Basic System Problem Analysis - August 2003

Case Study: Hang Memory Dump continued

Now that you have the address of the semaphore you could, for example, use the function

VAINFO to get the BASE_VA (or address) of that semaphore. It is very likely to be a

part of some larger structure. VAINFO could also be used to tell you the OBJ_CLASS

(object class) of the structure it is in. These would be useful data points.

$169 ($35) nmdat > wl vainfo(b.88ae18d0, 'BASE_VA')

$b.88ae0000

$16a ($35) nmdat > wl vainfo(b.88ae18d0, 'OBJECT_CLASS')

$16e

With the object class you can set a filter on the value, $16e and then use the SYMLIST or

SYML command to see what that may be. Object class constants in the OS all begin with

the string OBJCL

$16b ($35) nmdat > env filter '16e'

$16c ($35) nmdat 16e> syml objcl@,,const

OBJCL_TURBO_GLOBAL_CB CONST INTEGER $16e

So the semaphore is in an object whose class is OBJCL_TURBO_GLOBAL_CB.