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icrash(1M)                                                          icrash(1M)



NAME
     icrash - IRIX system crash analysis utility

SYNOPSIS
     icrash [-e cmd] [-f cmdfile] [-n bounds] [-r] [-v] [-w outfile]
            [-S] namelist corefile

DESCRIPTION
     icrash is a hands-on utility that generates detailed kernel information
     in an easy-to-read format.  icrash also provides the ability to generate
     reports about system crash dumps created by savecore(1M).  Depending on
     the type of system crash dump, icrash can create a unique report that
     contains information about what happened when the system crashed.  icrash
     can be run on live systems or with any namelist and corefile specified on
     the command line.

     namelist contains symbol table information needed for symbolic access to
     the system memory image being examined.  The default namelist is /unix,
     which is used when analyzing a live system.  If the memory image being
     analyzed is from a system core dump (vmcore.N.comp), then namelist must
     be a copy of the unix file that was executing at the time of the crash
     (unix.N).

     corefile is a file containing the system memory image.  The default
     corefile is /dev/mem, which provides access to system memory when
     analyzing a live system.  corefile can also be a pathname to a file
     (vmcore.N.comp) produced by the savecore(1M) utility.

     The icrash command has the options listed below.  By default, all
     information is sent to the standard output, unless the -w option is used:

     -e cmd       Specifies on the command line a set of commands that icrash
                  runs automatically. If more than one command is specified,
                  or if there are any command line options, then cmd must be
                  enclosed within quotation marks.

     -f cmdfile   Specifies a cmdfile that contains a set of commands that
                  icrash runs automatically.

     -n bounds    bounds specifies the numeric value associated with a
                  particular namelist/corefile pair.

     -r           Generates a standard report for the namelist and corefile
                  specified.  The reporting style differs slightly depending
                  on the type of system dump being analyzed (panic or NMI).

     -v           Prints the current version number.

     -w outfile   Writes any generated output to outfile.






                                                                        Page 1





icrash(1M)                                                          icrash(1M)



     -S           Suppresses all output except that which comes from icrash
                  commands. Normally used in conjunction with the -e flag.

REPORT USAGE
     In order to generate a crash report, you must invoke the icrash command
     using the -r flag.  For example:

          icrash -r namelist corefile

     This creates an ICRASH CORE FILE REPORT that prints to standard output.
     The resulting report can then be analyzed to determine what type of
     failure caused the system to crash and dump core. Note that you cannot
     use the -r flag to generate a crash report on a live system.

INTERACTIVE USAGE
     Input during an icrash session is of the form:

          command [argument ... ]

     where command is one of the icrash commands described in the COMMANDS
     section of this reference page and argument is qualifying data that
     determines the specific behavior of the icrash command, which kernel
     structure to print, the number of items to display, etc.

     The following options are available to all icrash commands wherever they
     are semantically valid (see the COMMANDS section below).

     -a           Display all entries -- even those that are currently
                  unallocated, on a free list, or have a reference count of
                  zero.

     -f           Display additional (full) information for a structure. Note
                  that information from all of the fields will not necessarily
                  be displayed. Only those fields that are deemed to be most
                  useful to the debugging process. The icrash print command
                  can be used to display the contents of entire kernel
                  structures.

     -n           Follow the links of related kernel structures to their
                  logical conclusion.  For example, when used with the stream
                  command, information for the stdata structure for the stream
                  is displayed, followed by information on each of the queue
                  pairs on the stream.

     -w outfile   Redirect the output of a commands to the named outfile.

     The output from all icrash commands can be piped to various IRIX commands
     in the following manner:

          command [ argument ... ] | shell_command

     Depending on the context of the command, numeric arguments are assumed to



                                                                        Page 2





icrash(1M)                                                          icrash(1M)



     be in a specific radix.  Counts are assumed to be decimal.  Addresses are
     always hexadecimal (with or without a leading 0x).  Table address
     arguments larger than the size of a table are interpreted as hexadecimal
     addresses; those smaller are assumed to be decimal slots in the table.

COMMANDS
     Below is a list of the interactive commands that are included with
     icrash.  Please note that this list can change from one release to the
     next.  To get an on-line list of all the commands available within
     icrash, use the help command.

     addtype namelist [symbol_list]
          Read in all the type definitions from namelist. The object file with
          the desired type definitions in the namelist must be compiled with
          debugging flags turned on (-g). If a data type of a particular name
          is already know by icrash, then icrash will not load that type. Note
          that caution should be used when intermixing 32-bit object namelists
          with this command when debugging 64-bit vmcores and viceversa.

     anon [-a] [-f] [-n] [-w outfile] anon_list
          Display the anon structure located at each virtual address included
          in anon_list. If the -a option is specified, the pfdats in the
          pcache is displayed in ascending order of their page numbers. Use
          the -f option if the command hangs when used with the -a option. The
          -f option displays all the pfdat's in the pcache on a "first-find"
          basis.

     anontree [-a] [-f] [-n] [-w outfile] anon_list
          Display the anon tree structure for each virtual address included in
          anon_list.

     avlnode [-f] [-n] [-w outfile] avlnode_list
          Display the avlnode structure located at each virtual address
          included in avlnode_list. If the -n option is specified, the root of
          the avltree is identified (using the parent pointer contained in the
          avlnode structure) and all the avlnodes in the tree are displayed.

     base numeric_value ...
          Display a number in binary, octal, decimal, and hexadecimal. A
          number in a radix other then decimal should be preceded by a prefix
          that indicates its radix as follows: 0x, hexadecimal; 0, octal; and
          0b, binary.

     config [-f] [-w outfile] [cpu_list]
          Display the board configuration for a system using the information
          contained in the hwgraph.

     ctrace [-a] [-f] [-w outfile] [cpu_list]
          Displays a stack trace for each CPU included in cpu_list. If
          cpu_list is empty and defkthread is set, ctrace displays a stack
          trace for the cpu that defkthread was running on. If defkthread is
          not set, ctrace displays a trace for the cpu dumpproc was running



                                                                        Page 3





icrash(1M)                                                          icrash(1M)



          on. If there isn't any dumpproc, ctrace displays a stack trace for
          the cpu that initiated the dump (based on the SP saved in dumpregs).
          Or, if the -a option is included in the command line, ctrace
          displays a stack trace for each cpu in the system.

     curkthread [-f] [-w outfile]
          Display the process, sthread, or xthread entry for the kthread
          currently running on all CPUs.

     defkthread [-w outfile] [kthread]
          Set the default kthread if one is indicated on the command line.
          Otherwise, display the current value of defkthread. When icrash is
          run against a system core dump, defkthread gets set automatically to
          the kthread that was active when the system panic occurred. When
          icrash is run on a live system, defkthread does not get set.

          The defkthread value is used by icrash in a number of ways. The
          trace command will display a stack trace for the default kthread if
          one is set. Also, the translation of certain kernel virtual
          addresses (primarily those contained in the kernelstack) depend upon
          defkthread being set.

     die [-w outfile] [die_addr]
          Print out a DWARF information entry at a given die_addr.

     dis [-f] [-w outfile] dis_addr [count]
          Display the disassembled code located at dis_addr for count
          instructions. The default count is 1.

     dump [-d] [-o] [-x] [-B] [-D] [-H] [-W] [-w outfile] addr [count]
          Display count values starting at virtual address addr in one of the
          following formats: decimal (-d), octal (-o), or hexadecimal (-x).
          The default format is hexadecimal, and the default count is 1.

     eframe [-w outfile] eframe_addr
          Display the exception frame (containing a register dump, EPC, cause
          register, and status register) located at eframe_addr.

     etrace [-f] [-w outfile] eframe_addr
          Display a stack trace using the PC and SP found in the exception
          frame pointed to by eframe_addr.  The stack address is determined
          using the stack pointer from the exception frame. Note that
          defkthread must be set equal to the appropriate kthread when
          stack_addr is from the kernelstack or when stack_addr is the CPU
          interrupt stack and there is a kthread running on that CPU.

     file [-a] [-f] [-n] [-p proc] [-w outfile] [file_list]
          Display the file structure located at each virtual address included
          in file_list.  If no addresses are specified, display all currently
          open files.  If the -p option is used, display all files opened by
          proc.  proc can be specific as a virtual address or as a process PID
          (preceded by a #).



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icrash(1M)                                                          icrash(1M)



     findsym [-f] [-w outfile] address_list
          Locate the kernel symbol closest to each virtual address contained
          in address_list.

     from cmdfile
          Read in commands from cmdfile and run them as if typed from the
          icrash command line.  Note that the -w option and pipe (|) option
          are not valid options for the from command. These options can,
          however, can be included in the commands contained in cmdfile.

     fstype [-w outfile] [vfssw_list]
          Display the vfssw structure for each entry in vfssw_list.  Entries
          in vfssw_list can take the form of a virtual address or vfssw table
          slot number. If no vfssw entries are specified, display the entire
          vfssw table.

     func [-w outfile] [func_addr]
          Print out information about the function located at func_addr.

     help [all | command_list]
          Display a description of the named commands, including command
          syntax and an overview of how to use the command. The all option
          displays help information for every command.

     history [-w outfile]
          Dump out the last 20 history commands.  You can also use ! to access
          old commands (including !!, !-N, etc.)

     hwpath [-f] [-w outfile] element_lsit
          Display all pathnames from the /hw file system that terminate with
          the names included in element_list, or that contain label names
          included in element_list. If no names are specified, display all
          unique pathnames. Unique pathnames are ones that terminate in a file
          or symbolic link rather than in a directory. When the hwpath command
          is issued with a -f command line option, the vertex handle for each
          element in the path is also displayed. Note that the hwpath command
          provides a view of the the internal hwgraph data structures which
          are are presented to the user via a filesystem-like interface.

     inode [-f] [-w outfile] inode_list
          Display the inode structure located at each virtual address included
          in inode_list.

     inpcb [-f] [-w outfile] inpcb_list
          Display the inpcb structure located located at each virtual address
          included in inpcb_list.

     kthread [-a] [-f] [-w outfile] [kthread_list]
          Display relevant information for each entry in kthread_list. If no
          entries are specified, display information for all active kthreads
          (processes, xthreads, and sthreads). Entries in kthread_list should
          be in the form of a virtual address.



                                                                        Page 5





icrash(1M)                                                          icrash(1M)



     ktrace [-a] [-f] [-w outfile] [kthread_list]
          Displays a stack trace for each kthread included in kthread_list.
          Entries in kthread_list should be in the form of a virtual address.

     lsnode [-f] [-w outfile] lsnode_list
          Display the lsnode structure located at each virtual address
          included in lsnode_list.

     mbuf [-a] [-f] [-n] [-w outfile] mbuf_list
          Display the mbuf structure located at each virtual address included
          in mbuf_list. In irix6.5 the mbuf command when used with the -a
          option will display details of all the mbufs allocated on the system
          along with output similar to the "netstat -m" output on a live
          machine.

     memory [-f] [-w outfile]
          Display information about the memory installed on each node in the
          system. If the memory command is issued with the -f option, display
          information about the memory contained in each memory slot on each
          node.

     mlinfo [-a] [-f] [-n] [-w outfile] mlinfo_list.
          Display information from the ml_info struct for each virtual address
          included in mlinfo_list.

     mntinfo [-f] [-n] [-w outfile] mntinfo_list
          Display the mntinfo structure for each virtual address included in
          mntinfo_list.  The mntinfo contains information about NFS mounted
          file systems.

     mrlock [-f] [-n] [-w outfile] mrlock_list
          Display the mrlock_s structure located at each virtual address
          included in mrlock_list. If the -f command line option is specified,
          display all queues of WAITERS and HOLDERS. If the -n command line
          option is specified (in conjunction with the -f option), then walk
          each queue displaying information on associated kthreads.

     nodepda [-f] [-w outfile] [nodepda_list]
          Display the nodepda_s structure associated with each item in
          nodepda_list. Entries in nodepda_list can take the form of a node ID
          or a virtual address pointing to a nodepda_s struct in memory. If
          nodepda_list is empty, information for all nodes will be displayed.

     outfile [outfile]
          Set outfile (the file where all command output is sent) if outfile
          is indicated.  Otherwise, display the current value of outfile.

     pager [-w outfile] [on | off]
          When pager is on, all command output is piped through pg. When the
          pager is off, all output is printed continuously without page
          breaks. When the pager command is issued without a command line
          option, the current state of the pager is displayed (on or off).



                                                                        Page 6





icrash(1M)                                                          icrash(1M)



          Note that when the pager is on, command output cannot be redirected
          to a pipe.

     pda [-f] [-w outfile] cpu_list
          Display the pda_s structure associated with each item in cpu_list.
          Entries in cpu_list can take the form of a CPU ID or a virtual
          address pointing to a pda_s struct in memory. If cpu_list is empty,
          the pda_s structure for all CPUs will be displayed.

     pde [-w outfile] pde_list
          Display the pde (page descriptor entry) structure located at each
          virtual address included in pde_list.

     pfdat [-a] [-f] [-w outfile] pfdat_list
          Display the pfdat structure located at each virtual address included
          in pfdat_list.  If the -a flag is issued, display all of the pfdat
          structures on the system (one per physical page).

     pid [-a] [-f] [-w outfile] pid_list
          Display the pid_entry structure for each entry in pid_list. Entries
          in pid_list can take the form of a pid table slot number, process
          PID (following a #), or a virtual address. If no entries are
          specified, display all active (in use) pid entries.

     pregion [-a] [-f] [-n] [-p proc] [-w outfile] [-u uthread] [pregion_list]
          Display the pregion structure located at each virtual address
          included in pregion_list. If the -p option is used, display all
          pregions allocated to proc. When used with the -n option display all
          the pde information for the proc or uthread specified with the -p or
          -u options respectively. proc can be specific as a process PID
          (following a #) or virtual address.

     print [-d] [-o] [-x] [-w outfile] expression
          Evaluate expression and print the result. An expression can consist
          of numeric values, operators, kernel variables, typedefs,
          struct/union members, or a combination of above. The following are
          examples of valid expressions:

            (((2*3+4/2)*2+(2/6))/2)

            *((struct socket*)0xa80000001019f2c8)->so_rcv->sb_mb

            (((pte_t*)0xa8000000005ef088)->pte_pfn)<<14|0xa800000000000000

     printd [-w outfile] expression
          The printd command is the same as the print command except that all
          integers are printed as decimal values.

     printo [-w outfile] expression
          The printo command is the same as the print command except that all
          integers are printed as octol values.




                                                                        Page 7





icrash(1M)                                                          icrash(1M)



     printx [-w outfile] expression
          The printx command is the same as the print command except that all
          integers are printed as hexadecimal values.

     proc [-a] [-f] [-w outfile] [proc_list]
          Display the proc structure for each entry in proc_list.  If no
          entries are specified, display all active processes.  Entries in
          proc_list can take the form of a process PID (following a #) or
          virtual address.

     ptov [-w outfile] address_list
          Display all possible virtual address mappings (K0, K1, and K2) for
          each entry in address_list.  Entries in address_list can be a
          hexadecimal physical address or a PFN (following a #).

     queue [-f] [-n] [-w outfile] queue_list
          Display the queue structure located at each virtual address included
          in queue_list.  If the next option (-n) is specified, a linked list
          of queues, starting with each specified queue then following the
          q_next field, is displayed.

     quit Exit icrash.  Note that q prompts for confirmation unless a ! is
          appended to the command line.

     region [-f] [-n] [-p proc] [-w outfile] region_list
          Display the region structure located at each virtual address
          included in region_list. If the -p option is used, display all
          regions allocated to proc. proc can be specific as a process PID
          (following a #) or virtual address.

     report [-w outfile]
          Print out the base report automatically generated by the savecore
          script when the system comes back up after a system crash.

     rnode [-f] [-n] [-w outfile] rnode_list
          Display the rnode structure for each virtual address included in
          rnode_list. The rnode contains information about a virtual node that
          acts as an interface between two NFS systems.

     runq [-f] [-w outfile]
          Display a list of processes currently on the run queue. Using the -f
          option will print out more specific information about the processes.

     sbe [-w outfile]
          Print out the single bit error information for a Challenge or Onyx
          system (including R8K and R10K systems), assuming the right single
          bit flags in the kernel are turned on.

     search [-B] [-D] [-H] [-W] [-w outfile] [-m mask] pattern [address] [length]
          Locate contiguous bytes of memory that match the values contained in
          pattern, beginning at address for length bytes. pattern consists of
          a string of, from one to 256 hexadecimal digits (with no embedded



                                                                        Page 8





icrash(1M)                                                          icrash(1M)



          spaces).  For full word searches (the default), the first word of
          mask is anded (&) with each word of memory and the result compared
          against the first word in pattern (which is also anded with the
          first word of mask). If there is a match, subsequent words in memory
          are compared with their respective words in pattern (if there are
          any) to see if a match exists for the entire pattern. If the -D
          option is issued, the search is conducted on double word boundaries.
          If the -H option is issued, the search is conducted on halfword
          boundaries. If the -B option is issued, the search will be performed
          without regard to double word, word or halfword boundaries. If a
          mask is not specified, mask defaults to all ones for the size of
          pattern. For all but string searches, the number of hex digits
          specified for pattern cannot be less than will fit into the memory
          boundary size specified. For example, patterns for halfword boundary
          searches, must contain (at least) eight hex digits (two per byte).
          Also, any extra digits beyond the specified boundary will be trimmed
          off from the right side of the input line.

          In addition to finding matches for hex values in memory, it is
          possible to search for strings of characters as well. Just begin and
          end the character search pattern with double quotes ("). The ASCII
          value for each character in the string will form the corresponding
          byte values in the search pattern.

          address can be specified as either a virtual address (K0, K1, K2,
          etc.), a physical address, or as a PFN (directly following a pound #
          sign). If no address is specified (or if the one specified does not
          map to a valid physical memory address), address defaults to the K0
          address mapped to the start of physical memory. An optional length
          parameter specifies the number of bytes to search. If length is not
          specified, it will be set equal to the size of physical memory minus
          the starting physical address. Note that length can be specified
          ONLY when an address has been specified.

     sema [-f] [-w outfile] [sema_list]
          Display the sema_s structure located at each virtual address
          included in sema_list. With the -f option a list of waiters, waiting
          on the sema, are displayed.

     sh [command]
          Escape to the shell with no arguments or execute command.  Note that
          it uses your SHELL environment variable to determine which shell to
          use.

     sizeof structure[.field]
          Dump out the size of structure entered on the command line.  The
          value returned will be in bytes. The user can also use a
          structure.field notation in order to find out what the size of a
          field in structure. If the sizeof command is unable to find
          structure or field, then the structure information is not located in
          the symbol table. Also note that the sizeof command only returns the
          size of struct and union types.



                                                                        Page 9





icrash(1M)                                                          icrash(1M)



     slpproc [-w outfile]
          Print out the set of sleeping processes on the system.

     socket [-f] [-n] [-w outfile] [socket_list]
          Display the socket structure for each virtual address included in
          socket_list.  If no entries are specified, display all sockets that
          are currently allocated.  If the next option (-n) is specified, a
          linked list of protocol control block structures associated with
          each socket will also be displayed.

     stack [-w outfile] stack_pointer
          Print out the stack type, stack address, and stack size for a the
          stack stack_pointer is from. If stack_pointer is from a kthread
          stack, then defkthread must be set equal to the address of the
          appropriate kthread.

     stat [-w outfile]
          Display system statistics and the putbuf array, which contains the
          latest messages printed via the kernel printf/cmn_err routines.

     sthread [-a] [-f] [-w outfile] [sthread_list]
          Display relevant information for each entry in sthread_list. If no
          entries are specified, display information for all active sthreads.
          Entries in sthread_list can take the form of a virtual address.

     strace [-a] [-f] [-l] [-w outfile] [pc] [sp] [stack_addr] [level]
          Displays all complete and unique stack traces (containing level or
          more stack frames) from the stack starting at stack_addr. If level
          isn't specified, then each stack trace must have at least five
          frames to be considered valid. Alternately, use a specific pc and sp
          to generate a stack trace from the stack starting at stack_addr. Or,
          when the -l command line option is specified, displays a list of all
          valid kernel code addresses contained in the stack starting at
          stack_addr, along with their location in the stack, source file and
          line number. Or, if the -a option is specified, display ALL traces
          of level or more frames, including invalid traces and duplicate
          (sub) traces. Note that defkthread must be set equal to the kthread
          being analyzed when stack_addr is the kernel stack address or the
          CPU interrupt stack and there is a process running on that CPU. This
          is necessary so that the trace can automatically "jump" from the
          first stack to the kernel stack of the process being analyzed.

     stream [-a] [-f] [-n] [-w outfile] [stream_list]
          Display the stdata structure for each virtual address included in
          stream_list.  If no entries are specified, display all streams that
          are currently allocated.  If the next option (-n) is specified, a
          linked list of queues that are associated with the stream is also
          displayed.

     strings [-w outfile] start_address | symbol [count]
          Display count strings of ASCII characters starting at start_address
          (or address for symbol).



                                                                       Page 10





icrash(1M)                                                          icrash(1M)



     strstat [-f] [-w outfile]
          Display information about streams related resources (streams,
          queues, message blocks, data blocks, and zones).

     struct [-f] [-l] [-n] [-w outfile] struct addr
          Print structure information for struct using the block of memory
          pointed to by addr.

     swap [-f] [-w outfile] [swap_list]
          Dump out the list of swap devices, including the vnodes that are
          represented. The number of pages, number of free pages, number of
          max pages, priority, and device are listed. The -f flag dumps out
          the name of the swapinfo entry as well.

     symbol [-f] [-w outfile] symbol_list
          Displays information about each kernel symbol included in
          symbol_list.

     tcp [-f] [-w outfile] tcpcb_list
          Display the tcpcb structure for each virtual address included in
          tcpcb_list.

     tlbdump [-w outfile] [cpu_list]
          Display TLB information for each CPU indicated in cpu_list.  If no
          CPUs are indicated, TLB information for all CPUs is displayed.

     trace [-a] [-f] [-w outfile] [kthread_list]
          Displays a stack trace for each kthread included in kthread_list. If
          kthread_list is empty and defkthread is set, then a stack trace for
          the default kthread is displayed. If defkthread is not set, then a
          trace will be displayed for the process stored in dumpproc. If there
          isn't any dumpproc, then trace displays a trace for the cpu that
          generated the core dump.

     type [-w outfile] [symbol] | type_addr
          Display the contents of memory starting at addr using the type
          definition type to format the output. Structures, unions, etc. are
          displayed in a manner similar to the way they were originally
          defined. The values contained in the various struct/union members
          are displayed in accordance with their type declarations. For
          example, kernel addresses are displayed as hexadecimal values,
          signed and unsigned integers are displayed as decimal values, etc.
          Struct/union members that are themselves structs or unions are
          expanded in the much the same way. Alternately, if a kernel symbol
          is entered, instead of type_addr, an attempt is made to determine
          the type of the symbol. If the type can be determined, it will be
          displayed as described above.

     unpcb [-f] [-w outfile] [unpcb_list]
          Display the unpcb structure for each virtual address included in
          unpcb_list.




                                                                       Page 11





icrash(1M)                                                          icrash(1M)



     uthread [-f] [-n] [-k] [-S] [-w outfile]  uthread_list
          Display relevant information for each entry in uthread_list. If no
          entries are specified, display information for all active uthreads.
          When the -S command line option is specified, displays a list of all
          siblings for the specified uthread. Entries in uthread_list can take
          the form of a process PID (following a '#'), or virtual address.
          Note that with the PID option, all uthreads that share a specified
          PID will be displayed. When the -k command line option is specified,
          display all uthread_s structs askthread structs.

     vertex [-a] [-f] [-w outfile] [vertex_list]
          Display the graph_vertex_s structure located at each virtual address
          included in vertex_list.

     vfs [-f] [-w outfile] vfs_list
          Display the vfs structure for each virtual address included in
          vfs_list.

     vnode [-a] [-f] [-n] [-w outfile] vnode_list
          Display the vnode structure for each virtual address included in
          vnode_list.

     vproc [-a] [-f] [-n] [-w outfile] vproc_list
          Display the vproc structure for each virtual address included in
          vproc_list.

     vsocket [-a] [-f] [-n] [-w outfile] vsocket_list
          Display the vsocket structure for each virtual address included in
          vsocket_list.

     vtop [-w outfile] address_list
          Display all possible virtual address mappings (K0, K1, and K2) for
          each virtual address in address_list.

     walk [-f] [-l] [-s] [-w outfile] [struct field|offset addr] [addr offset size]
          Walk a linked list of kernel structures or memory blocks. The walk
          command has three modes of operation. By default, output from the
          walk command consists of a linked list of formatted structure
          entries. Each entry contains a single line of output, similar to the
          output of other icrash commands. The list of structures which can be
          displayed in this manner is limited. To see a listing, issue the
          walk (or struct) command with the -l command line option. Note that
          when viewing the list of structures, only those structures marked
          YES in the LINKS column contain links that can be followed. When the
          walk command is issued with the -s option, each structure is
          displayed, in its entirity, in a C-like format. The only limitation
          on which structures can be walked in this manner is that structure
          related information must be contained in the kernel's symbol table.
          Even if information about a structure is not available, it is
          possible to do a hex memory dump of each structure in the list.

          With the first two options outlined above, the structure name, field



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icrash(1M)                                                          icrash(1M)



          name (or byte offset), and next pointer are required. With the third
          option, a start address, byte offset, and struct size are required.

     Examples:
          walk xfs_inode   i_next   a800000000345678
          walk xfs_inode   8        a800000000345678
          walk -s mrlock_s mr_queue a80000000345678
          walk -s mrlock_s 8        a80000000345678
          walk a800000000345678  8  40

     The last example illustrates the use of the walk command to display
     debugging information about a structure even if its type information is
     not found. It does a memory dump of each structure in the list.

     whatis [-a] [-f] [-l] [-w outfile] expression
          Display type specific information for expression (see the print
          command for what constitutes a valid expression). If the -a option
          is specified, display a list of all structures, unions, typedefs and
          variables. When, in conjunction with the -a option, the -f option is
          specified, expand all struct and union definitions to show
          information for each field.

     xthread [-f] [-n] [-k] [-S] [-w outfile]  xthread_list
          Display relevant information for each entry in xthread_list. If no
          entries are specified, display information for all active xthreads.
          Entries in xthread_list can take the form of a virtual address. When
          the -k command line option is specified, display all xthread_s
          structs as kthread structs.

     zone [-a] [-f] [-w outfile] [zone_list]
          Display information about zone memory allocation resources. If the
          -a option is specified, display a list of all zones allocated in the
          system by zone type.

     ? [-w outfile]
          Displays a list of available commands.

NOTES
     Each version of icrash is specific to the OS release that it came from
     and does not necessarily work on any other OS release.  Do not copy
     icrash to any other IRIX system unless the OS versions are identical
     (including patch levels).

     Running icrash on a live system can sometimes generate random results, as
     the information being viewed is volatile at the time it is displayed.

     When running against compressed system crash dumps, an index file will be
     created to allow icrash quick access to compressed pages inside the dump.
     In addition, if an index file exists, icrash will start much more quickly
     against a crash dump.  icrash will always try to write the index file to
     the same directory where the system crash dumps are stored. If the
     directory is not writable, you will see the message:



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icrash(1M)                                                          icrash(1M)



          icrash: save of index "filename" failed: permission denied

     where filename is the name of the index file that icrash tried to create.
     To avoid this, users can create symbolic links to the namelist and
     corefile in a writable directory, and run icrash on the symbolic links.
     The index file will then be created in the writable directory where the
     symbolic links are located.

     The GNU readline library is used by icrash in interactive mode.  Please
     see the GNU General Public License available from the Free Software
     Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

BUGS & ISSUES
     Some icrash commands will not work completely on O2's with the R10000 cpu
     in them. This is because kernel space in the address range 0x800000-
     0x9fffff are not readable to user processes for this hardware
     configuration. The commands that are most affected are the "pfdat" and
     "zone" commands.





































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Typewritten Software • bear@typewritten.org • Edmonds, WA 98026