Copyright (c) 2007 Robert N. M. Watson
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$FreeBSD: head/share/man/man9/stack.9 173979 2007-11-27 11:02:41Z rwatson $

.Dd February 27, 2007 .Dt STACK 9 .Os .Sh NAME .Nm stack .Nd kernel thread stack tracing routines .Sh SYNOPSIS n sys/param.h> n sys/stack.h

p 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.

p 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 .

p A trace of the current kernel thread's call stack may be captured using .Fn stack_capture .

p .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.

p 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 .

p This manual page was written by .An Robert Watson .