2 .\" Mach Operating System
3 .\" Copyright (c) 1991,1990 Carnegie Mellon University
4 .\" Copyright (c) 2007 Robert N. M. Watson
5 .\" All Rights Reserved.
7 .\" Permission to use, copy, modify and distribute this software and its
8 .\" documentation is hereby granted, provided that both the copyright
9 .\" notice and this permission notice appear in all copies of the
10 .\" software, derivative works or modified versions, and any portions
11 .\" thereof, and that both notices appear in supporting documentation.
13 .\" CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
14 .\" CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
15 .\" ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
17 .\" Carnegie Mellon requests users of this software to return to
19 .\" Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
20 .\" School of Computer Science
21 .\" Carnegie Mellon University
22 .\" Pittsburgh PA 15213-3890
24 .\" any improvements or extensions that they make and grant Carnegie Mellon
25 .\" the rights to redistribute these changes.
27 .\" changed a \# to #, since groff choked on it.
31 .\" Revision 1.1 1993/07/15 18:41:02 brezak
34 .\" Revision 2.6 92/04/08 08:52:57 rpd
36 .\" [92/01/17 14:19:22 jsb]
37 .\" Changes for OSF debugger modifications.
40 .\" Revision 2.5 91/06/25 13:50:22 rpd
41 .\" Added some watchpoint explanation.
44 .\" Revision 2.4 91/06/17 15:47:31 jsb
45 .\" Added documentation for continue/c, match, search, and watchpoints.
46 .\" I've not actually explained what a watchpoint is; maybe Rich can
47 .\" do that (hint, hint).
48 .\" [91/06/17 10:58:08 jsb]
50 .\" Revision 2.3 91/05/14 17:04:23 mrt
51 .\" Correcting copyright
53 .\" Revision 2.2 91/02/14 14:10:06 mrt
54 .\" Changed to new Mach copyright
55 .\" [91/02/12 18:10:12 mrt]
57 .\" Revision 2.2 90/08/30 14:23:15 dbg
68 .Nd interactive kernel debugger
70 In order to enable kernel debugging facilities include:
71 .Bd -ragged -offset indent
76 To prevent activation of the debugger on kernel
78 .Bd -ragged -offset indent
79 .Cd options KDB_UNATTENDED
82 In order to print a stack trace of the current thread on the console
84 .Bd -ragged -offset indent
88 To print the numerical value of symbols in addition to the symbolic
89 representation, define:
90 .Bd -ragged -offset indent
91 .Cd options DDB_NUMSYM
96 backend, so that remote debugging with
99 .Bd -ragged -offset indent
105 kernel debugger is an interactive debugger with a syntax inspired by
107 If linked into the running kernel,
108 it can be invoked locally with the
112 The debugger is also invoked on kernel
115 .Va debug.debugger_on_panic
117 MIB variable is set non-zero,
123 The current location is called
128 a hexadecimal format at a prompt.
135 to the address of the last line
136 examined or the last location modified, and set
139 the next location to be examined or changed.
140 Other commands do not change
147 The general command syntax is:
148 .Ar command Ns Op Li / Ns Ar modifier
149 .Ar address Ns Op Li , Ns Ar count
151 A blank line repeats the previous command from the address
154 count 1 and no modifiers.
167 to be 1 for printing commands or infinity for stack traces.
171 debugger has a pager feature (like the
175 If an output line exceeds the number set in the
177 variable, it displays
179 and waits for a response.
180 The valid responses for it are:
182 .Bl -tag -compact -width ".Li SPC"
188 abort the current command, and return to the command input mode
193 provides a small (currently 10 items) command history, and offers
196 command line editing capabilities.
200 control keys, the usual
202 arrow keys may be used to
203 browse through the history buffer, and move the cursor within the
206 .Bl -tag -width indent -compact
209 Display the addressed locations according to the formats in the modifier.
210 Multiple modifier formats display multiple locations.
211 If no format is specified, the last format specified for this command
214 The format characters are:
215 .Bl -tag -compact -width indent
217 look at by bytes (8 bits)
219 look at by half words (16 bits)
221 look at by long words (32 bits)
223 print the location being displayed
225 print the location with a line number if possible
227 display in unsigned hex
229 display in signed hex
231 display in unsigned octal
233 display in signed decimal
235 display in unsigned decimal
237 display in current radix, signed
239 display low 8 bits as a character.
240 Non-printing characters are displayed as an octal escape code (e.g.,
243 display the null-terminated string at the location.
244 Non-printing characters are displayed as octal escapes.
246 display in unsigned hex with character dump at the end of each line.
247 The location is also displayed in hex at the beginning of each line.
249 display as an instruction
251 display as an instruction with possible alternate formats depending on the
253 .Bl -tag -width ".Tn powerpc" -compact
266 display a symbol name for the pointer stored at the address
273 command with the last specified parameters to it
274 except that the next address displayed by it is used as the start address.
280 command with the last specified parameters to it
281 except that the last start address subtracted by the size displayed by it
282 is used as the start address.
284 .It Ic print Ns Op Li / Ns Cm acdoruxz
285 .It Ic p Ns Op Li / Ns Cm acdoruxz
288 according to the modifier character (as described above for
291 .Cm a , x , z , o , d , u , r ,
294 If no modifier is specified, the last one specified to it is used.
297 can be a string, in which case it is printed as it is.
299 .Bd -literal -offset indent
300 print/x "eax = " $eax "\enecx = " $ecx "\en"
304 .Bd -literal -offset indent
310 .Ic write Ns Op Li / Ns Cm bhl
311 .Ar addr expr1 Op Ar expr2 ...
314 .Ic w Ns Op Li / Ns Cm bhl
315 .Ar addr expr1 Op Ar expr2 ...
317 Write the expressions specified after
319 on the command line at succeeding locations starting with
321 The write unit size can be specified in the modifier with a letter
327 (long word) respectively.
329 long word is assumed.
332 since there is no delimiter between expressions, strange
334 It is best to enclose each expression in parentheses.
336 .It Ic set Li $ Ns Ar variable Oo Li = Oc Ar expr
337 Set the named variable or register with the value of
339 Valid variable names are described below.
341 .It Ic break Ns Op Li / Ns Cm u
342 .It Ic b Ns Op Li / Ns Cm u
347 is supplied, continues
349 \- 1 times before stopping at the
351 If the break point is set, a break point number is
354 This number can be used in deleting the break point
355 or adding conditions to it.
359 modifier is specified, this command sets a break point in user
363 option, the address is considered to be in the kernel
364 space, and a wrong space address is rejected with an error message.
365 This modifier can be used only if it is supported by machine dependent
369 If a user text is shadowed by a normal user space debugger,
370 user space break points may not work correctly.
372 point at the low-level code paths may also cause strange behavior.
374 .It Ic delete Ar addr
376 .It Ic delete Li # Ns Ar number
377 .It Ic d Li # Ns Ar number
378 Delete the break point.
379 The target break point can be specified by a
380 break point number with
384 specified in the original
388 .It Ic watch Ar addr Ns Li , Ns Ar size
389 Set a watchpoint for a region.
390 Execution stops when an attempt to modify the region occurs.
393 argument defaults to 4.
394 If you specify a wrong space address, the request is rejected
395 with an error message.
398 Attempts to watch wired kernel memory
399 may cause unrecoverable error in some systems such as i386.
400 Watchpoints on user addresses work best.
402 .It Ic hwatch Ar addr Ns Li , Ns Ar size
403 Set a hardware watchpoint for a region if supported by the
405 Execution stops when an attempt to modify the region occurs.
408 argument defaults to 4.
411 The hardware debug facilities do not have a concept of separate
412 address spaces like the watch command does.
415 for setting watchpoints on kernel address locations only, and avoid
416 its use on user mode address spaces.
418 .It Ic dhwatch Ar addr Ns Li , Ns Ar size
419 Delete specified hardware watchpoint.
421 .It Ic step Ns Op Li / Ns Cm p
422 .It Ic s Ns Op Li / Ns Cm p
425 times (the comma is a mandatory part of the syntax).
428 modifier is specified, print each instruction at each step.
429 Otherwise, only print the last instruction.
432 depending on machine type, it may not be possible to
433 single-step through some low-level code paths or user space code.
434 On machines with software-emulated single-stepping (e.g., pmax),
435 stepping through code executed by interrupt handlers will probably
438 .It Ic continue Ns Op Li / Ns Cm c
439 .It Ic c Ns Op Li / Ns Cm c
440 Continue execution until a breakpoint or watchpoint.
443 modifier is specified, count instructions while executing.
444 Some machines (e.g., pmax) also count loads and stores.
447 when counting, the debugger is really silently single-stepping.
448 This means that single-stepping on low-level code may cause strange
451 .It Ic until Ns Op Li / Ns Cm p
452 Stop at the next call or return instruction.
455 modifier is specified, print the call nesting depth and the
456 cumulative instruction count at each call or return.
458 only print when the matching return is hit.
460 .It Ic next Ns Op Li / Ns Cm p
461 .It Ic match Ns Op Li / Ns Cm p
462 Stop at the matching return instruction.
465 modifier is specified, print the call nesting depth and the
466 cumulative instruction count at each call or return.
467 Otherwise, only print when the matching return is hit.
470 .Ic trace Ns Op Li / Ns Cm u
475 .Ic t Ns Op Li / Ns Cm u
480 .Ic where Ns Op Li / Ns Cm u
485 .Ic bt Ns Op Li / Ns Cm u
492 option traces user space; if omitted,
496 The optional argument
498 is the number of frames to be traced.
501 is omitted, all frames are printed.
504 User space stack trace is valid
505 only if the machine dependent code supports it.
508 .Ic search Ns Op Li / Ns Cm bhl
516 This command might fail in interesting
517 ways if it does not find the searched-for value.
520 does not always recover from touching bad memory.
523 argument limits the search.
530 Prints the thread address for a thread kernel-mode stack of which contains the
532 If the thread is not found, search the thread stack cache and prints the
533 cached stack address.
534 Otherwise, prints nothing.
536 .It Ic show Cm all procs Ns Op Li / Ns Cm m
537 .It Ic ps Ns Op Li / Ns Cm m
538 Display all process information.
539 The process information may not be shown if it is not
540 supported in the machine, or the bottom of the stack of the
541 target process is not in the main memory at that time.
544 modifier will alter the display to show VM map
545 addresses for the process and not show other information.
548 .It Ic show Cm all ttys
549 Show all TTY's within the system.
552 but also includes the address of the TTY structure.
555 .It Ic show Cm allchains
556 Show the same information like "show lockchain" does, but
557 for every thread in the system.
560 .It Ic show Cm alllocks
561 Show all locks that are currently held.
562 This command is only available if
564 is included in the kernel.
567 .It Ic show Cm allpcpu
568 The same as "show pcpu", but for every CPU present in the system.
571 .It Ic show Cm allrman
572 Show information related with resource management, including
573 interrupt request lines, DMA request lines, I/O ports and I/O memory
578 Dump data about APIC IDT vector mappings.
581 .It Ic show Cm breaks
582 Show breakpoints set with the "break" command.
585 .It Ic show Cm buffer
586 Show buffer structure of
589 Such a structure is used within the
591 kernel for the I/O subsystem
593 For an exact interpretation of the output, please see the
598 .It Ic show Cm cbstat
599 Show brief information about the TTY subsystem.
603 Without argument, show the list of all created cdev's, consisting of devfs
604 node name and struct cdev address.
605 When address of cdev is supplied, show some internal devfs state of the cdev.
608 .It Ic show Cm conifhk
609 Lists hooks currently waiting for completion in
610 run_interrupt_driven_config_hooks().
613 .It Ic show Cm cpusets
614 Print numbered root and assigned CPU affinity sets.
620 .It Ic show Cm cyrixreg
621 Show registers specific to the Cyrix processor.
624 .It Ic show Cm domain Ar addr
625 Print protocol domain structure
631 header file for more details on the exact meaning of the structure fields.
634 .It Ic show Cm ffs Op Ar addr
635 Show brief information about ffs mount at the address
637 if argument is given.
638 Otherwise, provides the summary about each ffs mount.
641 .It Ic show Cm file Ar addr
642 Show information about the file structure
649 Show information about every file structure in the system.
652 .It Ic show Cm freepages
653 Show the number of physical pages in each of the free lists.
656 .It Ic show Cm geom Op Ar addr
659 argument is not given, displays the entire GEOM topology.
662 is given, displays details about the given GEOM object (class, geom,
663 provider or consumer).
668 The first column specifies the IDT vector.
669 The second one is the name of the interrupt/trap handler.
670 Those functions are machine dependent.
673 .It Ic show Cm inodedeps Op Ar addr
674 Show brief information about each inodedep structure.
677 is given, only inodedeps belonging to the fs located at the
678 supplied address are shown.
681 .It Ic show Cm inpcb Ar addr
682 Show information on IP Control Block
689 Dump information about interrupt handlers.
692 .It Ic show Cm intrcnt
693 Dump the interrupt statistics.
697 Show interrupt lines and their respective kernel threads.
706 shows, also list kernel internal details.
710 Show information from the local APIC registers for this CPU.
713 .It Ic show Cm lock Ar addr
715 The output format is as follows:
716 .Bl -tag -width "flags"
719 Possible types include
727 Flags passed to the lock initialization function.
728 For exact possibilities see manual pages of possible lock types.
730 Current state of a lock.
739 .It Ic show Cm lockchain Ar addr
740 Show all threads a particular thread at address
742 is waiting on based on non-sleepable and non-spin locks.
745 .It Ic show Cm lockedbufs
746 Show the same information as "show buf", but for every locked
751 .It Ic show Cm lockedvnods
752 List all locked vnodes in the system.
756 Prints all locks that are currently acquired.
757 This command is only available if
759 is included in the kernel.
762 .It Ic show Cm locktree
765 .It Ic show Cm malloc
768 memory allocator statistics.
769 The output format is as follows:
771 .Bl -tag -compact -offset indent -width "Requests"
773 Specifies a type of memory.
774 It is the same as a description string used while defining the
775 given memory type with
776 .Xr MALLOC_DECLARE 9 .
778 Number of memory allocations of the given type, for which
780 has not been called yet.
782 Total memory consumed by the given allocation type.
784 Number of memory allocation requests for the given
788 The same information can be gathered in userspace with
792 .It Ic show Cm map Ns Oo Li / Ns Cm f Oc Ar addr
797 modifier is specified the
798 complete map is printed.
801 .It Ic show Cm msgbuf
802 Print the system's message buffer.
803 It is the same output as in the
806 It is useful if you got a kernel panic, attached a serial cable
807 to the machine and want to get the boot messages from before the
811 Displays short info about all currently mounted file systems.
813 .It Ic show Cm mount Ar addr
814 Displays details about the given mount point.
817 .It Ic show Cm object Ns Oo Li / Ns Cm f Oc Ar addr
818 Prints the VM object at
822 option is specified the
823 complete object is printed.
827 Show statistics on VM pages.
831 Show statistics on VM page queues.
834 .It Ic show Cm pciregs
835 Print PCI bus registers.
836 The same information can be gathered in userspace by running
837 .Dq Nm pciconf Fl lv .
841 Print current processor state.
842 The output format is as follows:
844 .Bl -tag -compact -offset indent -width "spin locks held:"
846 Processor identifier.
848 Thread pointer, process identifier and the name of the process.
850 Control block pointer.
856 CPU identifier coming from APIC.
859 .It Ic spin locks held
860 Names of spin locks held.
864 .It Ic show Cm pgrpdump
865 Dump process groups present within the system.
868 .It Ic show Cm proc Op Ar addr
871 is specified, print information about the current process.
872 Otherwise, show information about the process at address
876 .It Ic show Cm procvm
877 Show process virtual memory layout.
880 .It Ic show Cm protosw Ar addr
881 Print protocol switch structure
887 .It Ic show Cm registers Ns Op Li / Ns Cm u
888 Display the register set.
891 modifier is specified, it displays user registers instead of
892 kernel registers or the currently saved one.
897 modifier depends on the machine.
898 If not supported, incorrect information will be displayed.
901 .It Ic show Cm rman Ar addr
902 Show resource manager object
906 Addresses of particular pointers can be gathered with "show allrman"
911 Show real time clock value.
912 Useful for long debugging sessions.
915 .It Ic show Cm sleepchain
916 Show all the threads a particular thread is waiting on based on
920 .It Ic show Cm sleepq
921 .It Ic show Cm sleepqueue
922 Both commands provide the same functionality.
924 .Vt struct sleepqueue
926 Sleepqueues are used within the
928 kernel to implement sleepable
929 synchronization primitives (thread holding a lock might sleep or
930 be context switched), which at the time of writing are:
938 .It Ic show Cm sockbuf Ar addr
939 .It Ic show Cm socket Ar addr
946 Output consists of all values present in structures mentioned.
947 For exact interpretation and more details, visit
952 .It Ic show Cm sysregs
953 Show system registers (e.g.,
956 Not present on some platforms.
959 .It Ic show Cm tcpcb Ar addr
960 Print TCP control block
964 For exact interpretation of output, visit
969 .It Ic show Cm thread Op Ar addr
972 is specified, show detailed information about current thread.
973 Otherwise, information about thread at
978 .It Ic show Cm threads
979 Show all threads within the system.
980 Output format is as follows:
982 .Bl -tag -compact -offset indent -width "Second column"
984 Thread identifier (TID)
986 Thread structure address
992 .It Ic show Cm tty Ar addr
993 Display the contents of a TTY structure in a readable form.
996 .It Ic show Cm turnstile Ar addr
1001 Turnstiles are structures used within the
1004 synchronization primitives which, while holding a specific type of lock, cannot
1005 sleep or context switch to another thread.
1006 Currently, those are:
1013 Show UMA allocator statistics.
1014 Output consists five columns:
1016 .Bl -tag -compact -offset indent -width "Requests"
1018 Name of the UMA zone.
1019 The same string that was passed to
1021 as a first argument.
1023 Size of a given memory object (slab).
1025 Number of slabs being currently used.
1027 Number of free slabs within the UMA zone.
1029 Number of allocations requests to the given zone.
1032 The very same information might be gathered in the userspace
1034 .Dq Nm vmstat Fl z .
1037 .It Ic show Cm unpcb Ar addr
1038 Shows UNIX domain socket private control block
1040 present at the address
1044 .It Ic show Cm vmochk
1045 Prints, whether the internal VM objects are in a map somewhere
1046 and none have zero ref counts.
1049 .It Ic show Cm vmopag
1050 This is supposed to show physical addresses consumed by a
1052 Currently, it is not possible to use this command when
1054 is compiled in the kernel.
1057 .It Ic show Cm vnode Op Ar addr
1062 For the exact interpretation of the output, look at the
1067 .It Ic show Cm vnodebufs Ar addr
1068 Shows clean/dirty buffer lists of the vnode located at
1072 .It Ic show Cm watches
1073 Displays all watchpoints.
1074 Shows watchpoints set with "watch" command.
1077 .It Ic show Cm witness
1078 Shows information about lock acquisition coming from the
1084 Toggles between remote GDB and DDB mode.
1085 In remote GDB mode, another machine is required that runs
1087 using the remote debug feature, with a connection to the serial
1088 console port on the target machine.
1089 Currently only available on the
1096 .It Ic kill Ar sig pid
1101 The signal is acted on upon returning from the debugger.
1102 This command can be used to kill a process causing resource contention
1103 in the case of a hung system.
1106 for a list of signals.
1107 Note that the arguments are reversed relative to
1110 .It Ic reboot Op Ar seconds
1111 .It Ic reset Op Ar seconds
1112 Hard reset the system.
1113 If the optional argument
1115 is given, the debugger will wait for this long, at most a week,
1119 Print a short summary of the available commands and command
1124 .It Ic capture reset
1125 .It Ic capture status
1127 supports a basic output capture facility, which can be used to retrieve the
1128 results of debugging commands from userpsace using
1131 enables output capture;
1135 will clear the capture buffer and disable capture.
1137 will report current buffer use, buffer size, and disposition of output
1140 Userspace processes may inspect and manage
1145 .Dv debug.ddb.capture.bufsize
1146 may be used to query or set the current capture buffer size.
1148 .Dv debug.ddb.capture.maxbufsize
1149 may be used to query the compile-time limit on the capture buffer size.
1151 .Dv debug.ddb.capture.bytes
1152 may be used to query the number of bytes of output currently in the capture
1155 .Dv debug.ddb.capture.data
1156 returns the contents of the buffer as a string to an appropriately privileged
1159 This facility is particularly useful in concert with the scripting and
1161 facilities, allowing scripted debugging output to be captured and
1162 committed to disk as part of a textdump for later analysis.
1163 The contents of the capture buffer may also be inspected in a kernel core dump
1171 Run, define, list, and delete scripts.
1174 section for more information on the scripting facility.
1177 .It Ic textdump status
1178 .It Ic textdump unset
1181 command may be used to force the next kernel core dump to be a textdump
1182 rather than a traditional memory dump or minidump.
1184 reports whether a textdump has been scheduled.
1186 cancels a request to perform a textdump as the next kernel core dump.
1187 More information may be found in
1191 The debugger accesses registers and variables as
1193 Register names are as in the
1194 .Dq Ic show Cm registers
1196 Some variables are suffixed with numbers, and may have some modifier
1197 following a colon immediately after the variable name.
1198 For example, register variables can have a
1200 modifier to indicate user register (e.g.,
1203 Built-in variables currently supported are:
1205 .Bl -tag -width ".Va tabstops" -compact
1207 Input and output radix.
1209 Addresses are printed as
1210 .Dq Ar symbol Ns Li + Ns Ar offset
1216 The width of the displayed line.
1218 The number of lines.
1219 It is used by the built-in pager.
1222 .It Va work Ns Ar xx
1225 can take values from 0 to 31.
1228 Most expression operators in C are supported except
1236 .Bl -tag -width ".No Identifiers"
1238 The name of a symbol is translated to the value of the symbol, which
1239 is the address of the corresponding object.
1243 can be used in the identifier.
1244 If supported by an object format dependent routine,
1246 .Oo Ar filename : Oc Ar func : lineno ,
1248 .Oo Ar filename : Oc Ns Ar variable ,
1250 .Oo Ar filename : Oc Ns Ar lineno
1251 can be accepted as a symbol.
1253 Radix is determined by the first two letters:
1259 decimal; otherwise, follow current radix.
1265 address of the start of the last line examined.
1270 this is only changed by
1276 last address explicitly specified.
1277 .It Li $ Ns Ar variable
1278 Translated to the value of the specified variable.
1279 It may be followed by a
1281 and modifiers as described above.
1282 .It Ar a Ns Li # Ns Ar b
1283 A binary operator which rounds up the left hand side to the next
1284 multiple of right hand side.
1287 It may be followed by a
1289 and modifiers as described above.
1293 supports a basic scripting facility to allow automating tasks or responses to
1295 Each script consists of a list of DDB commands to be executed sequentially,
1296 and is assigned a unique name.
1297 Certain script names have special meaning, and will be automatically run on
1300 events if scripts by those names have been defined.
1304 command may be used to define a script by name.
1305 Scripts consist of a series of
1307 commands separated with the
1311 .Bd -literal -offset indent
1312 script kdb.enter.panic=bt; show pcpu
1313 script lockinfo=show alllocks; show lockedvnods
1318 command lists currently defined scripts.
1322 command execute a script by name.
1324 .Bd -literal -offset indent
1330 command may be used to delete a script by name.
1332 .Bd -literal -offset indent
1333 unscript kdb.enter.panic
1336 These functions may also be performed from userspace using the
1340 Certain scripts are run automatically, if defined, for specific
1343 The follow scripts are run when various events occur:
1344 .Bl -tag -width kdb.enter.powerfail
1345 .It Dv kdb.enter.acpi
1346 The kernel debugger was entered as a result of an
1349 .It Dv kdb.enter.bootflags
1350 The kernel debugger was entered at boot as a result of the debugger boot
1352 .It Dv kdb.enter.break
1353 The kernel debugger was entered as a result of a serial or console break.
1354 .It Dv kdb.enter.cam
1355 The kernel debugger was entered as a result of a
1358 .It Dv kdb.enter.mac
1359 The kernel debugger was entered as a result of an assertion failure in the
1362 TrustedBSD MAC Framework.
1363 .It Dv kdb.enter.ndis
1364 The kernel debugger was entered as a result of an
1367 .It Dv kdb.enter.netgraph
1368 The kernel debugger was entered as a result of a
1371 .It Dv kdb.enter.panic
1374 .It Dv kdb.enter.powerfail
1375 The kernel debugger was entered as a result of a powerfail NMI on the sparc64
1377 .It Dv kdb.enter.powerpc
1378 The kernel debugger was entered as a result of an unimplemented interrupt
1379 type on the powerpc platform.
1380 .It Dv kdb.enter.sysctl
1381 The kernel debugger was entered as a result of the
1384 .It Dv kdb.enter.trapsig
1385 The kernel debugger was entered as a result of a trapsig event on the sparc64
1387 .It Dv kdb.enter.unionfs
1388 The kernel debugger was entered as a result of an assertion failure in the
1390 .It Dv kdb.enter.unknown
1391 The kernel debugger was entered, but no reason has been set.
1392 .It Dv kdb.enter.vfslock
1393 The kernel debugger was entered as a result of a VFS lock violation.
1394 .It Dv kdb.enter.watchdog
1395 The kernel debugger was entered as a result of a watchdog firing.
1396 .It Dv kdb.enter.witness
1397 The kernel debugger was entered as a result of a
1402 In the event that none of these scripts is found,
1404 will attempt to execute a default script:
1405 .Bl -tag -width kdb.enter.powerfail
1406 .It Dv kdb.enter.default
1407 The kernel debugger was entered, but a script exactly matching the reason for
1408 entering was not defined.
1409 This can be used as a catch-all to handle cases not specifically of interest;
1411 .Dv kdb.enter.witness
1412 might be defined to have special handling, and
1413 .Dv kdb.enter.default
1414 might be defined to simply panic and reboot.
1417 On machines with an ISA expansion bus, a simple NMI generation card can be
1418 constructed by connecting a push button between the A01 and B01 (CHCHK# and
1420 Momentarily shorting these two fingers together may cause the bridge chipset to
1421 generate an NMI, which causes the kernel to pass control to
1423 Some bridge chipsets do not generate a NMI on CHCHK#, so your mileage may vary.
1424 The NMI allows one to break into the debugger on a wedged machine to
1426 Other bus' bridge chipsets may be able to generate NMI using bus specific
1429 Header files mention in this manual page can be found below
1439 .Pa netinet/in_pcb.h
1461 debugger was developed for Mach, and ported to
1463 This manual page translated from
1466 .An Garrett Wollman .
1468 .An Robert N. M. Watson