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Commands Reference, Volume 1

bosdebug Command

Purpose

Enables, disables and/or displays the status information of the system

Syntax

bosdebug [ -I | -D] [ -M [ -S | -s sizelist] [ -n sizelist]] [ -l <file> ] [ -f ]

bosdebug [ -o]

bosdebug [ -L]

Description

The bosdebug command enables, disables, and/or displays the status of debugging features of the system.

-D Causes the kernel debug program to be loaded on each subsequent reboot.
-I Causes the kernel debug program to be loaded and invoked on each subsequent reboot.
-L Displays the current settings for the kernel debug program and the memory overlay detection system. Note that the settings shown will not take effect until after the next time that the bosboot -a and shutdown -r commands are run. This is the default.
-M Causes the memory overlay detection system to be enabled. Memory overlays in kernel extensions and device drivers will cause a system crash.
-n sizelist Has the same effect as the -s option, but works instead for network memory. Each size must be in the range from 32 to 2048, and must be a power of 2. This causes the net_malloc_frag_mask variable of the no command to be turned on during boot.
-o Turns off all debugging features of the system.
-s sizelist Causes the memory overlay detection system to promote each of the specified allocation sizes to a full page, and allocate and hide the next subsequent page after each allocation. This causes references beyond the end of the allocated memory to cause a system crash. sizelist is a list of memory sizes separated by commas. Each size must be in the range from 16 to 2048, and must be a power of 2.
-S Causes the memory overlay detection system to promote all allocation sizes to the next higher multiple of page size (4096), but does not hide subsequent pages. This improves the chances that references to freed memory will result in a crash, but it does not detect reads or writes beyond the end of allocated memory until that memory is freed.
-l <file< Loads a symbol file into kernel for the kdb debugger print facility. Loads the symbols immediately. Do not reboot. A symbol file to print LFS stuctures may be created as follows:
# echo '#include <sys/vnode.h>' < sym.c 
# echo 'main() { ; }' << sym.c 
# cc -g -o sym sym.c -qdbxextra /* for 32 bit kernel */ 
# cc -g -q64 -o sym sym.c -qdbxextra /* for 64 bit kernel */ 
-f Flushes all the symbols (loaded through -l option) from kernel memory. Flushed immediately. Does not require a reboot.

Any changes made by this command will not take effect until the bosboot -a and shutdown -r commands have been run.

Related Infomation

The bosboot command and shutdown command.

Memory Overlay Detection System (MODS) in the AIX 5L Version 5.2 Kernel Extensions and Device Support Programming Concepts.

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