3704060 - A memory dump encounters timeslice on 'write' call when writing error log to the dump - SAP ASE

• After taking a successful memory dump
• The ASE error log reports a timeslice when appending the error log to the dump file
• The stack for the timeslice includes functions write and shm_update_errorlog
• A typical log sequence includes these elements
  
  
  • the event that triggers a memory dump , for example
    
    00:0003:00000:01064:2026/01/05 05:10:31.94 kernel  Current process (0x1c8f0488) infected with signal 11 (SIGSEGV)
    00:0003:00000:01064:2026/01/05 05:10:31.94 kernel  Address 0x0x00000000016b68c8 (Optimize+0xe68), siginfo (code, address) = (128, 0x(nil))
    ...
    00:0003:00000:01064:2026/01/05 05:10:31.94 server  Initiating shared memory dump for signal 11
    ...
    00:0003:00000:01064:2026/01/05 05:11:00.30 server  Shared memory dump completed successfully
    ...
    00:0003:00000:01064:2026/01/05 05:11:00.30 kernel  end of stack trace, spid 1064, kpid 479134856, suid 43
    
    
  • a message after that shows the errorlog is written to the memory dump file (note the time):
    
    00:0003:00000:01064:2026/01/05 05:11:00.32 kernel  Updating errorlog in dump file /tmp/MEMDUMP_ASE/ASE.dmp.2026010409172901 (13626 MB).
    
    
  • followed by a timeslice at 'write' function call
  • at a time exactly equivalent to the 'cpu grace time' value of the server
  • in this example, that value is 500 which is 50 seconds, so the message is seen 50 seconds later than the highlighted time above
    
    00:0003:00000:01064:2026/01/05 05:11:50.32 kernel  timeslice -501, current process infected at 0x2b9c75ba26fd (write+0x2d)
    ...
    00:0003:00000:01064:2026/01/05 05:12:23.87 kernel  Dump complete in 34 seconds.
    00:0003:00000:01064:2026/01/05 05:12:23.87 kernel  6 segments of total size 14212284416 bytes written to dump file.
    00:0003:00000:01064:2026/01/05 05:12:23.87 server  Shared memory dump completed successfully.
    
    
  • with stack functions:
    
    null
    shm_update_errorlog
    kisignal
    write

SAP Adaptive Server Enterprise (ASE) 16.0 SP04 & 16.1

(null) , (null)+0x2b9c75ba3630() , shm_update_errorlog+0x179() , kisignal+0xac7() , write+0x2d() , KBA , BC-SYB-ASE , Sybase ASE Database Platform (non Business Suite) , BC-DB-SYB , Business Suite on Adaptive Server Enterprise , Known Error