The netback driver fails to transition from InitWait to Connected after it's been closed once. The reason is that at the moment netdev_state_change is called the interface is still down, so the NETDEV_CHANGE event is not called. This is visible with the xenpv-win drivers by disabling and enabling the adapters repeatedly. Without the patch, the drivers hang about 1 in 50 times (and that is because of some hacks in the drivers; if I make the drivers talk the correct xenbus protocol they will hang 100% of the time). Upstream ties the Connected transition to the completion of the hotplug scripts, so it doesn't have this issue.
Created attachment 413444 [details] patch
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.
in kernel-2.6.18-205.el5 You can download this test kernel from http://people.redhat.com/jwilson/el5 Detailed testing feedback is always welcomed.
Not sure yet what went wrong w/the release script, but that should have been "in kernel-2.6.18-204.el5" (in build 204, not 205).
Tested with: i386 and x86_64 host Win2008-32 guest Win2003-64 guest Component version: xen-3.0.3-120.el5 xenpv-win-1.3.1-1.el5 Steps: 1. install xenpv-win-1.3.1-1 on Windows guest 2. disable then enable the PV NIC from Device Manager 3. repeat step2 Reproduced the bug with kernel-xen-2.6.18-194.el5: For Win2008-32 and Win2003-64 guest, they both take only one disable/enable cycle to make guest hang. Verified the bug with kernel-xen-2.6.18-231.el5: For both guests, disable/enable work smoothly, and after 6 disable/enable cycles the guests still work fine without hang. According to the test result above, set bug to VERIFIED. here steps are referred to https://bugzilla.redhat.com/show_bug.cgi?id=643345
Also verified with kernel-xen-2.6.18-238.el5
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-2011-0017.html