freebsd-nq/share/man/man9/stack.9
2007-11-28 12:04:08 +00:00

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.Dd February 27, 2007
.Dt STACK 9
.Os
.Sh NAME
.Nm stack
.Nd kernel thread stack tracing routines
.Sh SYNOPSIS
.In sys/param.h>
.In sys/stack.h
.Pp
In kernel configuration files:
.Cd "options DDB"
.Ft struct stack *
.Fn stack_create "void"
.Ft void
.Fn stack_destroy "struct stack *st"
.Ft int
.Fn stack_put "struct stack *st" "vm_offset_t pc"
.Ft void
.Fn stack_copy "struct stack *src" "struct stack dst"
.Ft void
.Fn stack_zero "struct stack *st"
.Ft void
.Fn stack_sbuf_print "struct sbuf sb*" "struct stack *st"
.Ft void
.Fn stack_save "struct stack *st"
.Sh DESCRIPTION
The
.Nm
KPI allows querying of kernel stack trace information and the automated
generation of kernel stack trace strings for the purposes of debugging and
tracing.
.Nm
relies on the presence of
.Xr DDB 4 ,
and all use of these functions must be made conditional on
.Nm DDB
being compiled in the kernel.
.Pp
Each stack trace is described by a
.Vt "struct stack" .
Before a trace may be created or otherwise manipulated, storage for the trace
must be allocated with
.Fn stack_create ,
which may sleep.
Memory associated with a trace may be freed by calling
.Fn stack_destroy .
.Pp
A trace of the current kernel thread's call stack may be captured using
.Fn stack_save .
.Pp
.Fn stack_sbuf_print
may be used to construct a human-readable string, including conversion (where
possible) from a simple kernel instruction pointer to a named symbol and
offset.
The argument
.Ar sb
must be an initialized
.Dv struct sbuf
as described in
.Xr sbuf 9 .
This function may sleep if an auto-extending
.Dv struct sbuf
is used.
.Pp
The utility functions
.Nm stack_zero ,
.Nm stack_copy ,
and
.Nm stack_put
may be used to manipulate stack data structures directly.
.Sh SEE ALSO
.Xr DDB 4
.Sh AUTHORS
.An -nosplit
The
.Xr stack 9
function suite was created by
.An Antoine Brodin .
.Pp
This manual page was written by
.An Robert Watson .