Walking the stack by hand

Let's dig a bit further and find out what the stack looks like. We'll start at the stack pointer stored in the trap registers. %o6 contains the stack pointer we need.

  f0ac9608/16X  0xf0ac9608:     1               0               0               0                   3               1               f015cd94        f016ffac                   fc61607c        80              fc6ca580        1                   19f8309         fc61607c  f0ac9668        f00ee640   f00ee640/i  stubs_common_code+0x6c:         jmpl    %g1, %o7  f0ac9668/16X  0xf0ac9668:     0               f0ac9858        f016b068        fc61607c                   0               f015cd9c        ffffffe0        1424d5e8                   fc61607c        80              fc6ca580        1                   19f8309         fc61607c  f0ac9760        fc606ca0   fc606ca0/i  semctl+0x664:   call    acct + 0x54  f0ac9760/16X  0xf0ac9760:     404000c7        f008534c        fc607824        2                   fc0af000        f027bd44        0               f016ffac                   f0ac9e94        f0ac9920        f0ac9e94        1                   fc607800        fc6ca580  f0ac9858        fc607a14   fc607a14/i  semsys+0x40:    call    semctl  f0ac9858/16X  0xf0ac9858:     404000c0        fc6079d0        f016b068        1a                   0               0               fc03c4c0        fc03c4c0                   f0ac9e94        f0ac9920        0               0                   0               fc607b04  f0ac98b8        f0070898   f0070898/i  syscall+0x3e4:  jmpl    %g1, %o7  f0ac98b8/16X  0xf0ac98b8:     88              1               f01567ac        0                   fc0af000        35              f0ac9994        f0ac99e0                   f0160dec        f0ac9eb4        0               f0ac9e90                   fffffffc        ffffffff  f0ac9938        f0041aa0   f0041aa0/i  _sys_rtt+0x4d8: call    syscall  f0ac9938/16X  0xf0ac9938:     40900082        ef76b254        ef76b258        20                   88              4               7               f0ac9938                   35              0               8d03            1                   8               0  effff138        ef790f04   ef790f04/i  data address not found 

The stack traceback shows that a system call was made that resulted in a call to the semsys() routine.

Did you notice that the $c output did not match the stack traceback output? When looking at system crashes that resulted from a trap, it is important to remember to use the stack pointer in the trap's register. Otherwise, you may not get an accurate picture of the most recent activity.