RE: [hyperv] BUG at drivers/hv/channel.c:462 while changing MTU

[KY Srinivasan]

> -----Original Message-----
> From: Richard Weinberger [mailto:richard.weinberger@xxxxxxxxx]
> Sent: Monday, August 25, 2014 3:48 AM
> To: Sitsofe Wheeler
> Cc: Haiyang Zhang; KY Srinivasan; Greg Kroah-Hartman;
> devel@xxxxxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; Jason Wang;
> Daniel Borkmann; David S. Miller; netdev@xxxxxxxxxxxxxxx
> Subject: Re: [hyperv] BUG at drivers/hv/channel.c:462 while changing MTU
> 
>  via
> 
> 
> On Wed, Aug 20, 2014 at 5:41 AM, Sitsofe Wheeler <sitsofe@xxxxxxxxx>
> wrote:
> > Aug 20 04:04:41 ubuntuhv kernel: [    9.230399] random: nonblocking pool is
> initialized
> > Aug 20 04:04:41 ubuntuhv kernel: [   10.338487] EXT4-fs (sda1): re-
> mounted. Opts: errors=remount-ro
> > Aug 20 04:04:41 ubuntuhv kernel: [   11.099094] hv_storvsc vmbus_0_1:
> cmd 0x85 scsi status 0x2 srb status 0x6
> > Aug 20 04:04:41 ubuntuhv kernel: [   11.099901] hv_storvsc vmbus_0_1:
> cmd 0x85 scsi status 0x2 srb status 0x6
> > Aug 20 04:04:43 ubuntuhv kernel: [   12.999830] psmouse serio1: trackpoint:
> IBM TrackPoint firmware: 0x01, buttons: 0/0
> > Aug 20 03:55:47 ubuntuhv kernel: [   13.003659] input: TPPS/2 IBM
> TrackPoint as /devices/platform/i8042/serio1/input/input4
> > Aug 20 03:57:28 ubuntuhv kernel: [  113.711832] hv_netvsc vmbus_0_14:
> > net device safe to remove Aug 20 03:57:28 ubuntuhv kernel: [
> > 113.713882] hv_netvsc: hv_netvsc channel opened successfully Aug 20
> > 03:57:29 ubuntuhv kernel: [  114.961312] hv_netvsc vmbus_0_14: Send
> > section size: 6144, Section count:2560 Aug 20 03:57:29 ubuntuhv
> > kernel: [  114.962711] hv_netvsc vmbus_0_14: Device MAC
> > 00:15:5d:6f:02:af link state up Aug 20 03:57:34 ubuntuhv kernel: [
> > 120.027718] hv_netvsc vmbus_0_14: net device safe to remove Aug 20
> > 03:57:34 ubuntuhv kernel: [  120.030047] hv_netvsc: hv_netvsc channel
> > opened successfully Aug 20 03:57:34 ubuntuhv kernel: [  120.035422]
> hv_netvsc vmbus_0_14 eth0: unable to establish receive buffer's gpadl Aug
> 20 03:57:34 ubuntuhv kernel: [  120.039778] hv_netvsc vmbus_0_14 eth0:
> unable to connect to NetVSP - 4 Aug 20 03:57:34 ubuntuhv kernel: [
> 120.039818] ------------[ cut here ]------------ Aug 20 03:57:34 ubuntuhv kernel:
> [  120.039832] kernel BUG at drivers/hv/channel.c:504!
> 
> This is one is also a rude BUG_ON:
>         ret = vmbus_post_msg(msg, sizeof(struct
> vmbus_channel_close_channel));
> 
>         BUG_ON(ret != 0);
> 
> vmbus_post_msg() hv_post_message() can easily return !0.
> i.e. if this kmalloc() fails:
>         addr = (unsigned long)kmalloc(sizeof(struct aligned_input),
> GFP_ATOMIC);
>         if (!addr)
>                 return -ENOMEM;

I will submit a patch to handle this case. I suspect though that the original ASSERT at channel.c (line 504)
is not related to kmalloc failing in vmbus_post_msg(). I will also look at that issue as well.

Regards,

K. Y
> 
> --
> Thanks,
> //richard