vport0p2 
# cat /sys/kernel/debug/virtio-ports/vport0p2 
name: tcp.com.redhat.rhevm.vdsm
guest_connected: 0
host_connected: 1
outvq_full: 0
bytes_sent: 5
bytes_received: 0
bytes_discarded: 0
is_console: no
console_vtermno: 2185810413

4.Ctrl-c in host
# cat /sys/kernel/debug/virtio-ports/vport0p2 
name: tcp.com.redhat.rhevm.vdsm
guest_connected: 0
host_connected: 1 <----- expected?
outvq_full: 0
bytes_sent: 5
bytes_received: 0
bytes_discarded: 0
is_console: no
console_vtermno: 2185810413

5.re-connect by nc 127.0.0.1 5555

6.# echo aaaa > /dev/vport0p2 
 # cat /sys/kernel/debug/virtio-ports/vport0p2 
name: tcp.com.redhat.rhevm.vdsm
guest_connected: 0
host_connected: 1
outvq_full: 0
bytes_sent: 10
bytes_received: 0
bytes_discarded: 0
is_console: no
console_vtermno: 2185810413

Actual results:
after step 3, host can receive characters
after step 6, host fails to receive characters for the first time transmission, re-send for the second time, host could receive.

Expected results:


Additional info:
Comment 4 RHEL Program Management 2012-07-10 06:06:15 UTC 
This request was not resolved in time for the current release.
Red Hat invites you to ask your support representative to
propose this request, if still desired, for consideration in
the next release of Red Hat Enterprise Linux.
Comment 5 RHEL Program Management 2012-07-11 02:03:12 UTC 
This request was erroneously removed from consideration in Red Hat Enterprise Linux 6.4, which is currently under development.  This request will be evaluated for inclusion in Red Hat Enterprise Linux 6.4.
Comment 6 Amit Shah 2012-07-23 11:42:34 UTC 
One of the several bugs that need a rewrite of the qemu chardev layer.  Moving to RHEL7.
Comment 10 Amit Shah 2014-07-21 12:54:23 UTC 

*** This bug has been marked as a duplicate of bug 702271 ***
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