IV84544: ETHERCHANNEL WITH CT3 ADAPTER MAY HANG APPLIES TO AIX 7100-04

APAR status

• Closed as program error.

Error description

• There is a deadlock kind of situation in the routines
  rrent_output and ethchan_link_status_callback_func
  resulting
  in lock contention problems among some threads making all
  the
  LPAR's inaccessible.
  
  Call stacks of these CPU's are as follows:
  
  --- CPU #0 ---
  pvthread+00AA00 STACK:
  ?005983D4?drw_lock_write+000114 (0000000000000001 ????)
  ?00014F50?.kernel_add_gate_cstack+000030 ()
  ?F1000000C05D5D74?ethchandd:ethchan_link_status_callback_
  func+000094
     (??, ??, ??)
  ?00014D70?.hkey_legacy_gate+00004C ()
  ?047E57CC?rrentdd:rrent_event_notify+000B4C (??, ??, ??)
  ?047E11F8?rrentdd:librrhba_user_errproc+0004F8 (??, ??,
  ??)
  ?0020A1F0?procentry+000010 (??, ??, ??, ??)
  ?kdb_read_mem? no real storage @ FFFFFFFFFFF8900
  .
  --- CPU #8 ---
  pvthread+00C600 STACK:
  ?0059B270?slock+000330 (0000000002C70000,
  0000000000001000 ????)
  ?000090C4?.disable_lock+0000C0 ()
  ?047EBA60?rrentdd:rrent_output+0002C0 (??, ??)
  ?F1000000C05D7A7C?ethchandd:ethchan_output+0002FC (??,
  ??)
  ?F1000000C0601BE8?seadd:sea_virt_input_post_q+000728
  (F1000A0035AC0000,
     F1000A0029E1A6E8, F1000E000018B600)
  ?F1000000C0600AA8?seadd:sea_send_packet+000108 (??, ??,
  ??)
  ?F1000000C0600068?seadd:sea_thread+0002A8 (??)
  ?00014D70?.hkey_legacy_gate+00004C ()
  ?003BC0D4?threadentry+000094 (??, ??, ??, ??)
  ?kdb_read_mem? no real storage @ FFFFFFFFFFF8900
  .
  --- CPU #12 ---
  pvthread+00C500 STACK:
  ?005949F4?drw_lock_read_ppc+000954 (F1000A00356A3448
  ????)
  ?F1000000C05D7848?ethchandd:ethchan_output+0000C8 (??,
  ??)
  ?F1000000C0601BE8?seadd:sea_virt_input_post_q+000728
  (F1000A0035AC0000,
     F1000A0029E1A6E8, F1000E00011BD200)
  ?F1000000C0600AA8?seadd:sea_send_packet+000108 (??, ??,
  ??)
  ?F1000000C0600068?seadd:sea_thread+0002A8 (??)
  ?00014D70?.hkey_legacy_gate+00004C ()
  ?003BC0D4?threadentry+000094 (??, ??, ??, ??)
  ?kdb_read_mem? no real storage @ FFFFFFFFFFF8900
  .
  CPU 8 is spinning in slock code for lock
  F1000A002BE5D600.
  .
  (8)> slk @r31
  F1000A002BE5D600
  krlock association: kp:F1000A03F00F5F00 : 1
  total threads contending: 00000001
  gp:0: F1000A03F00F6F00 :
  krl owner: 8
   lock FE00100000AA005D
   thread_owner............ 00AA005D @ pvthread+00AA00
  (8)> status | grep AA005D
    0         AA005D    170  5600B4     86
  librrhba_errproc
  (8)>
  .
  CPU 0 is in drw_lock_write code and the lock address
  passed to
  drw_lock_write was F1000A00356A3448. In cpu 12,the call
  stack
  includes drw_lock_read_ppc and the lock address passed is
  the same i.e. F1000A00356A3448.
  

Local fix

Problem summary

• Etherchannel over CT3 adapter may result in hang situation
  due to deadlock between rrent_output function and
  ethchan_link_status_callback_func function.
  

Problem conclusion

• CT3 driver code is modified to fix the lock contention problem.
  

Temporary fix

Comments

• 6100-09 - use AIX APAR IV76243
  6100-09 - use AIX APAR IV76243
  7100-04 - use AIX APAR IV84544
  7200-01 - use AIX APAR IV84650
  

APAR Information

• APAR is sysrouted FROM one or more of the following:

  IV76243

• APAR is sysrouted TO one or more of the following:

Fix information

• Fixed component name

  AIX V7.1

• Fixed component ID

  5765H4000

Applicable component levels

• R710 PSY U869863

     UP16/10/25 I 1000