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Bug 635537

Summary:	Disable lseek(2) for virtio ports
Product:	Red Hat Enterprise Linux 6	Reporter:	Amit Shah <amit.shah>
Component:	kernel	Assignee:	Amit Shah <amit.shah>
Status:	CLOSED ERRATA	QA Contact:	Virtualization Bugs <virt-bugs>
Severity:	medium	Docs Contact:
Priority:	low
Version:	6.1	CC:	amit.shah, juzhang, llim, mjenner, tburke, virt-maint
Target Milestone:	rc
Target Release:	6.1
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:	kernel-2.6.32-85.el6	Doc Type:	Bug Fix
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2011-05-23 20:52:51 UTC	Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:
Bug Blocks:	580954

Description Amit Shah 2010-09-20 06:09:07 UTC

Description of problem:

virtio ports are not capable of being seeked, being char devices.  Disable the lseek(2) call.

After applying this patch, the lseek(2) call should return -ESPIPE.

Comment 3 RHEL Program Management 2010-10-05 01:51:24 UTC

This request was evaluated by Red Hat Product Management for inclusion
in a Red Hat Enterprise Linux maintenance release. Product Management has 
requested further review of this request by Red Hat Engineering, for potential
inclusion in a Red Hat Enterprise Linux Update release for currently deployed 
products. This request is not yet committed for inclusion in an Update release.

Comment 5 Amit Shah 2010-10-13 05:30:58 UTC

To test:

W/o the patch, lseek in the guest should return a non-error code without having any effect on the chardev.

With this patch, lseek will return -ESPIPE.

Comment 6 Aristeu Rozanski 2010-12-13 15:14:38 UTC

Patch(es) available on kernel-2.6.32-89.el6

Comment 8 juzhang 2011-01-13 12:02:07 UTC

Reproduced on kernel-2.6.32-83.el6 using amit test-virtserial.git.

Step
1.get code form http://fedorapeople.org/gitweb?p=amitshah/public_git/test-virtserial.git;a=summary
  #git://fedorapeople.org/home/fedora/amitshah/public_git/test-virtserial.git
2.slightly modify
3./run-test.sh
file=/home/rhel6.0_64.qcow2,if=none,id=test,boot=on,cache=none,format=qcow2,werror=stop,rerror=stop -device virtio-blk-pci,drive=test -chardev socket,path=/tmp/amit/test0,server,nowait,id=test0 -chardev socket,path=/tmp/amit/test1,server,nowait,id=test1 -chardev socket,path=/tmp/amit/test2,server,nowait,id=test2 -chardev socket,path=/tmp/amit/test3,server,nowait,id=test3 -chardev socket,path=/tmp/amit/test4,server,nowait,id=test4 -device virtio-serial -device virtconsole,chardev=test0,name=console.0 -device virtserialport,chardev=test1,name=test1 -device virtserialport,chardev=test2,name=test2 -device virtserialport,chardev=test3,name=test3 -device virtserialport,chardev=test4,name=test4 -vnc :1 -net none -enable-kvm -m 1G -serial file:/tmp/amit/test-serial.log -monitor unix:/tmp/amit/test-monitor,server,nowait -snapshot -smp 2
Guest is up 1
          test_open_close -  enabled (      open): PASS
          test_open_close -  enabled (     close): PASS
       test_multiple_open -  enabled (  multiple): PASS
      test_sysfs_and_udev -  enabled (      udev): PASS
   test_read_without_host -  enabled (      read): PASS
       test_blocking_read -  enabled (      read): PASS
    test_nonblocking_read -  enabled (      read): PASS
                test_poll -  enabled (   POLLHUP): PASS
                test_poll -  enabled (   POLLOUT): PASS
                test_poll -  enabled (    POLLIN): PASS
                test_lseek -  enabled (     lseek): FAIL  (Expected result: = -29, received result: 20)

Verified on kernel-2.6.32-95.el6 using the same steps
#./run-test.sh
/usr/libexec/qemu-kvm -drive file=/home/rhel6.0_64.qcow2,if=none,id=test,boot=on,cache=none,format=qcow2,werror=stop,rerror=stop -device virtio-blk-pci,drive=test -chardev socket,path=/tmp/amit/test0,server,nowait,id=test0 -chardev socket,path=/tmp/amit/test1,server,nowait,id=test1 -chardev socket,path=/tmp/amit/test2,server,nowait,id=test2 -chardev socket,path=/tmp/amit/test3,server,nowait,id=test3 -chardev socket,path=/tmp/amit/test4,server,nowait,id=test4 -device virtio-serial -device virtconsole,chardev=test0,name=console.0 -device virtserialport,chardev=test1,name=test1 -device virtserialport,chardev=test2,name=test2 -device virtserialport,chardev=test3,name=test3 -device virtserialport,chardev=test4,name=test4 -vnc :1 -net none -enable-kvm -m 1G -serial file:/tmp/amit/test-serial.log -monitor unix:/tmp/amit/test-monitor,server,nowait -snapshot -smp 2
Guest is up 1
          test_open_close -  enabled (      open): PASS
          test_open_close -  enabled (     close): PASS
       test_multiple_open -  enabled (  multiple): PASS
      test_sysfs_and_udev -  enabled (      udev): PASS
   test_read_without_host -  enabled (      read): PASS
       test_blocking_read -  enabled (      read): PASS
    test_nonblocking_read -  enabled (      read): PASS
                test_poll -  enabled (   POLLHUP): PASS
                test_poll -  enabled (   POLLOUT): PASS
                test_poll -  enabled (    POLLIN): PASS
               test_lseek -  enabled (     lseek): PASS

Please note,test_lseek is pass,that's means no means return in -ESPIPE.

Comment 10 juzhang 2011-01-18 02:50:05 UTC

According to comment8,set this issue status as verified.

Comment 11 errata-xmlrpc 2011-05-23 20:52:51 UTC

An advisory has been issued which should help the problem
described in this bug report. This report is therefore being
closed with a resolution of ERRATA. For more information
on therefore solution and/or where to find the updated files,
please follow the link below. You may reopen this bug report
if the solution does not work for you.

http://rhn.redhat.com/errata/RHSA-2011-0542.html