Re: 4.1 xend not starting - looking for /sys/devices/xen-backend/? Wrong kernel?

[Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>]

On Fri, Apr 01, 2011 at 01:42:03PM -0700, Nathan March wrote:
> Hoping someone can shed some light on this since I'm finding myself very
> confused by a mismatch of documentation on the wiki/mailing lists. Am I
> just using the wrong kernel?
> 
> Trying to start xend 4.1 it just hangs, strace shows this repeating over
> and over:
> 
> 3827  stat("/sys/devices/xen-backend/", 0x7f68b23eb9f0) = -1 ENOENT (No
> such file or directory)
> 3827  stat("/proc/net/dev", {st_mode=S_IFREG|0444, st_size=0, ...}) = 0
> 3827  gettimeofday({1301688232, 369752}, NULL) = 0
> 3827  open("/proc/net/dev", O_RDONLY)   = 19
> 3827  fstat(19, {st_mode=S_IFREG|0444, st_size=0, ...}) = 0
> 3827  fstat(19, {st_mode=S_IFREG|0444, st_size=0, ...}) = 0
> 3827  mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS,
> -1, 0) = 0x7f68b9005000
> 3827  read(19, "Inter-|   Receive               "..., 8192) = 815
> 3827  read(19, "", 7168)                = 0
> 3827  read(19, "", 8192)                = 0
> 3827  close(19)                         = 0
> 3827  munmap(0x7f68b9005000, 4096)      = 0
> 3827  stat("/proc/net/dev", {st_mode=S_IFREG|0444, st_size=0, ...}) = 0
> 3827  gettimeofday({1301688232, 370994}, NULL) = 0
> 3827  open("/proc/net/dev", O_RDONLY)   = 19
> 3827  fstat(19, {st_mode=S_IFREG|0444, st_size=0, ...}) = 0
> 3827  fstat(19, {st_mode=S_IFREG|0444, st_size=0, ...}) = 0
> 3827  mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS,
> -1, 0) = 0x7f68b9005000
> 3827  read(19, "Inter-|   Receive               "..., 8192) = 815
> 3827  read(19, "", 7168)                = 0
> 3827  read(19, "", 8192)                = 0
> 3827  close(19)                         = 0
> 3827  munmap(0x7f68b9005000, 4096)      = 0
> 3827  select(0, NULL, NULL, NULL, {2, 0}) = 0 (Timeout)
> 3827  ioctl(17, SNDCTL_DSP_RESET, 0x7f68b23ebc20) = 0
> 3827  ioctl(17, SNDCTL_DSP_RESET, 0x7f68b23ebc20) = -1 ESRCH (No such
> process)
> 3827  ioctl(17, SNDCTL_DSP_RESET, 0x7f68b23ebcc0) = 0
> 3827  ioctl(17, SNDCTL_DSP_RESET, 0x7f68b23ebc80) = 0
> 3827  gettimeofday({1301688234, 374799}, NULL) = 0
> 
> >From what I can tell on the lists, /sys/devices/xen-backend/ is the new
> location and /sys/bus/xen-backend/ is the old location? Does that mean
> there's a newer dom0 kernel with the correct paths inside of it?
> 
> I've tried stable-2.6.32.x and next-2.6.32 and both give the same
> result. Trying next-2.6.39 resulted in reboot before booting the dom0
> kernel, I haven't debugged that any further yet.

That might be related to how much memory you have. There is a bug that
if you have more than 4GB physical memory it won't boot.
> 
> The xen 4.1 documentation refers you to the 4.0.1 docs and the old
> paravirtops page still has the same content it's had forever, saying
> that Jeremy's stable-2.6.32.x is the recommended release.  Should I be
> using one of Konrad's branches instead?

either one ought to work.
> 
> It seems very strange to me that xen 4.1 would be considered ready &
> released in a state like this, with no clear documentation on what dom0
> to use.

Not sure why it checks /sys/devices/xen-backend/.. have you tried to
use xl instead?