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How to use dbx on AIX?
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kdbx(8) System Manager's Manual kdbx(8) NAME
kdbx - Analyzes running kernels and dump files SYNOPSIS
/usr/bin/kdbx [-dbx dbx-path] -k [dbx-flags] object-file [core-file] DESCRIPTION
The kdbx debugger is a crash analysis and kernel debugging tool; it is an interactive program that serves as a front-end to the dbx debug- ger. The kdbx debugger is extensible, customizable, and insensitive to changes of offsets and sizes of fields in structures. The only dependencies on kernel header files are for bit definitions in flag fields. The kdbx debugger lets you examine either the running kernel or dump files created by the savecore command. In either case, you examine an object file and a core file. For running systems, these files are usually /vmunix and /dev/mem, respectively. Dump files created by savecore are saved in the directory specified by the /sbin/init.d/savecore script. By default, the directory is /var/adm/crash. The kdbx debugger has facilities for interpreting various symbols and data structures. It can format and display the symbols and data structures in the following ways: In a predefined form as specified in the modules that currently accompany the kdbx debugger As defined in user-written source code modules according to a standardized format for the contents of the kdbx modules All dbx commands are available through kdbx using the dbx flag to kdbx. Defaults If you do not specify a core file, kdbx uses the dbx default of /dev/mem. Therefore, you can use kdbx with /vmunix as its only argument to examine an active system. In general, kdbx assumes that addresses are specified in hexadecimal in commands that perform input or output. When you begin a debugging session, kdbx executes the commands in the system initialization file /var/kdbx/SYSTEM.kdbxrc. The initializa- tion file contains setup commands and alias definitions. The Aliases section lists the aliases defined in this file. You can further cus- tomize the kdbx environment by adding commands and aliases to one of the following initialization files: Contains customized commands and alias definitions for a particular system. Contains customized commands and alias definitions for a specific user. Contains customized commands and alias definitions for a specific project. This file must reside in the current working directory when kdbx is invoked. Invocation To use kdbx to examine a running system, issue the following kdbx command: # kdbx -k /vmunix /dev/mem dbx version 3.11.1 Type 'help' for help. stopped at [thread_block:1403 ,0xfffffc000032e3c0] Source not available (kdbx) To use kdbx to examine an object file and core file created by the savecore utility, issue a kdbx command like the following one: # kdbx -k /usr/adm/crash/vmunix.1 /usr/adm/crash/dev/vmcore.1 dbx version 3.11.1 Type 'help' for help. stopped at [thread_block:1403 ,0xfffffc000032e3c0] Source not available (kdbx) In this case, the version number in the bounds file is one. Commands The kdbx debugger provides the following commands: Sets or displays aliases. If you specify the alias command without arguments, kdbx dis- plays all aliases. If you specify only the variable name, the command displays the alias for name, if one exists. If you specify both name and command-string, name is established as an alias for command-string. Sets the context to user's aliases or extension's aliases. This command is used only by extensions. Dumps, in hexadecimal, the contents of the core file starting at start-address and ending before end- address. Passes the variable command-string to dbx. Specifying dbx is optional; if the command is not recognized by kdbx, it is passed to dbx automatically. See the dbx(1) reference page for a complete description of the dbx commands. Displays help text. Executes an exten- sion and gives it control of the kdbx session until it quits. The variable extension specifies the named extension file and passes it arguments as specified by the arg variables. Valid proc flags are as follows: Causes I/O to and from the extension to be displayed on the screen. Used in conjunction with the dbx debugger for debugging extensions. The file in-pipe takes output from the dbx session and directs it as input to the kdbx session. The file out-pipe takes output from the kdbx session and directs it as input to the dbx session. Causes the output of the procedure to be sent to the invoker of the procedure without interpretation as kdbx commands. Used by extensions that execute other extensions to receive the output from the called extension instead of the user receiving it. Causes kdbx to talk to the subprocess through a tty line instead of pipes. If you also specify the -pipe flag, proc ignores it. Displays string on the terminal. If this command is used by an extension, the extension receives no output. Exits the current command loop. If the current command loop is the top level loop that the user is using, kdbx exits. Otherwise, control is given to the next lowest loop. Reads and interprets files as kdbx commands in the context of the current aliases. The -x flag causes commands to be displayed as they are executed. Removes an alias, if any, from name. Predefined kdbx Aliases The following aliases are defined in the kdbx startup file /var/kdbx/system.kdbxrc: ------------------------------------------------------------------- Alias Definition ------------------------------------------------------------------- arp "proc" arp array_action "proc" array_action buf "proc" buf buf_action list_action "struct buf *" b_forw buf buf callout_action list_action "struct callout *" c_next 0 callout cast "proc" cast convert "proc" convert config "proc" config dis "proc" dis echo "proc" echo export "proc" export fields "proc" fields file "proc" file h help inpcb_action list_action "struct inpcb *" inp_next list_action "proc" list_action mount_action list_action "struct mount *" m_next rootfs rootfs mount "proc" mount namecache "proc" namecache ofile "proc" ofile paddr "proc" paddr pcb "proc" pcb pr "proc" printf "proc" printf proc "proc" proc procaddr "proc" procaddr procp "proc" -pipe /tmp/pipein /tmp/pipeout procpd "proc" -debug -pipe /tmp/pipein /tmp/pipeout proc_action list_action "struct proc *" p_nxt 0 allproc ps "dbx" kps sh "proc" -print_output -tty socket "proc" socket sum "proc" sum swap "proc" swap task "proc" task thread "proc" thread u "proc" u ucred "proc" ucred unaliasall "proc" unaliasall vnode "proc" vnode ------------------------------------------------------------------- Extensions For extensions that display addresses as part of their output, some use a shorthand notation for the upper 32-bits of an address to keep the output readable. The following table lists the notation for each address type. ----------------------------------------------------------- Notation Address Type Replaces Example ----------------------------------------------------------- v virtual ffffffff v0x902416f0 k kseg fffffc00 k0x363076f4 u user space 00000000 u0x86406200 ? Unrecognized or random ?0x0033aa24 type ----------------------------------------------------------- The extensions available to kdbx are as follows: Displays the contents of the address resolution protocol (arp) table. If you specify the optional hyphen (-), arp displays the entire arp table; otherwise, arp displays those entries that have nonzero at_iaddr.s_addr and at_flags fields. Performs a command action on each element of an array. This extension allows you to step through any array in the operat- ing system kernel and display specific components or values as described in the list of command flags. The arguments to the array_action extension are as follows: The type of address of the array element. The number of elements in the array. The address of the array. A variable name or a number can be used to specify start_address. The more common syntax or notation used to refer to the start_address is usually of the form &arrayname[0]. Valid flags for the array_action extension are as follows: If you specify the -head flag, kdbx displays the next argument as the table header. If you specify the -size flag, kdbx uses the next argument as the array element size. Otherwise, kdbx calculates the size from the element type. If you specify the -cond flag, kdbx uses the next argument as a filter. The dbx debugger evaluates the condition for each array element, and if it evaluates to TRUE, takes the action on the array element. The same substitutions that are applied to the command are applied to the condition. The name of the kdbx or dbx command that is to be performed on each element of the array. Note that the kdbx debugger includes several aliases, such as file_action, that might be easier to use than directly using the array_action extension. Substitutions similar to printf can be performed on the command for each array element. The possible substitutions are as follows: %a Address of element %c Cast of address to pointer to array element %i Index of element within the array %s Size of element %t Type of pointer to element Displays the buffer table. If no arguments are specified, the buffers on the hash list are displayed. If addresses are specified, the buffers at those addresses are displayed. If you specify the -free flag, kdbx displays all the buf- fers on the free list. If you specify the -all flag, kdbx displays buffers on the hash list first, followed by buffers on the free list. Displays the callout table. Forces dbx to display a piece of memory as a given type. This extension is equivalent to dbx print *((type)address). Displays the configuration of the machine. Converts numbers from one base to another. The -in and -out flags specify the input and output bases, respectively. If you omit -in, kdbx infers the input base from the arguments. The argu- ments can be either numbers or variables. Displays CPU use statistics on a per-CPU basis. If you specify -update, kdbx updates the display every n seconds. Disassembles some number of instructions as specified in the num-instructions instructions starting at start-address. If you omit the number of instructions, kdbx disassembles one instruction. Displays the exported entries that are mounted remotely. Displays the file table. If no addresses are specified, all file entries with nonzero reference counts are dis- played. Otherwise, the file entries at the specified addresses are displayed. Displays the udb and tcb tables. If no arguments are specified, both tables are displayed. If you specify either -udp or -tcp, kdbx displays the corresponding table. If addresses are specified, -udp and -tcp are ignored and the entries at the specified addresses are displayed. Performs some com- mand on each element of a linked list. This extension makes it possible to walk through any linked list in the operating system kernel and display particular components while walking through the linked list. The arguments to the list_action extension are as follows: The type of address of an element in the specified list. The name of the field that points to the next element. The value of the next field that terminates the list. If the list is NULL-terminated, the value of end-addr is 0. If the list is circular, the value of end-addr is equal to start-addr. The address of a list. The address can be specified as a variable name or a number. Valid flags for the list_action extension are as follows: If you specify the -head header flag, kdbx displays the header argument as the table header. If you specify -cond, the next arg is used as a filter. The dbx debugger evaluates the condition for each list element, and if it evaluates to true, takes the action on the list element. The same substitutions that are applied to the command are applied to the condition. The kdbx or dbx command to perform on each element of the list. Note that kdbx includes several aliases, such as file_action, that might be easier to use than directly using the list_action exten- sion. Substitutions similar to printf substitutions are performed on the command for each element. The possible substitutions are as fol- lows: %a Address of element %c Cast of address to pointer to list element %i Index of element within the list %n Name of next field %t Type of pointer to element Displays the static lock type information contained in the lockinfo structures. This extension is available only when the lockmode system attribute is set to four. The -class flag allows you to display information about a particular class of locks. Displays sta- tistics about locks recorded in the lockstats structure. These statistics are dynamic. This extension is available only when the lockmode system attribute is set to four. Statistics displayed include information about the number of instances of a particular lock type, the number of times processes tried to get a lock type, the number of times processes tried and failed to get a particular lock type and the amount of time spent waiting for locks. The flags for the lockstats extension are as follows: Displays the lockstats structures of the specified lock type Displays the lockstats structures associated with the specified CPU Displays the reads, sleeps attributes, and summary of time spent waiting or number of misses Displays summary data for all CPUs and all lock types Displays summary data for all CPUs Updates the display every n seconds Displays the mount table. The -s flag outputs a short form of the table. If addresses are specified, the mount entries at the specified addresses are displayed. Displays the per-processor namecache entries on the system. If no flags are specified, name- cache entries on the primary cpu are displayed. The flags for the namecache extension are as follows: Displays the list of flags, usage information, and tips. Displays the list of flags and usage information. Displays the namecache entries of the global nega- tive namecache list. Displays the namecache entries, including negative namecache entries. Displays the namecache entries on the specified cpu. Displays the namecache entries with the specified vpid. Displays the namecache entries under the directory with the specified dvpid. Displays the namecache entries with the specified name. For example, to see all the negative entries on processor 1: kdbx> namecache -v 0 -p 1 -all To see all the entries with the filename Makefile on processor 2: kdbx> namecache -p 2 -n Makefile Displays the state of the network interfaces. The optional flags for the netstat extension are as follows: Displays the IP and link-level addresses. Displays timer information. Displays network addresses in numeric formal. Displays the number of dropped packets. Displays the files opened by processes. If no arguments are specified, the extension displays the files opened by each process. If you specify either -proc address or -pid pid, kdbx displays the open files of the given process. The -v flag displays more information about the open files. Converts a range of memory to symbolic references. The argument address is the starting address. The argument number-of-longwords is the number of words to dump out. Displays the process control block for a given thread at the specified address. For integer and floating-point registers, only nonzero contents are displayed. Formats one argument at a time to work around the dbx debugger's command length limitation. It also implements the %s string substitution, which the dbx printf command does not. The argument for- mat-string specifies a character string combining literal characters with conversion specifications. Displays the process table. If addresses are specified, the proc structures at the specified addresses are displayed. Otherwise, all proc structures are dis- played. Converts the specified address to a procedure name. Displays the route and Address Resolution Protocol (ARP) tables. The optional flags for the route extension are as follows: Print verbose route or ARP tables. Display network addresses in numeric for- mat. Display route information on all Resource Affinity Domains (RADs). Display ARP tables. Displays the files that are sockets with nonzero reference counts in the file table. Displays a summary of the system. Displays a summary of swap space. Displays the task structures associated with the specified addresses. If no addresses are specified, all tasks are displayed. Displays informa- tion about the threads associated with the specified addresses. If no addresses are specified, all threads are displayed. Displays the stack trace of one or more threads. If you specify thread_address, the extension displays the stack trace of the specified thread. If you omit the argument and all the flags, trace displays the stack trace of all threads. You can specify the following flags: Display the stack trace of the active thread on each CPU. Display the stack trace of all kernel threads. Display the stack trace of all user threads. Display all ucred structures referenced by the buf structures. Display all references to a given ucred structure. Check the reference count of a particular ucred structure. Check the reference count of all ucred structures (mismatch marked by *). Displays a u structure at the address proc-addr. Displays or checks references to ucred structures. If no flags are specified, this extension displays all references to ucred structures on the system. Possible flags are as follows: Display all ucred structures referenced by the proc structures. Display all ucred structures referenced by the uthread structures. Display all ucred structures referenced by the file structures. Display all ucred structures referenced by the buf structures. Display all references to a given ucred structure. Check the reference count of a particular ucred structure. Check the reference count of all ucred structures (mismatch marked by *). Removes all aliases including the predefined aliases described in the Predefined kdbx Aliases section. Displays the vnode table. If no arguments are specified, all ACTIVE vnodes on the system are displayed. ACTIVE means nonzero usecount or nonzero holdcnt. Possible flags are listed as follows: Display INACTIVE (both usecount and holdcnt are zeros) entries in the vnode table. Display ALL (both ACTIVE and INACTIVE) entries in the vnode table. Display all UFS vnodes. Display all NFS vnodes. Display all CDFS vnodes. Display vnode entries of a mounted file system. Display vnode entries of a par- ticular user. Display vnode entries of a particular group. Display related inode/rnode/cdnode information (used with -ufs, -nfs, or -cdfs only). SEE ALSO
Commands: dbx(1), savecore(8) Kernel Debugging Programmer's Guide kdbx(8)
