[BISECTED][REGRESSION] Loading Hyper-V network drivers is racy in 3.14+ on Hyper-V 2012 R2

[Sitsofe Wheeler]

On Mon, Jul 07, 2014 at 04:54:20PM +0000, Haiyang Zhang wrote:
> 
> > -----Original Message-----
> > From: Sitsofe Wheeler [mailto:sitsofe at gmail.com]
> > Sent: Sunday, July 6, 2014 4:18 PM
> > To: Haiyang Zhang
> > Cc: KY Srinivasan; David S. Miller; devel at linuxdriverproject.org; linux-
> > kernel at vger.kernel.org; netdev at vger.kernel.org
> > Subject: [BISECTED][REGRESSION] Loading Hyper-V network drivers is racy in
> > 3.14+ on Hyper-V 2012 R2
> > 
> > With the 3.14 kernel Hyper-V no longer reliably enables its
> > networking devices in time on cloud images leading to network
> > devices permanently remaining offline.
> > 
<snip>
> > the system will usually stop rebooting before 20 passes but the most
> > extreme cases were always less than 100. With a pre
> > b679ef73edc251f6d200a7dd2396e9fef9e36fc3 kernel it did over 390
> > passes before I manually stopped it.
> > 
> > Originally filed on https://bugzilla.redhat.com/show_bug.cgi?id=1095387
> > and then on https://bugzilla.kernel.org/show_bug.cgi?id=78771 but without
> > reply...
> > 
> > Might also be related to
> > http://thread.gmane.org/gmane.linux.kernel/1711873/focus=1733398
> > (Regression in hyperv network driver in 3.14).
> 
> What's the memory size assigned to the Linux guest? And, have you seen
> any related messages in the dmesg log after this issue?

(Feel free to trim my emails when replying - it makes it easier to see
your reply :-)

I've had as little as 256 MBytes and as much as 4 GBytes (non-dynamic)
and still seen the issue.

See https://bugzilla.kernel.org/attachment.cgi?id=142201 for a recent
dmesg (an older dmesg snippet can be seen on the Red Hat bugzilla).

-- 
Sitsofe | http://sucs.org/~sits/