IV51682: DEADLOCK IN UNP_DISCONNECT AND UNP_CONNECT APPLIES TO AIX 6100-08

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• The user application hangs with the following stack :
  
  (0)> f 6238
  pvthread+185E00 STACK:
  [005968A0]slock+0004C0 (09001000A1DC09CC,
  0FFFFFFFFFFFE940 [??])
  [00009558].simple_lock+000058 ()
  [004F9598]unp_disconnect@AF32_12+000318 (??, ??, ??, ??,
  ??)
  [004F6EA8]uipc_usrreq+000BA8 (??, ??, ??, ??, ??)
  [00527BA8]soesend+001928 (??, ??, ??, ??, ??, ??, ??)
  [0053CEC8]esendit+000B48 (??, ??, ??, ??)
  [0053F550]_esendto+0000D0 (??, ??, ??, ??, ??, ??, ??)
  [000038A4]mfspurr_sc_flih01+0000E4 ()
  [kdb_get_virtual_memory] no real storage @
  FFFFFFFFFFFE840
  [90000000010F4B0]090000000010F4B0 ()
  .
  At the same time, other thread will show the following
  stack
  .
  
  (0)> f 10638
  pvthread+298E00 STACK:
  [005968A0]slock+0004C0 (09001000A1CDF73C,
  0FFFFFFFFFFFE900 [??])
  [00009558].simple_lock+000058 ()
  [004FAAF8]unp_connect+000A78 (??, ??)
  [004F71D4]uipc_usrreq+000ED4 (??, ??, ??, ??, ??)
  [00527BA8]soesend+001928 (??, ??, ??, ??, ??, ??, ??)
  [0053CEC8]esendit+000B48 (??, ??, ??, ??)
  [0053F550]_esendto+0000D0 (??, ??, ??, ??, ??, ??, ??)
  [000038A4]mfspurr_sc_flih01+0000E4 ()
  [kdb_get_virtual_memory] no real storage @
  FFFFFFFFFFFE800
  [90000000010F4B0]090000000010F4B0 ()
  [kdb_read_mem] no real storage @ FFFFFFFFFFF8F90
  

Local fix

• N/A
  

Problem summary

• The user application hangs with the following stack :
  
  (0)> f 6238 pvthread+185E00 STACK:   005968A0 slock+0004C0
  (09001000A1DC09CC, 0FFFFFFFFFFFE940  ?? )
   00009558 .simple_lock+000058 ()
   004F9598 unp_disconnect@AF32_12+000318 (??, ??, ??, ??,??)
   004F6EA8 uipc_usrreq+000BA8 (??, ??, ??, ??, ??)
   00527BA8 soesend+001928 (??, ??, ??, ??, ??, ??, ??)
   0053CEC8 esendit+000B48 (??, ??, ??, ??)
   0053F550 _esendto+0000D0 (??, ??, ??, ??, ??, ??, ??)
   000038A4 mfspurr_sc_flih01+0000E4 ()
  .
  At the same time, other thread will show the following stack
  .
  (0)> f 10638 pvthread+298E00 STACK:   005968A0 slock+0004C0
  (09001000A1CDF73C, 0FFFFFFFFFFFE900  ?? )
   00009558 .simple_lock+000058 ()  004FAAF8 unp_connect+000A78
  (??, ??)  004F71D4 uipc_usrreq+000ED4 (??, ??, ??, ??, ??)
   00527BA8 soesend+001928 (??, ??, ??, ??, ??, ??, ??)
   0053CEC8 esendit+000B48 (??, ??, ??, ??)
   0053F550 _esendto+0000D0 (??, ??, ??, ??, ??, ??, ??)
   000038A4 mfspurr_sc_flih01+0000E4 ()  kdb_get_virtual_memory
  no real storage @ FFFFFFFFFFFE800
   90000000010F4B0 090000000010F4B0 ()  kdb_read_mem  no real
  storage @ FFFFFFFFFFF8F90
  

Problem conclusion

• Code is modified to avoid deadlock in the unix domain sockets
  code. Lock order is always maintained while acquiring /
  releaseing both server and client socket's lock. Due to this
  change deadlock is avoided.
  

Temporary fix

Comments

APAR Information

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

  IV47923

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

  U864754

Fix information

• Fixed component name

  AIX 610 STD EDI

• Fixed component ID

  5765G6200

Applicable component levels

• R610 PSY U864754

     UP14/02/17 I 1000