---
name: "dtrace_kinst"
section: "4"
platform: "freebsd"
package: "base"
version: "16.0-CURRENT-20261027-61c70dc16a79"
release: "FreeBSD 16.0-CURRENT (2026-10-27)"
platforms: ["freebsd"]
url: "https://new.carta.tech/dtrace_kinst"
---

# dtrace\_kinst(4)

a DTrace provider for tracing arbitrary instructions in a given kernel function

## NAME

**dtrace\_kinst** – a DTrace provider for tracing arbitrary instructions in a given kernel function

## SYNOPSIS

kinst::\<function\>:\<instruction\>

## DESCRIPTION

The DTrace **kinst** provider allows the user to trace any instruction in a given kernel function. \<function\> corresponds to the function to be traced, and \<instruction\> is the offset to the specific instruction, and can be obtained from the function's disassembly using kgdb from the gdb package.

**kinst** creates probes on-demand, meaning it searches for and parses the function's instructions each time [dtrace(1)](/dtrace/1.md) is run, and not at module load time. This is in contrast to [dtrace\_fbt(4)](/dtrace_fbt/4.md)'s load-time parsing, since **kinst** can potentially create thousands of probes for just a single function, instead of up to two (entry and return) in the case of [dtrace\_fbt(4)](/dtrace_fbt/4.md). A result of this is that **dtrace** **-l** **-P** **kinst** will not match any probes.

## IMPLEMENTATION NOTES

The provider is currently implemented only for amd64.

## EXAMPLES

Find the offset corresponding to the third instruction in **vm\_fault**() and trace it, printing the contents of the RSI register:

```
# kgdb
(kgdb) disas /r vm_fault
Dump of assembler code for function vm_fault:
   0xffffffff80876df0 <+0>:     55      push   %rbp
   0xffffffff80876df1 <+1>:     48 89 e5        mov    %rsp,%rbp
   0xffffffff80876df4 <+4>:     41 57   push   %r15
# dtrace -n 'kinst::vm_fault:4 {printf("%#x", regs[R_RSI]);}'
  2  81500                       vm_fault:4 0x827c56000
  2  81500                       vm_fault:4 0x827878000
  2  81500                       vm_fault:4 0x1fab9bef0000
  2  81500                       vm_fault:4 0xe16cf749000
  0  81500                       vm_fault:4 0x13587c366000
  ...
```

Trace all instructions in **amd64\_syscall**():

```
# dtrace -n 'kinst::amd64_syscall:'
```

## SEE ALSO

[dtrace(1)](/dtrace/1.md), [dtrace\_fbt(4)](/dtrace_fbt/4.md)

## HISTORY

The **kinst** provider first appeared in FreeBSD 14.0.

## AUTHORS

This manual page was written by Christos Margiolis ⟨*christos@FreeBSD.org*⟩.