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

From: Haiyang Zhang
Date: Mon Jul 14 2014 - 18:40:31 EST


> -----Original Message-----
> From: Sitsofe Wheeler [mailto:sitsofe@xxxxxxxxx]
> Sent: Monday, July 14, 2014 5:31 PM
> To: Haiyang Zhang
> Cc: KY Srinivasan; David S. Miller; devel@xxxxxxxxxxxxxxxxxxxxxx; linux-
> kernel@xxxxxxxxxxxxxxx; netdev@xxxxxxxxxxxxxxx
> Subject: Re: [BISECTED][REGRESSION] Loading Hyper-V network drivers is
> racy in 3.14+ on Hyper-V 2012 R2
>
> On Fri, Jul 11, 2014 at 03:25:11PM +0000, Haiyang Zhang wrote:
> > Since you found the commit b679ef73edc is related to this problem,
> > could you do a simple test:
> > Reduce the receive buffer size back to 2MB, like below, then re-test
> > it, see if the problem goes away?
> > drivers/net/hyperv/hyperv_net.h
> > #define NETVSC_RECEIVE_BUFFER_SIZE (1024*1024*2) /* 2MB
> */
>
> After doing this I was able to reach over 900 reboots where the network
> connected properly.

Thanks for the tests! I will make a patch that can automatically retry
smaller memory allocs when memory is insufficient.

Thanks,
- Haiyang

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