14.11.2 Backtrace Support for Thread Debugging

The following commands are available as backtrace support for thread debugging:

bt

The bt command provides the stack trace of the

 

current thread that is being executed or the thread

 

that accepts the signal in case of a core file.

thread apply all bt

You can use the thread apply all bt command

 

to display the backtrace of all threads. The bt

 

command only provides the stack trace of the

 

current thread under execution.

backtrace_other_thread

The backtrace_other_thread command prints

 

the backtrace of all stack frames for a thread with

 

stack pointer SP, program counter PC and address

 

of gr32 in the backing store BSP. This command

 

enables you to view the stack trace when the stack

 

is corrupted. When using this command, you must

 

ensure that the SP, PC, and BSP values are valid.

 

The syntax for the backtrace_other_thread

 

command is as follows:

 

backtrace_other_thread SP PC BSP

14.11.3 Advanced Thread Debugging Support

Advanced thread debugging support is available for multi-threaded applications running on HP-UX 11iv2, or HP-UX 11iv3.

HP WDB 5.5 and later versions provide advanced thread debugging features to display extended information on the state of pthread primitives such as mutexes, read-write locks and conditional variables.

HP WDB 5.6 and later versions provide advanced thread-debugging options to detect the following thread-related conditions:

•The thread attempts to acquire a non-recursive mutex that it currently holds.

•The thread attempts to unlock a mutex or a read-write lock that it has not ac- quired.

•The thread waits (blocked) on a mutex or read-write lock that is held by a thread with a different scheduling policy.

•Different threads non-concurrently wait on the same condition variable, but with different associated mutexes.

•The thread terminates execution without unlocking the associated mutexes or read-write locks.

•The thread waits on a condition variable for which the associated mutex is not locked.

182 HP-UX Configuration-Specific Information