kernel-packages team mailing list archive

[Chris J Arges <1403152@xxxxxxxxxxxxxxxxxx>]

The result of the reverse bisect between v3.17..v3.18 with the reproducer was:
# first bad commit: [34666d467cbf1e2e3c7bb15a63eccfb582cdd71f] netfilter: bridge: move br_netfilter out of the core
If I backport this patch plus 7276ca3f on top of v3.17 I no longer get the hang with the simple reproducer (although I suspect a more elaborate reproducer would still trigger the issue).

This isn't a fix because we obviously have issues in later kernels. The
'unregister_netdevice' message could occur for different code paths
since there could potentially be many paths that modify the refcnt for
the net_device. I'm going to track who is calling 'dev_put' and
'dev_hold' and figure out which code patch is not freeing before we
start unregistering the device. I'll focus in on the reproducer I have
for now, since this seems similar to the 'shutdown containers with
network connections' case.

In addition I'm doing a bisect between earlier versions to see where the
'regression' occured. 3.11 seems to pass without regression for 5
threads / 50 iterations.

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https://bugs.launchpad.net/bugs/1403152

Title:
  unregister_netdevice: waiting for lo to become free. Usage count

Status in The Linux Kernel:
  Unknown
Status in linux package in Ubuntu:
  In Progress
Status in linux source package in Trusty:
  Confirmed
Status in linux source package in Utopic:
  Confirmed

Bug description:
  I currently running trusty latest patches and i get on these hardware
  and software:

  Ubuntu 3.13.0-43.72-generic 3.13.11.11

  processor	: 7
  vendor_id	: GenuineIntel
  cpu family	: 6
  model		: 77
  model name	: Intel(R) Atom(TM) CPU  C2758  @ 2.40GHz
  stepping	: 8
  microcode	: 0x11d
  cpu MHz		: 2400.000
  cache size	: 1024 KB
  physical id	: 0
  siblings	: 8
  core id		: 7
  cpu cores	: 8
  apicid		: 14
  initial apicid	: 14
  fpu		: yes
  fpu_exception	: yes
  cpuid level	: 11
  wp		: yes
  flags		: fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx rdtscp lm constant_tsc arch_perfmon pebs bts rep_good nopl xtopology nonstop_tsc aperfmperf pni pclmulqdq dtes64 monitor ds_cpl vmx est tm2 ssse3 cx16 xtpr pdcm sse4_1 sse4_2 movbe popcnt tsc_deadline_timer aes rdrand lahf_lm 3dnowprefetch arat epb dtherm tpr_shadow vnmi flexpriority ept vpid tsc_adjust smep erms
  bogomips	: 4799.48
  clflush size	: 64
  cache_alignment	: 64
  address sizes	: 36 bits physical, 48 bits virtual
  power management:

  somehow reproducable the subjected error, and lxc is working still but
  not more managable until a reboot.

  managable means every command hangs.

  I saw there are alot of bugs but they seams to relate to older version
  and are closed, so i decided to file a new one?

  I run alot of machine with trusty an lxc containers but only these kind of machines produces these errors, all
  other don't show these odd behavior.

  thx in advance

  meno

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