1598 lines
37 KiB
Groff
1598 lines
37 KiB
Groff
.\"
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.\" Mach Operating System
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.\" Copyright (c) 1991,1990 Carnegie Mellon University
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.\" Copyright (c) 2007 Robert N. M. Watson
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.\" All Rights Reserved.
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.\"
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.\" Permission to use, copy, modify and distribute this software and its
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.\" documentation is hereby granted, provided that both the copyright
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.\" notice and this permission notice appear in all copies of the
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.\" software, derivative works or modified versions, and any portions
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.\" thereof, and that both notices appear in supporting documentation.
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.\"
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.\" CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
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.\" CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
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.\" ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
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.\"
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.\" Carnegie Mellon requests users of this software to return to
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.\"
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.\" Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
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.\" School of Computer Science
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.\" Carnegie Mellon University
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.\" Pittsburgh PA 15213-3890
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.\"
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.\" any improvements or extensions that they make and grant Carnegie Mellon
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.\" the rights to redistribute these changes.
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.\"
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.\" changed a \# to #, since groff choked on it.
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.\"
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.\" HISTORY
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.\" ddb.4,v
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.\" Revision 1.1 1993/07/15 18:41:02 brezak
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.\" Man page for DDB
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.\"
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.\" Revision 2.6 92/04/08 08:52:57 rpd
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.\" Changes from OSF.
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.\" [92/01/17 14:19:22 jsb]
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.\" Changes for OSF debugger modifications.
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.\" [91/12/12 tak]
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.\"
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.\" Revision 2.5 91/06/25 13:50:22 rpd
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.\" Added some watchpoint explanation.
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.\" [91/06/25 rpd]
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.\"
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.\" Revision 2.4 91/06/17 15:47:31 jsb
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.\" Added documentation for continue/c, match, search, and watchpoints.
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.\" I've not actually explained what a watchpoint is; maybe Rich can
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.\" do that (hint, hint).
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.\" [91/06/17 10:58:08 jsb]
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.\"
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.\" Revision 2.3 91/05/14 17:04:23 mrt
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.\" Correcting copyright
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.\"
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.\" Revision 2.2 91/02/14 14:10:06 mrt
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.\" Changed to new Mach copyright
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.\" [91/02/12 18:10:12 mrt]
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.\"
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.\" Revision 2.2 90/08/30 14:23:15 dbg
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.\" Created.
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.\" [90/08/30 dbg]
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.\"
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.\" $FreeBSD$
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.\"
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.Dd November 30, 2018
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.Dt DDB 4
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|
.Os
|
|
.Sh NAME
|
|
.Nm ddb
|
|
.Nd interactive kernel debugger
|
|
.Sh SYNOPSIS
|
|
In order to enable kernel debugging facilities include:
|
|
.Bd -ragged -offset indent
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|
.Cd options KDB
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|
.Cd options DDB
|
|
.Ed
|
|
.Pp
|
|
To prevent activation of the debugger on kernel
|
|
.Xr panic 9 :
|
|
.Bd -ragged -offset indent
|
|
.Cd options KDB_UNATTENDED
|
|
.Ed
|
|
.Pp
|
|
In order to print a stack trace of the current thread on the console
|
|
for a panic:
|
|
.Bd -ragged -offset indent
|
|
.Cd options KDB_TRACE
|
|
.Ed
|
|
.Pp
|
|
To print the numerical value of symbols in addition to the symbolic
|
|
representation, define:
|
|
.Bd -ragged -offset indent
|
|
.Cd options DDB_NUMSYM
|
|
.Ed
|
|
.Pp
|
|
To enable the
|
|
.Xr gdb 1
|
|
backend, so that remote debugging with
|
|
.Xr kgdb 1
|
|
is possible, include:
|
|
.Bd -ragged -offset indent
|
|
.Cd options GDB
|
|
.Ed
|
|
.Sh DESCRIPTION
|
|
The
|
|
.Nm
|
|
kernel debugger is an interactive debugger with a syntax inspired by
|
|
.Xr gdb 1 .
|
|
If linked into the running kernel,
|
|
it can be invoked locally with the
|
|
.Ql debug
|
|
.Xr keymap 5
|
|
action, usually mapped to Ctrl+Alt+Esc, or by setting the
|
|
.Va debug.kdb.enter
|
|
sysctl to 1.
|
|
The debugger is also invoked on kernel
|
|
.Xr panic 9
|
|
if the
|
|
.Va debug.debugger_on_panic
|
|
.Xr sysctl 8
|
|
MIB variable is set non-zero,
|
|
which is the default
|
|
unless the
|
|
.Dv KDB_UNATTENDED
|
|
option is specified.
|
|
.Pp
|
|
The current location is called
|
|
.Va dot .
|
|
The
|
|
.Va dot
|
|
is displayed with
|
|
a hexadecimal format at a prompt.
|
|
The commands
|
|
.Ic examine
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|
and
|
|
.Ic write
|
|
update
|
|
.Va dot
|
|
to the address of the last line
|
|
examined or the last location modified, and set
|
|
.Va next
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|
to the address of
|
|
the next location to be examined or changed.
|
|
Other commands do not change
|
|
.Va dot ,
|
|
and set
|
|
.Va next
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|
to be the same as
|
|
.Va dot .
|
|
.Pp
|
|
The general command syntax is:
|
|
.Ar command Ns Op Li / Ns Ar modifier
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|
.Oo Ar addr Oc Ns Op , Ns Ar count
|
|
.Pp
|
|
A blank line repeats the previous command from the address
|
|
.Va next
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|
with
|
|
count 1 and no modifiers.
|
|
Specifying
|
|
.Ar addr
|
|
sets
|
|
.Va dot
|
|
to the address.
|
|
Omitting
|
|
.Ar addr
|
|
uses
|
|
.Va dot .
|
|
A missing
|
|
.Ar count
|
|
is taken
|
|
to be 1 for printing commands or infinity for stack traces.
|
|
A
|
|
.Ar count
|
|
of -1 is equivalent to a missing
|
|
.Ar count .
|
|
Options that are supplied but not supported by the given
|
|
.Ar command
|
|
are usually ignored.
|
|
.Pp
|
|
The
|
|
.Nm
|
|
debugger has a pager feature (like the
|
|
.Xr more 1
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|
command)
|
|
for the output.
|
|
If an output line exceeds the number set in the
|
|
.Va lines
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|
variable, it displays
|
|
.Dq Li --More--
|
|
and waits for a response.
|
|
The valid responses for it are:
|
|
.Pp
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|
.Bl -tag -compact -width ".Li SPC"
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|
.It Li SPC
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|
one more page
|
|
.It Li RET
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|
one more line
|
|
.It Li q
|
|
abort the current command, and return to the command input mode
|
|
.El
|
|
.Pp
|
|
Finally,
|
|
.Nm
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|
provides a small (currently 10 items) command history, and offers
|
|
simple
|
|
.Nm emacs Ns -style
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|
command line editing capabilities.
|
|
In addition to
|
|
the
|
|
.Nm emacs
|
|
control keys, the usual
|
|
.Tn ANSI
|
|
arrow keys may be used to
|
|
browse through the history buffer, and move the cursor within the
|
|
current line.
|
|
.Sh COMMANDS
|
|
.Bl -tag -width indent -compact
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|
.It Xo
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|
.Ic examine Ns Op Li / Ns Cm AISabcdghilmorsuxz ...
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|
.Oo Ar addr Oc Ns Op , Ns Ar count
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|
.Xc
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|
.It Xo
|
|
.Ic x Ns Op Li / Ns Cm AISabcdghilmorsuxz ...
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|
.Oo Ar addr Oc Ns Op , Ns Ar count
|
|
.Xc
|
|
Display the addressed locations according to the formats in the modifier.
|
|
Multiple modifier formats display multiple locations.
|
|
If no format is specified, the last format specified for this command
|
|
is used.
|
|
.Pp
|
|
The format characters are:
|
|
.Bl -tag -compact -width indent
|
|
.It Cm b
|
|
look at by bytes (8 bits)
|
|
.It Cm h
|
|
look at by half words (16 bits)
|
|
.It Cm l
|
|
look at by long words (32 bits)
|
|
.It Cm g
|
|
look at by quad words (64 bits)
|
|
.It Cm a
|
|
print the location being displayed
|
|
.It Cm A
|
|
print the location with a line number if possible
|
|
.It Cm x
|
|
display in unsigned hex
|
|
.It Cm z
|
|
display in signed hex
|
|
.It Cm o
|
|
display in unsigned octal
|
|
.It Cm d
|
|
display in signed decimal
|
|
.It Cm u
|
|
display in unsigned decimal
|
|
.It Cm r
|
|
display in current radix, signed
|
|
.It Cm c
|
|
display low 8 bits as a character.
|
|
Non-printing characters are displayed as an octal escape code (e.g.,
|
|
.Ql \e000 ) .
|
|
.It Cm s
|
|
display the null-terminated string at the location.
|
|
Non-printing characters are displayed as octal escapes.
|
|
.It Cm m
|
|
display in unsigned hex with character dump at the end of each line.
|
|
The location is also displayed in hex at the beginning of each line.
|
|
.It Cm i
|
|
display as a disassembled instruction
|
|
.It Cm I
|
|
display as an disassembled instruction with possible alternate formats depending on the
|
|
machine.
|
|
On i386, this selects the alternate format for the instruction decoding
|
|
(16 bits in a 32-bit code segment and vice versa).
|
|
.It Cm S
|
|
display a symbol name for the pointer stored at the address
|
|
.El
|
|
.Pp
|
|
.It Ic xf
|
|
Examine forward:
|
|
execute an
|
|
.Ic examine
|
|
command with the last specified parameters to it
|
|
except that the next address displayed by it is used as the start address.
|
|
.Pp
|
|
.It Ic xb
|
|
Examine backward:
|
|
execute an
|
|
.Ic examine
|
|
command with the last specified parameters to it
|
|
except that the last start address subtracted by the size displayed by it
|
|
is used as the start address.
|
|
.Pp
|
|
.It Ic print Ns Op Li / Ns Cm acdoruxz
|
|
.It Ic p Ns Op Li / Ns Cm acdoruxz
|
|
Print
|
|
.Ar addr Ns s
|
|
according to the modifier character (as described above for
|
|
.Cm examine ) .
|
|
Valid formats are:
|
|
.Cm a , x , z , o , d , u , r ,
|
|
and
|
|
.Cm c .
|
|
If no modifier is specified, the last one specified to it is used.
|
|
The argument
|
|
.Ar addr
|
|
can be a string, in which case it is printed as it is.
|
|
For example:
|
|
.Bd -literal -offset indent
|
|
print/x "eax = " $eax "\enecx = " $ecx "\en"
|
|
.Ed
|
|
.Pp
|
|
will print like:
|
|
.Bd -literal -offset indent
|
|
eax = xxxxxx
|
|
ecx = yyyyyy
|
|
.Ed
|
|
.Pp
|
|
.It Xo
|
|
.Ic write Ns Op Li / Ns Cm bhl
|
|
.Ar addr expr1 Op Ar expr2 ...
|
|
.Xc
|
|
.It Xo
|
|
.Ic w Ns Op Li / Ns Cm bhl
|
|
.Ar addr expr1 Op Ar expr2 ...
|
|
.Xc
|
|
Write the expressions specified after
|
|
.Ar addr
|
|
on the command line at succeeding locations starting with
|
|
.Ar addr .
|
|
The write unit size can be specified in the modifier with a letter
|
|
.Cm b
|
|
(byte),
|
|
.Cm h
|
|
(half word) or
|
|
.Cm l
|
|
(long word) respectively.
|
|
If omitted,
|
|
long word is assumed.
|
|
.Pp
|
|
.Sy Warning :
|
|
since there is no delimiter between expressions, strange
|
|
things may happen.
|
|
It is best to enclose each expression in parentheses.
|
|
.Pp
|
|
.It Ic set Li $ Ns Ar variable Oo Li = Oc Ar expr
|
|
Set the named variable or register with the value of
|
|
.Ar expr .
|
|
Valid variable names are described below.
|
|
.Pp
|
|
.It Ic break Ns Oo Li / Ns Cm u Oc Oo Ar addr Oc Ns Op , Ns Ar count
|
|
.It Ic b Ns Oo Li / Ns Cm u Oc Oo Ar addr Oc Ns Op , Ns Ar count
|
|
Set a break point at
|
|
.Ar addr .
|
|
If
|
|
.Ar count
|
|
is supplied, the
|
|
.Ic continue
|
|
command will not stop at this break point on the first
|
|
.Ar count
|
|
\- 1 times that it is hit.
|
|
If the break point is set, a break point number is
|
|
printed with
|
|
.Ql # .
|
|
This number can be used in deleting the break point
|
|
or adding conditions to it.
|
|
.Pp
|
|
If the
|
|
.Cm u
|
|
modifier is specified, this command sets a break point in user
|
|
address space.
|
|
Without the
|
|
.Cm u
|
|
option, the address is considered to be in the kernel
|
|
space, and a wrong space address is rejected with an error message.
|
|
This modifier can be used only if it is supported by machine dependent
|
|
routines.
|
|
.Pp
|
|
.Sy Warning :
|
|
If a user text is shadowed by a normal user space debugger,
|
|
user space break points may not work correctly.
|
|
Setting a break
|
|
point at the low-level code paths may also cause strange behavior.
|
|
.Pp
|
|
.It Ic delete Op Ar addr
|
|
.It Ic d Op Ar addr
|
|
.It Ic delete Li # Ns Ar number
|
|
.It Ic d Li # Ns Ar number
|
|
Delete the specified break point.
|
|
The break point can be specified by a
|
|
break point number with
|
|
.Ql # ,
|
|
or by using the same
|
|
.Ar addr
|
|
specified in the original
|
|
.Ic break
|
|
command, or by omitting
|
|
.Ar addr
|
|
to get the default address of
|
|
.Va dot .
|
|
.Pp
|
|
.It Ic watch Oo Ar addr Oc Ns Op , Ns Ar size
|
|
Set a watchpoint for a region.
|
|
Execution stops when an attempt to modify the region occurs.
|
|
The
|
|
.Ar size
|
|
argument defaults to 4.
|
|
If you specify a wrong space address, the request is rejected
|
|
with an error message.
|
|
.Pp
|
|
.Sy Warning :
|
|
Attempts to watch wired kernel memory
|
|
may cause unrecoverable error in some systems such as i386.
|
|
Watchpoints on user addresses work best.
|
|
.Pp
|
|
.It Ic hwatch Oo Ar addr Oc Ns Op , Ns Ar size
|
|
Set a hardware watchpoint for a region if supported by the
|
|
architecture.
|
|
Execution stops when an attempt to modify the region occurs.
|
|
The
|
|
.Ar size
|
|
argument defaults to 4.
|
|
.Pp
|
|
.Sy Warning :
|
|
The hardware debug facilities do not have a concept of separate
|
|
address spaces like the watch command does.
|
|
Use
|
|
.Ic hwatch
|
|
for setting watchpoints on kernel address locations only, and avoid
|
|
its use on user mode address spaces.
|
|
.Pp
|
|
.It Ic dhwatch Oo Ar addr Oc Ns Op , Ns Ar size
|
|
Delete specified hardware watchpoint.
|
|
.Pp
|
|
.It Ic step Ns Oo Li / Ns Cm p Oc Ns Op , Ns Ar count
|
|
.It Ic s Ns Oo Li / Ns Cm p Oc Ns Op , Ns Ar count
|
|
Single step
|
|
.Ar count
|
|
times.
|
|
If the
|
|
.Cm p
|
|
modifier is specified, print each instruction at each step.
|
|
Otherwise, only print the last instruction.
|
|
.Pp
|
|
.Sy Warning :
|
|
depending on machine type, it may not be possible to
|
|
single-step through some low-level code paths or user space code.
|
|
On machines with software-emulated single-stepping (e.g., pmax),
|
|
stepping through code executed by interrupt handlers will probably
|
|
do the wrong thing.
|
|
.Pp
|
|
.It Ic continue Ns Op Li / Ns Cm c
|
|
.It Ic c Ns Op Li / Ns Cm c
|
|
Continue execution until a breakpoint or watchpoint.
|
|
If the
|
|
.Cm c
|
|
modifier is specified, count instructions while executing.
|
|
Some machines (e.g., pmax) also count loads and stores.
|
|
.Pp
|
|
.Sy Warning :
|
|
when counting, the debugger is really silently single-stepping.
|
|
This means that single-stepping on low-level code may cause strange
|
|
behavior.
|
|
.Pp
|
|
.It Ic until Ns Op Li / Ns Cm p
|
|
Stop at the next call or return instruction.
|
|
If the
|
|
.Cm p
|
|
modifier is specified, print the call nesting depth and the
|
|
cumulative instruction count at each call or return.
|
|
Otherwise,
|
|
only print when the matching return is hit.
|
|
.Pp
|
|
.It Ic next Ns Op Li / Ns Cm p
|
|
.It Ic match Ns Op Li / Ns Cm p
|
|
Stop at the matching return instruction.
|
|
If the
|
|
.Cm p
|
|
modifier is specified, print the call nesting depth and the
|
|
cumulative instruction count at each call or return.
|
|
Otherwise, only print when the matching return is hit.
|
|
.Pp
|
|
.It Xo
|
|
.Ic trace Ns Op Li / Ns Cm u
|
|
.Op Ar pid | tid Ns
|
|
.Op , Ns Ar count
|
|
.Xc
|
|
.It Xo
|
|
.Ic t Ns Op Li / Ns Cm u
|
|
.Op Ar pid | tid Ns
|
|
.Op , Ns Ar count
|
|
.Xc
|
|
.It Xo
|
|
.Ic where Ns Op Li / Ns Cm u
|
|
.Op Ar pid | tid Ns
|
|
.Op , Ns Ar count
|
|
.Xc
|
|
.It Xo
|
|
.Ic bt Ns Op Li / Ns Cm u
|
|
.Op Ar pid | tid Ns
|
|
.Op , Ns Ar count
|
|
.Xc
|
|
Stack trace.
|
|
The
|
|
.Cm u
|
|
option traces user space; if omitted,
|
|
.Ic trace
|
|
only traces
|
|
kernel space.
|
|
The optional argument
|
|
.Ar count
|
|
is the number of frames to be traced.
|
|
If
|
|
.Ar count
|
|
is omitted, all frames are printed.
|
|
.Pp
|
|
.Sy Warning :
|
|
User space stack trace is valid
|
|
only if the machine dependent code supports it.
|
|
.Pp
|
|
.It Xo
|
|
.Ic search Ns Op Li / Ns Cm bhl
|
|
.Ar addr
|
|
.Ar value
|
|
.Op Ar mask Ns
|
|
.Op , Ns Ar count
|
|
.Xc
|
|
Search memory for
|
|
.Ar value .
|
|
The optional
|
|
.Ar count
|
|
argument limits the search.
|
|
.\"
|
|
.Pp
|
|
.It Xo
|
|
.Ic findstack
|
|
.Ar addr
|
|
.Xc
|
|
Prints the thread address for a thread kernel-mode stack of which contains the
|
|
specified address.
|
|
If the thread is not found, search the thread stack cache and prints the
|
|
cached stack address.
|
|
Otherwise, prints nothing.
|
|
.Pp
|
|
.It Ic show Cm all procs Ns Op Li / Ns Cm a
|
|
.It Ic ps Ns Op Li / Ns Cm a
|
|
Display all process information.
|
|
The process information may not be shown if it is not
|
|
supported in the machine, or the bottom of the stack of the
|
|
target process is not in the main memory at that time.
|
|
The
|
|
.Cm a
|
|
modifier will print command line arguments for each process.
|
|
.\"
|
|
.Pp
|
|
.It Ic show Cm all trace
|
|
.It Ic alltrace
|
|
Show a stack trace for every thread in the system.
|
|
.Pp
|
|
.It Ic show Cm all ttys
|
|
Show all TTY's within the system.
|
|
Output is similar to
|
|
.Xr pstat 8 ,
|
|
but also includes the address of the TTY structure.
|
|
.\"
|
|
.Pp
|
|
.It Ic show Cm all vnets
|
|
Show the same output as "show vnet" does, but lists all
|
|
virtualized network stacks within the system.
|
|
.\"
|
|
.Pp
|
|
.It Ic show Cm allchains
|
|
Show the same information like "show lockchain" does, but
|
|
for every thread in the system.
|
|
.\"
|
|
.Pp
|
|
.It Ic show Cm alllocks
|
|
Show all locks that are currently held.
|
|
This command is only available if
|
|
.Xr witness 4
|
|
is included in the kernel.
|
|
.\"
|
|
.Pp
|
|
.It Ic show Cm allpcpu
|
|
The same as "show pcpu", but for every CPU present in the system.
|
|
.\"
|
|
.Pp
|
|
.It Ic show Cm allrman
|
|
Show information related with resource management, including
|
|
interrupt request lines, DMA request lines, I/O ports, I/O memory
|
|
addresses, and Resource IDs.
|
|
.\"
|
|
.Pp
|
|
.It Ic show Cm apic
|
|
Dump data about APIC IDT vector mappings.
|
|
.\"
|
|
.Pp
|
|
.It Ic show Cm breaks
|
|
Show breakpoints set with the "break" command.
|
|
.\"
|
|
.Pp
|
|
.It Ic show Cm bio Ar addr
|
|
Show information about the bio structure
|
|
.Vt struct bio
|
|
present at
|
|
.Ar addr .
|
|
See the
|
|
.Pa sys/bio.h
|
|
header file and
|
|
.Xr g_bio 9
|
|
for more details on the exact meaning of the structure fields.
|
|
.\"
|
|
.Pp
|
|
.It Ic show Cm buffer Ar addr
|
|
Show information about the buf structure
|
|
.Vt struct buf
|
|
present at
|
|
.Ar addr .
|
|
See the
|
|
.Pa sys/buf.h
|
|
header file for more details on the exact meaning of the structure fields.
|
|
.\"
|
|
.Pp
|
|
.It Ic show Cm callout Ar addr
|
|
Show information about the callout structure
|
|
.Vt struct callout
|
|
present at
|
|
.Ar addr .
|
|
.\"
|
|
.Pp
|
|
.It Ic show Cm cbstat
|
|
Show brief information about the TTY subsystem.
|
|
.\"
|
|
.Pp
|
|
.It Ic show Cm cdev
|
|
Without argument, show the list of all created cdev's, consisting of devfs
|
|
node name and struct cdev address.
|
|
When address of cdev is supplied, show some internal devfs state of the cdev.
|
|
.\"
|
|
.Pp
|
|
.It Ic show Cm conifhk
|
|
Lists hooks currently waiting for completion in
|
|
run_interrupt_driven_config_hooks().
|
|
.\"
|
|
.Pp
|
|
.It Ic show Cm cpusets
|
|
Print numbered root and assigned CPU affinity sets.
|
|
See
|
|
.Xr cpuset 2
|
|
for more details.
|
|
.\"
|
|
.Pp
|
|
.It Ic show Cm cyrixreg
|
|
Show registers specific to the Cyrix processor.
|
|
.\"
|
|
.Pp
|
|
.It Ic show Cm devmap
|
|
Prints the contents of the static device mapping table.
|
|
Currently only available on the
|
|
ARM
|
|
architecture.
|
|
.\"
|
|
.Pp
|
|
.It Ic show Cm domain Ar addr
|
|
Print protocol domain structure
|
|
.Vt struct domain
|
|
at address
|
|
.Ar addr .
|
|
See the
|
|
.Pa sys/domain.h
|
|
header file for more details on the exact meaning of the structure fields.
|
|
.\"
|
|
.Pp
|
|
.It Ic show Cm ffs Op Ar addr
|
|
Show brief information about ffs mount at the address
|
|
.Ar addr ,
|
|
if argument is given.
|
|
Otherwise, provides the summary about each ffs mount.
|
|
.\"
|
|
.Pp
|
|
.It Ic show Cm file Ar addr
|
|
Show information about the file structure
|
|
.Vt struct file
|
|
present at address
|
|
.Ar addr .
|
|
.\"
|
|
.Pp
|
|
.It Ic show Cm files
|
|
Show information about every file structure in the system.
|
|
.\"
|
|
.Pp
|
|
.It Ic show Cm freepages
|
|
Show the number of physical pages in each of the free lists.
|
|
.\"
|
|
.Pp
|
|
.It Ic show Cm geom Op Ar addr
|
|
If the
|
|
.Ar addr
|
|
argument is not given, displays the entire GEOM topology.
|
|
If
|
|
.Ar addr
|
|
is given, displays details about the given GEOM object (class, geom,
|
|
provider or consumer).
|
|
.\"
|
|
.Pp
|
|
.It Ic show Cm idt
|
|
Show IDT layout.
|
|
The first column specifies the IDT vector.
|
|
The second one is the name of the interrupt/trap handler.
|
|
Those functions are machine dependent.
|
|
.\"
|
|
.Pp
|
|
.It Ic show Cm igi_list Ar addr
|
|
Show information about the IGMP structure
|
|
.Vt struct igmp_ifsoftc
|
|
present at
|
|
.Ar addr .
|
|
.\"
|
|
.Pp
|
|
.It Ic show Cm inodedeps Op Ar addr
|
|
Show brief information about each inodedep structure.
|
|
If
|
|
.Ar addr
|
|
is given, only inodedeps belonging to the fs located at the
|
|
supplied address are shown.
|
|
.\"
|
|
.Pp
|
|
.It Ic show Cm inpcb Ar addr
|
|
Show information on IP Control Block
|
|
.Vt struct in_pcb
|
|
present at
|
|
.Ar addr .
|
|
.\"
|
|
.Pp
|
|
.It Ic show Cm intr
|
|
Dump information about interrupt handlers.
|
|
.\"
|
|
.Pp
|
|
.It Ic show Cm intrcnt
|
|
Dump the interrupt statistics.
|
|
.\"
|
|
.Pp
|
|
.It Ic show Cm irqs
|
|
Show interrupt lines and their respective kernel threads.
|
|
.\"
|
|
.Pp
|
|
.It Ic show Cm jails
|
|
Show the list of
|
|
.Xr jail 8
|
|
instances.
|
|
In addition to what
|
|
.Xr jls 8
|
|
shows, also list kernel internal details.
|
|
.\"
|
|
.Pp
|
|
.It Ic show Cm lapic
|
|
Show information from the local APIC registers for this CPU.
|
|
.\"
|
|
.Pp
|
|
.It Ic show Cm lock Ar addr
|
|
Show lock structure.
|
|
The output format is as follows:
|
|
.Bl -tag -width "flags"
|
|
.It Ic class:
|
|
Class of the lock.
|
|
Possible types include
|
|
.Xr mutex 9 ,
|
|
.Xr rmlock 9 ,
|
|
.Xr rwlock 9 ,
|
|
.Xr sx 9 .
|
|
.It Ic name:
|
|
Name of the lock.
|
|
.It Ic flags:
|
|
Flags passed to the lock initialization function.
|
|
.Em flags
|
|
values are lock class specific.
|
|
.It Ic state:
|
|
Current state of a lock.
|
|
.Em state
|
|
values are lock class specific.
|
|
.It Ic owner:
|
|
Lock owner.
|
|
.El
|
|
.\"
|
|
.Pp
|
|
.It Ic show Cm lockchain Ar addr
|
|
Show all threads a particular thread at address
|
|
.Ar addr
|
|
is waiting on based on non-spin locks.
|
|
.\"
|
|
.Pp
|
|
.It Ic show Cm lockedbufs
|
|
Show the same information as "show buf", but for every locked
|
|
.Vt struct buf
|
|
object.
|
|
.\"
|
|
.Pp
|
|
.It Ic show Cm lockedvnods
|
|
List all locked vnodes in the system.
|
|
.\"
|
|
.Pp
|
|
.It Ic show Cm locks
|
|
Prints all locks that are currently acquired.
|
|
This command is only available if
|
|
.Xr witness 4
|
|
is included in the kernel.
|
|
.\"
|
|
.Pp
|
|
.It Ic show Cm locktree
|
|
.\"
|
|
.Pp
|
|
.It Ic show Cm malloc
|
|
Prints
|
|
.Xr malloc 9
|
|
memory allocator statistics.
|
|
The output format is as follows:
|
|
.Pp
|
|
.Bl -tag -compact -offset indent -width "Requests"
|
|
.It Ic Type
|
|
Specifies a type of memory.
|
|
It is the same as a description string used while defining the
|
|
given memory type with
|
|
.Xr MALLOC_DECLARE 9 .
|
|
.It Ic InUse
|
|
Number of memory allocations of the given type, for which
|
|
.Xr free 9
|
|
has not been called yet.
|
|
.It Ic MemUse
|
|
Total memory consumed by the given allocation type.
|
|
.It Ic Requests
|
|
Number of memory allocation requests for the given
|
|
memory type.
|
|
.El
|
|
.Pp
|
|
The same information can be gathered in userspace with
|
|
.Dq Nm vmstat Fl m .
|
|
.\"
|
|
.Pp
|
|
.It Ic show Cm map Ns Oo Li / Ns Cm f Oc Ar addr
|
|
Prints the VM map at
|
|
.Ar addr .
|
|
If the
|
|
.Cm f
|
|
modifier is specified the
|
|
complete map is printed.
|
|
.\"
|
|
.Pp
|
|
.It Ic show Cm msgbuf
|
|
Print the system's message buffer.
|
|
It is the same output as in the
|
|
.Dq Nm dmesg
|
|
case.
|
|
It is useful if you got a kernel panic, attached a serial cable
|
|
to the machine and want to get the boot messages from before the
|
|
system hang.
|
|
.\"
|
|
.It Ic show Cm mount
|
|
Displays short info about all currently mounted file systems.
|
|
.Pp
|
|
.It Ic show Cm mount Ar addr
|
|
Displays details about the given mount point.
|
|
.\"
|
|
.Pp
|
|
.It Ic show Cm object Ns Oo Li / Ns Cm f Oc Ar addr
|
|
Prints the VM object at
|
|
.Ar addr .
|
|
If the
|
|
.Cm f
|
|
option is specified the
|
|
complete object is printed.
|
|
.\"
|
|
.Pp
|
|
.It Ic show Cm panic
|
|
Print the panic message if set.
|
|
.\"
|
|
.Pp
|
|
.It Ic show Cm page
|
|
Show statistics on VM pages.
|
|
.\"
|
|
.Pp
|
|
.It Ic show Cm pageq
|
|
Show statistics on VM page queues.
|
|
.\"
|
|
.Pp
|
|
.It Ic show Cm pciregs
|
|
Print PCI bus registers.
|
|
The same information can be gathered in userspace by running
|
|
.Dq Nm pciconf Fl lv .
|
|
.\"
|
|
.Pp
|
|
.It Ic show Cm pcpu
|
|
Print current processor state.
|
|
The output format is as follows:
|
|
.Pp
|
|
.Bl -tag -compact -offset indent -width "spin locks held:"
|
|
.It Ic cpuid
|
|
Processor identifier.
|
|
.It Ic curthread
|
|
Thread pointer, process identifier and the name of the process.
|
|
.It Ic curpcb
|
|
Control block pointer.
|
|
.It Ic fpcurthread
|
|
FPU thread pointer.
|
|
.It Ic idlethread
|
|
Idle thread pointer.
|
|
.It Ic APIC ID
|
|
CPU identifier coming from APIC.
|
|
.It Ic currentldt
|
|
LDT pointer.
|
|
.It Ic spin locks held
|
|
Names of spin locks held.
|
|
.El
|
|
.\"
|
|
.Pp
|
|
.It Ic show Cm pgrpdump
|
|
Dump process groups present within the system.
|
|
.\"
|
|
.Pp
|
|
.It Ic show Cm proc Op Ar addr
|
|
If no
|
|
.Op Ar addr
|
|
is specified, print information about the current process.
|
|
Otherwise, show information about the process at address
|
|
.Ar addr .
|
|
.\"
|
|
.Pp
|
|
.It Ic show Cm procvm
|
|
Show process virtual memory layout.
|
|
.\"
|
|
.Pp
|
|
.It Ic show Cm protosw Ar addr
|
|
Print protocol switch structure
|
|
.Vt struct protosw
|
|
at address
|
|
.Ar addr .
|
|
.\"
|
|
.Pp
|
|
.It Ic show Cm registers Ns Op Li / Ns Cm u
|
|
Display the register set.
|
|
If the
|
|
.Cm u
|
|
modifier is specified, it displays user registers instead of
|
|
kernel registers or the currently saved one.
|
|
.Pp
|
|
.Sy Warning :
|
|
The support of the
|
|
.Cm u
|
|
modifier depends on the machine.
|
|
If not supported, incorrect information will be displayed.
|
|
.\"
|
|
.Pp
|
|
.It Ic show Cm rman Ar addr
|
|
Show resource manager object
|
|
.Vt struct rman
|
|
at address
|
|
.Ar addr .
|
|
Addresses of particular pointers can be gathered with "show allrman"
|
|
command.
|
|
.\"
|
|
.Pp
|
|
.It Ic show Cm rtc
|
|
Show real time clock value.
|
|
Useful for long debugging sessions.
|
|
.\"
|
|
.Pp
|
|
.It Ic show Cm sleepchain
|
|
Deprecated.
|
|
Now an alias for
|
|
.Ic show Cm lockchain .
|
|
.\"
|
|
.Pp
|
|
.It Ic show Cm sleepq
|
|
.It Ic show Cm sleepqueue
|
|
Both commands provide the same functionality.
|
|
They show sleepqueue
|
|
.Vt struct sleepqueue
|
|
structure.
|
|
Sleepqueues are used within the
|
|
.Fx
|
|
kernel to implement sleepable
|
|
synchronization primitives (thread holding a lock might sleep or
|
|
be context switched), which at the time of writing are:
|
|
.Xr condvar 9 ,
|
|
.Xr sx 9
|
|
and standard
|
|
.Xr msleep 9
|
|
interface.
|
|
.\"
|
|
.Pp
|
|
.It Ic show Cm sockbuf Ar addr
|
|
.It Ic show Cm socket Ar addr
|
|
Those commands print
|
|
.Vt struct sockbuf
|
|
and
|
|
.Vt struct socket
|
|
objects placed at
|
|
.Ar addr .
|
|
Output consists of all values present in structures mentioned.
|
|
For exact interpretation and more details, visit
|
|
.Pa sys/socket.h
|
|
header file.
|
|
.\"
|
|
.Pp
|
|
.It Ic show Cm sysregs
|
|
Show system registers (e.g.,
|
|
.Li cr0-4
|
|
on i386.)
|
|
Not present on some platforms.
|
|
.\"
|
|
.Pp
|
|
.It Ic show Cm tcpcb Ar addr
|
|
Print TCP control block
|
|
.Vt struct tcpcb
|
|
lying at address
|
|
.Ar addr .
|
|
For exact interpretation of output, visit
|
|
.Pa netinet/tcp.h
|
|
header file.
|
|
.\"
|
|
.Pp
|
|
.It Ic show Cm thread Op Ar addr | tid
|
|
If no
|
|
.Ar addr
|
|
or
|
|
.Ar tid
|
|
is specified, show detailed information about current thread.
|
|
Otherwise, print information about the thread with ID
|
|
.Ar tid
|
|
or kernel address
|
|
.Ar addr .
|
|
(If the argument is a decimal number, it is assumed to be a tid.)
|
|
.\"
|
|
.Pp
|
|
.It Ic show Cm threads
|
|
Show all threads within the system.
|
|
Output format is as follows:
|
|
.Pp
|
|
.Bl -tag -compact -offset indent -width "Second column"
|
|
.It Ic First column
|
|
Thread identifier (TID)
|
|
.It Ic Second column
|
|
Thread structure address
|
|
.It Ic Third column
|
|
Backtrace.
|
|
.El
|
|
.\"
|
|
.Pp
|
|
.It Ic show Cm tty Ar addr
|
|
Display the contents of a TTY structure in a readable form.
|
|
.\"
|
|
.Pp
|
|
.It Ic show Cm turnstile Ar addr
|
|
Show turnstile
|
|
.Vt struct turnstile
|
|
structure at address
|
|
.Ar addr .
|
|
Turnstiles are structures used within the
|
|
.Fx
|
|
kernel to implement
|
|
synchronization primitives which, while holding a specific type of lock, cannot
|
|
sleep or context switch to another thread.
|
|
Currently, those are:
|
|
.Xr mutex 9 ,
|
|
.Xr rwlock 9 ,
|
|
.Xr rmlock 9 .
|
|
.\"
|
|
.Pp
|
|
.It Ic show Cm uma
|
|
Show UMA allocator statistics.
|
|
Output consists five columns:
|
|
.Pp
|
|
.Bl -tag -compact -offset indent -width "Requests"
|
|
.It Cm "Zone"
|
|
Name of the UMA zone.
|
|
The same string that was passed to
|
|
.Xr uma_zcreate 9
|
|
as a first argument.
|
|
.It Cm "Size"
|
|
Size of a given memory object (slab).
|
|
.It Cm "Used"
|
|
Number of slabs being currently used.
|
|
.It Cm "Free"
|
|
Number of free slabs within the UMA zone.
|
|
.It Cm "Requests"
|
|
Number of allocations requests to the given zone.
|
|
.El
|
|
.Pp
|
|
The very same information might be gathered in the userspace
|
|
with the help of
|
|
.Dq Nm vmstat Fl z .
|
|
.\"
|
|
.Pp
|
|
.It Ic show Cm unpcb Ar addr
|
|
Shows UNIX domain socket private control block
|
|
.Vt struct unpcb
|
|
present at the address
|
|
.Ar addr .
|
|
.\"
|
|
.Pp
|
|
.It Ic show Cm vmochk
|
|
Prints, whether the internal VM objects are in a map somewhere
|
|
and none have zero ref counts.
|
|
.\"
|
|
.Pp
|
|
.It Ic show Cm vmopag
|
|
This is supposed to show physical addresses consumed by a
|
|
VM object.
|
|
Currently, it is not possible to use this command when
|
|
.Xr witness 4
|
|
is compiled in the kernel.
|
|
.\"
|
|
.Pp
|
|
.It Ic show Cm vnet Ar addr
|
|
Prints virtualized network stack
|
|
.Vt struct vnet
|
|
structure present at the address
|
|
.Ar addr .
|
|
.\"
|
|
.Pp
|
|
.It Ic show Cm vnode Op Ar addr
|
|
Prints vnode
|
|
.Vt struct vnode
|
|
structure lying at
|
|
.Op Ar addr .
|
|
For the exact interpretation of the output, look at the
|
|
.Pa sys/vnode.h
|
|
header file.
|
|
.\"
|
|
.Pp
|
|
.It Ic show Cm vnodebufs Ar addr
|
|
Shows clean/dirty buffer lists of the vnode located at
|
|
.Ar addr .
|
|
.\"
|
|
.Pp
|
|
.It Ic show Cm vpath Ar addr
|
|
Walk the namecache to lookup the pathname of the vnode located at
|
|
.Ar addr .
|
|
.\"
|
|
.Pp
|
|
.It Ic show Cm watches
|
|
Displays all watchpoints.
|
|
Shows watchpoints set with "watch" command.
|
|
.\"
|
|
.Pp
|
|
.It Ic show Cm witness
|
|
Shows information about lock acquisition coming from the
|
|
.Xr witness 4
|
|
subsystem.
|
|
.\"
|
|
.Pp
|
|
.It Ic gdb
|
|
Toggles between remote GDB and DDB mode.
|
|
In remote GDB mode, another machine is required that runs
|
|
.Xr gdb 1
|
|
using the remote debug feature, with a connection to the serial
|
|
console port on the target machine.
|
|
Currently only available on the
|
|
i386
|
|
architecture.
|
|
.Pp
|
|
.It Ic halt
|
|
Halt the system.
|
|
.Pp
|
|
.It Ic kill Ar sig pid
|
|
Send signal
|
|
.Ar sig
|
|
to process
|
|
.Ar pid .
|
|
The signal is acted on upon returning from the debugger.
|
|
This command can be used to kill a process causing resource contention
|
|
in the case of a hung system.
|
|
See
|
|
.Xr signal 3
|
|
for a list of signals.
|
|
Note that the arguments are reversed relative to
|
|
.Xr kill 2 .
|
|
.Pp
|
|
.It Ic reboot Op Ar seconds
|
|
.It Ic reset Op Ar seconds
|
|
Hard reset the system.
|
|
If the optional argument
|
|
.Ar seconds
|
|
is given, the debugger will wait for this long, at most a week,
|
|
before rebooting.
|
|
.Pp
|
|
.It Ic help
|
|
Print a short summary of the available commands and command
|
|
abbreviations.
|
|
.Pp
|
|
.It Ic capture on
|
|
.It Ic capture off
|
|
.It Ic capture reset
|
|
.It Ic capture status
|
|
.Nm
|
|
supports a basic output capture facility, which can be used to retrieve the
|
|
results of debugging commands from userspace using
|
|
.Xr sysctl 3 .
|
|
.Ic capture on
|
|
enables output capture;
|
|
.Ic capture off
|
|
disables capture.
|
|
.Ic capture reset
|
|
will clear the capture buffer and disable capture.
|
|
.Ic capture status
|
|
will report current buffer use, buffer size, and disposition of output
|
|
capture.
|
|
.Pp
|
|
Userspace processes may inspect and manage
|
|
.Nm
|
|
capture state using
|
|
.Xr sysctl 8 :
|
|
.Pp
|
|
.Va debug.ddb.capture.bufsize
|
|
may be used to query or set the current capture buffer size.
|
|
.Pp
|
|
.Va debug.ddb.capture.maxbufsize
|
|
may be used to query the compile-time limit on the capture buffer size.
|
|
.Pp
|
|
.Va debug.ddb.capture.bytes
|
|
may be used to query the number of bytes of output currently in the capture
|
|
buffer.
|
|
.Pp
|
|
.Va debug.ddb.capture.data
|
|
returns the contents of the buffer as a string to an appropriately privileged
|
|
process.
|
|
.Pp
|
|
This facility is particularly useful in concert with the scripting and
|
|
.Xr textdump 4
|
|
facilities, allowing scripted debugging output to be captured and
|
|
committed to disk as part of a textdump for later analysis.
|
|
The contents of the capture buffer may also be inspected in a kernel core dump
|
|
using
|
|
.Xr kgdb 1 .
|
|
.Pp
|
|
.It Ic run
|
|
.It Ic script
|
|
.It Ic scripts
|
|
.It Ic unscript
|
|
Run, define, list, and delete scripts.
|
|
See the
|
|
.Sx SCRIPTING
|
|
section for more information on the scripting facility.
|
|
.Pp
|
|
.It Ic textdump dump
|
|
.It Ic textdump set
|
|
.It Ic textdump status
|
|
.It Ic textdump unset
|
|
Use the
|
|
.Ic textdump dump
|
|
command to immediately perform a textdump.
|
|
More information may be found in
|
|
.Xr textdump 4 .
|
|
The
|
|
.Ic textdump set
|
|
command may be used to force the next kernel core dump to be a textdump
|
|
rather than a traditional memory dump or minidump.
|
|
.Ic textdump status
|
|
reports whether a textdump has been scheduled.
|
|
.Ic textdump unset
|
|
cancels a request to perform a textdump as the next kernel core dump.
|
|
.Pp
|
|
.It Ic thread Ar addr | tid
|
|
Switch the debugger to the thread with ID
|
|
.Ar tid ,
|
|
if the argument is a decimal number, or address
|
|
.Ar addr ,
|
|
otherwise.
|
|
.El
|
|
.Sh VARIABLES
|
|
The debugger accesses registers and variables as
|
|
.Li $ Ns Ar name .
|
|
Register names are as in the
|
|
.Dq Ic show Cm registers
|
|
command.
|
|
Some variables are suffixed with numbers, and may have some modifier
|
|
following a colon immediately after the variable name.
|
|
For example, register variables can have a
|
|
.Cm u
|
|
modifier to indicate user register (e.g.,
|
|
.Dq Li $eax:u ) .
|
|
.Pp
|
|
Built-in variables currently supported are:
|
|
.Pp
|
|
.Bl -tag -width ".Va tabstops" -compact
|
|
.It Va radix
|
|
Input and output radix.
|
|
.It Va maxoff
|
|
Addresses are printed as
|
|
.Dq Ar symbol Ns Li + Ns Ar offset
|
|
unless
|
|
.Ar offset
|
|
is greater than
|
|
.Va maxoff .
|
|
.It Va maxwidth
|
|
The width of the displayed line.
|
|
.It Va lines
|
|
The number of lines.
|
|
It is used by the built-in pager.
|
|
Setting it to 0 disables paging.
|
|
.It Va tabstops
|
|
Tab stop width.
|
|
.It Va work Ns Ar xx
|
|
Work variable;
|
|
.Ar xx
|
|
can take values from 0 to 31.
|
|
.El
|
|
.Sh EXPRESSIONS
|
|
Most expression operators in C are supported except
|
|
.Ql ~ ,
|
|
.Ql ^ ,
|
|
and unary
|
|
.Ql & .
|
|
Special rules in
|
|
.Nm
|
|
are:
|
|
.Bl -tag -width ".No Identifiers"
|
|
.It Identifiers
|
|
The name of a symbol is translated to the value of the symbol, which
|
|
is the address of the corresponding object.
|
|
.Ql \&.
|
|
and
|
|
.Ql \&:
|
|
can be used in the identifier.
|
|
If supported by an object format dependent routine,
|
|
.Sm off
|
|
.Oo Ar filename : Oc Ar func : lineno ,
|
|
.Sm on
|
|
.Oo Ar filename : Oc Ns Ar variable ,
|
|
and
|
|
.Oo Ar filename : Oc Ns Ar lineno
|
|
can be accepted as a symbol.
|
|
.It Numbers
|
|
Radix is determined by the first two letters:
|
|
.Ql 0x :
|
|
hex,
|
|
.Ql 0o :
|
|
octal,
|
|
.Ql 0t :
|
|
decimal; otherwise, follow current radix.
|
|
.It Li \&.
|
|
.Va dot
|
|
.It Li +
|
|
.Va next
|
|
.It Li ..
|
|
address of the start of the last line examined.
|
|
Unlike
|
|
.Va dot
|
|
or
|
|
.Va next ,
|
|
this is only changed by
|
|
.Ic examine
|
|
or
|
|
.Ic write
|
|
command.
|
|
.It Li '
|
|
last address explicitly specified.
|
|
.It Li $ Ns Ar variable
|
|
Translated to the value of the specified variable.
|
|
It may be followed by a
|
|
.Ql \&:
|
|
and modifiers as described above.
|
|
.It Ar a Ns Li # Ns Ar b
|
|
A binary operator which rounds up the left hand side to the next
|
|
multiple of right hand side.
|
|
.It Li * Ns Ar expr
|
|
Indirection.
|
|
It may be followed by a
|
|
.Ql \&:
|
|
and modifiers as described above.
|
|
.El
|
|
.Sh SCRIPTING
|
|
.Nm
|
|
supports a basic scripting facility to allow automating tasks or responses to
|
|
specific events.
|
|
Each script consists of a list of DDB commands to be executed sequentially,
|
|
and is assigned a unique name.
|
|
Certain script names have special meaning, and will be automatically run on
|
|
various
|
|
.Nm
|
|
events if scripts by those names have been defined.
|
|
.Pp
|
|
The
|
|
.Ic script
|
|
command may be used to define a script by name.
|
|
Scripts consist of a series of
|
|
.Nm
|
|
commands separated with the
|
|
.Ql \&;
|
|
character.
|
|
For example:
|
|
.Bd -literal -offset indent
|
|
script kdb.enter.panic=bt; show pcpu
|
|
script lockinfo=show alllocks; show lockedvnods
|
|
.Ed
|
|
.Pp
|
|
The
|
|
.Ic scripts
|
|
command lists currently defined scripts.
|
|
.Pp
|
|
The
|
|
.Ic run
|
|
command execute a script by name.
|
|
For example:
|
|
.Bd -literal -offset indent
|
|
run lockinfo
|
|
.Ed
|
|
.Pp
|
|
The
|
|
.Ic unscript
|
|
command may be used to delete a script by name.
|
|
For example:
|
|
.Bd -literal -offset indent
|
|
unscript kdb.enter.panic
|
|
.Ed
|
|
.Pp
|
|
These functions may also be performed from userspace using the
|
|
.Xr ddb 8
|
|
command.
|
|
.Pp
|
|
Certain scripts are run automatically, if defined, for specific
|
|
.Nm
|
|
events.
|
|
The follow scripts are run when various events occur:
|
|
.Bl -tag -width kdb.enter.powerfail
|
|
.It Va kdb.enter.acpi
|
|
The kernel debugger was entered as a result of an
|
|
.Xr acpi 4
|
|
event.
|
|
.It Va kdb.enter.bootflags
|
|
The kernel debugger was entered at boot as a result of the debugger boot
|
|
flag being set.
|
|
.It Va kdb.enter.break
|
|
The kernel debugger was entered as a result of a serial or console break.
|
|
.It Va kdb.enter.cam
|
|
The kernel debugger was entered as a result of a
|
|
.Xr CAM 4
|
|
event.
|
|
.It Va kdb.enter.mac
|
|
The kernel debugger was entered as a result of an assertion failure in the
|
|
.Xr mac_test 4
|
|
module of the
|
|
TrustedBSD MAC Framework.
|
|
.It Va kdb.enter.ndis
|
|
The kernel debugger was entered as a result of an
|
|
.Xr ndis 4
|
|
breakpoint event.
|
|
.It Va kdb.enter.netgraph
|
|
The kernel debugger was entered as a result of a
|
|
.Xr netgraph 4
|
|
event.
|
|
.It Va kdb.enter.panic
|
|
.Xr panic 9
|
|
was called.
|
|
.It Va kdb.enter.powerfail
|
|
The kernel debugger was entered as a result of a powerfail NMI on the sparc64
|
|
platform.
|
|
.It Va kdb.enter.powerpc
|
|
The kernel debugger was entered as a result of an unimplemented interrupt
|
|
type on the powerpc platform.
|
|
.It Va kdb.enter.sysctl
|
|
The kernel debugger was entered as a result of the
|
|
.Va debug.kdb.enter
|
|
sysctl being set.
|
|
.It Va kdb.enter.trapsig
|
|
The kernel debugger was entered as a result of a trapsig event on the sparc64
|
|
platform.
|
|
.It Va kdb.enter.unionfs
|
|
The kernel debugger was entered as a result of an assertion failure in the
|
|
union file system.
|
|
.It Va kdb.enter.unknown
|
|
The kernel debugger was entered, but no reason has been set.
|
|
.It Va kdb.enter.vfslock
|
|
The kernel debugger was entered as a result of a VFS lock violation.
|
|
.It Va kdb.enter.watchdog
|
|
The kernel debugger was entered as a result of a watchdog firing.
|
|
.It Va kdb.enter.witness
|
|
The kernel debugger was entered as a result of a
|
|
.Xr witness 4
|
|
violation.
|
|
.El
|
|
.Pp
|
|
In the event that none of these scripts is found,
|
|
.Nm
|
|
will attempt to execute a default script:
|
|
.Bl -tag -width kdb.enter.powerfail
|
|
.It Va kdb.enter.default
|
|
The kernel debugger was entered, but a script exactly matching the reason for
|
|
entering was not defined.
|
|
This can be used as a catch-all to handle cases not specifically of interest;
|
|
for example,
|
|
.Va kdb.enter.witness
|
|
might be defined to have special handling, and
|
|
.Va kdb.enter.default
|
|
might be defined to simply panic and reboot.
|
|
.El
|
|
.Sh HINTS
|
|
On machines with an ISA expansion bus, a simple NMI generation card can be
|
|
constructed by connecting a push button between the A01 and B01 (CHCHK# and
|
|
GND) card fingers.
|
|
Momentarily shorting these two fingers together may cause the bridge chipset to
|
|
generate an NMI, which causes the kernel to pass control to
|
|
.Nm .
|
|
Some bridge chipsets do not generate a NMI on CHCHK#, so your mileage may vary.
|
|
The NMI allows one to break into the debugger on a wedged machine to
|
|
diagnose problems.
|
|
Other bus' bridge chipsets may be able to generate NMI using bus specific
|
|
methods.
|
|
There are many PCI and PCIe add-in cards which can generate NMI for
|
|
debugging.
|
|
Modern server systems typically use IPMI to generate signals to enter the
|
|
debugger.
|
|
The
|
|
.Va devel/ipmitool
|
|
port can be used to send the
|
|
.Cd chassis power diag
|
|
command which delivers an NMI to the processor.
|
|
Embedded systems often use JTAG for debugging, but rarely use it in
|
|
combination with
|
|
.Nm .
|
|
.Pp
|
|
For serial consoles, you can enter the debugger by sending a BREAK
|
|
condition on the serial line if
|
|
.Cd options BREAK_TO_DEBUGGER
|
|
is specified in the kernel.
|
|
Most terminal emulation programs can send a break sequence with a
|
|
special key sequence or via a menu item.
|
|
However, in some setups, sending the break can be difficult to arrange
|
|
or happens spuriously, so if the kernel contains
|
|
.Cd options ALT_BREAK_TO_DEBUGGER
|
|
then the sequence of CR TILDE CTRL-B enters the debugger;
|
|
CR TILDE CTRL-P causes a panic instead of entering the
|
|
debugger; and
|
|
CR TILDE CTRL-R causes an immediate reboot.
|
|
In all the above sequences, CR is a Carriage Return and is usually
|
|
sent by hitting the Enter or Return key.
|
|
TILDE is the ASCII tilde character (~).
|
|
CTRL-x is Control x created by hitting the control key and then x
|
|
and then releasing both.
|
|
.Pp
|
|
The break to enter the debugger behavior may be enabled at run-time
|
|
by setting the
|
|
.Xr sysctl 8
|
|
.Va debug.kdb.break_to_debugger
|
|
to 1.
|
|
The alternate sequence to enter the debugger behavior may be enabled
|
|
at run-time by setting the
|
|
.Xr sysctl 8
|
|
.Va debug.kdb.alt_break_to_debugger
|
|
to 1.
|
|
The debugger may be entered by setting the
|
|
.Xr sysctl 8
|
|
.Va debug.kdb.enter
|
|
to 1.
|
|
.Sh FILES
|
|
Header files mentioned in this manual page can be found below
|
|
.Pa /usr/include
|
|
directory.
|
|
.Pp
|
|
.Bl -dash -compact
|
|
.It
|
|
.Pa sys/buf.h
|
|
.It
|
|
.Pa sys/domain.h
|
|
.It
|
|
.Pa netinet/in_pcb.h
|
|
.It
|
|
.Pa sys/socket.h
|
|
.It
|
|
.Pa sys/vnode.h
|
|
.El
|
|
.Sh SEE ALSO
|
|
.Xr gdb 1 ,
|
|
.Xr kgdb 1 ,
|
|
.Xr acpi 4 ,
|
|
.Xr CAM 4 ,
|
|
.Xr mac_test 4 ,
|
|
.Xr ndis 4 ,
|
|
.Xr netgraph 4 ,
|
|
.Xr textdump 4 ,
|
|
.Xr witness 4 ,
|
|
.Xr ddb 8 ,
|
|
.Xr sysctl 8 ,
|
|
.Xr panic 9
|
|
.Sh HISTORY
|
|
The
|
|
.Nm
|
|
debugger was developed for Mach, and ported to
|
|
.Bx 386 0.1 .
|
|
This manual page translated from
|
|
.Xr man 7
|
|
macros by
|
|
.An Garrett Wollman .
|
|
.Pp
|
|
.An Robert N. M. Watson
|
|
added support for
|
|
.Nm
|
|
output capture,
|
|
.Xr textdump 4
|
|
and scripting in
|
|
.Fx 7.1 .
|