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Red Hat Enterprise Linux 5

SystemTap Tapset Reference

For SystemTap in Red Hat Enterprise Linux 5

Edition 1

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Red Hat Enterprise Linux Documentation

William Cohen

Engineering Services and Operations Performance Tools

Don Domingo

Engineering Services and Operations Content Services

Legal Notice

This documentation is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License version 2 as published by the Free Software Foundation.
This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
For more details see the file COPYING in the source distribution of Linux.
Abstract
The Tapset Reference Guide describes the most common tapset definitions users can apply to SystemTap scripts. All included tapsets documented in this guide are current as of the latest upstream version of SystemTap.
Preface
1. Document Conventions
1.1. Typographic Conventions
1.2. Pull-quote Conventions
1.3. Notes and Warnings
2. Getting Help and Giving Feedback
2.1. Do You Need Help?
2.2. We Need Feedback!
1. Introduction
1.1. Documentation Goals
2. Tapset Development Guidelines
2.1. Writing Good Tapsets
2.2. Elements of a Tapset
2.2.1. Tapset Files
2.2.2. Namespace
2.2.3. Comments and Documentation
3. Context Functions
print_regs — Print a register dump.
execname — Returns the execname of a target process (or group of processes).
pid — Returns the ID of a target process.
tid — Returns the thread ID of a target process.
ppid — Returns the process ID of a target process's parent process.
pgrp — Returns the process group ID of the current process.
sid — Returns the session ID of the current process.
pexecname — Returns the execname of a target process's parent process.
gid — Returns the group ID of a target process.
egid — Returns the effective gid of a target process.
uid — Returns the user ID of a target process.
euid — Return the effective uid of a target process.
cpu — Returns the current cpu number.
pp — Return the probe point associated with the currently running probe handler,
registers_valid — Determines validity of register and u_register in current context.
user_mode — Determines if probe point occurs in user-mode.
is_return — Determines if probe point is a return probe.
target — Return the process ID of the target process.
stack_size — Return the size of the kernel stack.
stack_used — Returns the amount of kernel stack used.
stack_unused — Returns the amount of kernel stack currently available.
uaddr — User space address of current running task. EXPERIMENTAL.
print_stack — Print out stack from string.
probefunc — Return the probe point's function name, if known.
probemod — Return the probe point's module name, if known.
modname — Return the kernel module name loaded at the address.
symname — Return the symbol associated with the given address.
symdata — Return the symbol and module offset for the address.
usymname — Return the symbol of an address in the current task. EXPERIMENTAL!
usymdata — Return the symbol and module offset of an address. EXPERIMENTAL!
print_ustack — Print out stack for the current task from string. EXPERIMENTAL!
print_backtrace — Print stack back trace
backtrace — Hex backtrace of current stack
caller — Return name and address of calling function
caller_addr — Return caller address
print_ubacktrace — Print stack back trace for current task. EXPERIMENTAL!
ubacktrace — Hex backtrace of current task stack. EXPERIMENTAL!
4. Timestamp Functions
get_cycles — Processor cycle count.
5. Memory Tapset
vm_fault_contains — Test return value for page fault reason
vm.pagefault — Records that a page fault occurred.
vm.pagefault.return — Indicates what type of fault occurred.
addr_to_node — Returns which node a given address belongs to within a NUMA system.
vm.write_shared — Attempts at writing to a shared page.
vm.write_shared_copy — Page copy for shared page write.
vm.mmap — Fires when an mmap is requested.
vm.munmap — Fires when an munmap is requested.
vm.brk — Fires when a brk is requested (i.e. the heap will be resized).
vm.oom_kill — Fires when a thread is selected for termination by the OOM killer.
6. IO Scheduler Tapset
ioscheduler.elv_next_request — Fires when a request is retrieved from the request queue
ioscheduler.elv_next_request.return — Fires when a request retrieval issues a return signal
ioscheduler.elv_add_request — A request was added to the request queue
ioscheduler.elv_completed_request — Fires when a request is completed
7. SCSI Tapset
scsi.ioentry — Prepares a SCSI mid-layer request
scsi.iodispatching — SCSI mid-layer dispatched low-level SCSI command
scsi.iodone — SCSI command completed by low level driver and enqueued into the done queue.
scsi.iocompleted — SCSI mid-layer running the completion processing for block device I/O requests
8. Networking Tapset
netdev.receive — Data recieved from network device.
netdev.transmit — Network device transmitting buffer
tcp.sendmsg — Sending a tcp message
tcp.sendmsg.return — Sending TCP message is done
tcp.recvmsg — Receiving TCP message
tcp.recvmsg.return — Receiving TCP message complete
tcp.disconnect — TCP socket disconnection
tcp.disconnect.return — TCP socket disconnection complete
tcp.setsockopt — Call to setsockopt
tcp.setsockopt.return — Return from setsockopt
tcp.receive — Called when a TCP packet is received
udp.sendmsg — Fires whenever a process sends a UDP message
udp.sendmsg.return — Fires whenever an attempt to send a UDP message is completed
udp.recvmsg — Fires whenever a UDP message is received
udp.recvmsg.return — Fires whenever an attempt to receive a UDP message received is completed
udp.disconnect — Fires when a process requests for a UDP disconnection
udp.disconnect.return — UDP has been disconnected successfully
ip_ntop — returns a string representation from an integer IP number
9. Socket Tapset
socket.send — Message sent on a socket.
socket.receive — Message received on a socket.
socket.sendmsg — Message is currently being sent on a socket.
socket.sendmsg.return — Return from socket.sendmsg.
socket.recvmsg — Message being received on socket
socket.recvmsg.return — Return from Message being received on socket
socket.aio_write — Message send via sock_aio_write
socket.aio_write.return — Conclusion of message send via sock_aio_write
socket.aio_read — Receiving message via sock_aio_read
socket.aio_read.return — Conclusion of message received via sock_aio_read
socket.writev — Message sent via socket_writev
socket.writev.return — Conclusion of message sent via socket_writev
socket.readv — Receiving a message via sock_readv
socket.readv.return — Conclusion of receiving a message via sock_readv
socket.create — Creation of a socket
socket.create.return — Return from Creation of a socket
socket.close — Close a socket
socket.close.return — Return from closing a socket
sock_prot_num2str — Given a protocol number, return a string representation.
sock_prot_str2num — Given a protocol name (string), return the corresponding protocol number.
sock_fam_num2str — Given a protocol family number, return a string representation.
sock_fam_str2num — Given a protocol family name (string), return the corresponding
sock_state_num2str — Given a socket state number, return a string representation.
sock_state_str2num — Given a socket state string, return the corresponding state number.
10. Kernel Process Tapset
kprocess.create — Fires whenever a new process is successfully created
kprocess.start — Starting new process
kprocess.exec — Attempt to exec to a new program
kprocess.exec_complete — Return from exec to a new program
kprocess.exit — Exit from process
kprocess.release — Process released
11. Signal Tapset
signal.send — Signal being sent to a process
signal.send.return — Signal being sent to a process completed
signal.checkperm — Check being performed on a sent signal
signal.checkperm.return — Check performed on a sent signal completed
signal.wakeup — Sleeping process being wakened for signal
signal.check_ignored — Checking to see signal is ignored
signal.check_ignored.return — Check to see signal is ignored completed
signal.force_segv — Forcing send of SIGSEGV
signal.force_segv.return — Forcing send of SIGSEGV complete
signal.syskill — Sending kill signal to a process
signal.syskill.return — Sending kill signal completed
signal.sys_tkill — Sending a kill signal to a thread
signal.systkill.return — Sending kill signal to a thread completed
signal.sys_tgkill — Sending kill signal to a thread group
signal.sys_tgkill.return — Sending kill signal to a thread group completed
signal.send_sig_queue — Queuing a signal to a process
signal.send_sig_queue.return — Queuing a signal to a process completed
signal.pending — Examining pending signal
signal.pending.return — Examination of pending signal completed
signal.handle — Signal handler being invoked
signal.handle.return — Signal handler invocation completed
signal.do_action — Examining or changing a signal action
signal.do_action.return — Examining or changing a signal action completed
signal.procmask — Examining or changing blocked signals
signal.flush — Flusing all pending signals for a task
A. Revision History

Preface

1. Document Conventions

This manual uses several conventions to highlight certain words and phrases and draw attention to specific pieces of information.
In PDF and paper editions, this manual uses typefaces drawn from the Liberation Fonts set. The Liberation Fonts set is also used in HTML editions if the set is installed on your system. If not, alternative but equivalent typefaces are displayed. Note: Red Hat Enterprise Linux 5 and later includes the Liberation Fonts set by default.

1.1. Typographic Conventions

Four typographic conventions are used to call attention to specific words and phrases. These conventions, and the circumstances they apply to, are as follows.
Mono-spaced Bold
Used to highlight system input, including shell commands, file names and paths. Also used to highlight keycaps and key combinations. For example:
To see the contents of the file my_next_bestselling_novel in your current working directory, enter the cat my_next_bestselling_novel command at the shell prompt and press Enter to execute the command.
The above includes a file name, a shell command and a keycap, all presented in mono-spaced bold and all distinguishable thanks to context.
Key combinations can be distinguished from keycaps by the hyphen connecting each part of a key combination. For example:
Press Enter to execute the command.
Press Ctrl+Alt+F2 to switch to the first virtual terminal. Press Ctrl+Alt+F1 to return to your X-Windows session.
The first paragraph highlights the particular keycap to press. The second highlights two key combinations (each a set of three keycaps with each set pressed simultaneously).
If source code is discussed, class names, methods, functions, variable names and returned values mentioned within a paragraph will be presented as above, in mono-spaced bold. For example:
File-related classes include filesystem for file systems, file for files, and dir for directories. Each class has its own associated set of permissions.
Proportional Bold
This denotes words or phrases encountered on a system, including application names; dialog box text; labeled buttons; check-box and radio button labels; menu titles and sub-menu titles. For example:
Choose System → Preferences → Mouse from the main menu bar to launch Mouse Preferences. In the Buttons tab, click the Left-handed mouse check box and click Close to switch the primary mouse button from the left to the right (making the mouse suitable for use in the left hand).
To insert a special character into a gedit file, choose Applications → Accessories → Character Map from the main menu bar. Next, choose Search → Find… from the Character Map menu bar, type the name of the character in the Search field and click Next. The character you sought will be highlighted in the Character Table. Double-click this highlighted character to place it in the Text to copy field and then click the Copy button. Now switch back to your document and choose Edit → Paste from the gedit menu bar.
The above text includes application names; system-wide menu names and items; application-specific menu names; and buttons and text found within a GUI interface, all presented in proportional bold and all distinguishable by context.
Mono-spaced Bold Italic or Proportional Bold Italic
Whether mono-spaced bold or proportional bold, the addition of italics indicates replaceable or variable text. Italics denotes text you do not input literally or displayed text that changes depending on circumstance. For example:
To connect to a remote machine using ssh, type ssh username@domain.name at a shell prompt. If the remote machine is example.com and your username on that machine is john, type ssh john@example.com.
The mount -o remount file-system command remounts the named file system. For example, to remount the /home file system, the command is mount -o remount /home.
To see the version of a currently installed package, use the rpm -q package command. It will return a result as follows: package-version-release.
Note the words in bold italics above — username, domain.name, file-system, package, version and release. Each word is a placeholder, either for text you enter when issuing a command or for text displayed by the system.
Aside from standard usage for presenting the title of a work, italics denotes the first use of a new and important term. For example:
Publican is a DocBook publishing system.

1.2. Pull-quote Conventions

Terminal output and source code listings are set off visually from the surrounding text.
Output sent to a terminal is set in mono-spaced roman and presented thus: 
books        Desktop   documentation  drafts  mss    photos   stuff  svn
books_tests  Desktop1  downloads      images  notes  scripts  svgs
Source-code listings are also set in mono-spaced roman but add syntax highlighting as follows: 
package org.jboss.book.jca.ex1;

import javax.naming.InitialContext;

public class ExClient
{
   public static void main(String args[]) 
       throws Exception
   {
      InitialContext iniCtx = new InitialContext();
      Object         ref    = iniCtx.lookup("EchoBean");
      EchoHome       home   = (EchoHome) ref;
      Echo           echo   = home.create();

      System.out.println("Created Echo");

      System.out.println("Echo.echo('Hello') = " + echo.echo("Hello"));
   }
}

1.3. Notes and Warnings

Finally, we use three visual styles to draw attention to information that might otherwise be overlooked.

Note

Notes are tips, shortcuts or alternative approaches to the task at hand. Ignoring a note should have no negative consequences, but you might miss out on a trick that makes your life easier.

Important

Important boxes detail things that are easily missed: configuration changes that only apply to the current session, or services that need restarting before an update will apply. Ignoring a box labeled 'Important' will not cause data loss but may cause irritation and frustration.

Warning

Warnings should not be ignored. Ignoring warnings will most likely cause data loss.

2. Getting Help and Giving Feedback

2.1. Do You Need Help?

If you experience difficulty with a procedure described in this documentation, visit the Red Hat Customer Portal at http://access.redhat.com. Through the customer portal, you can:
  • search or browse through a knowledgebase of technical support articles about Red Hat products.
  • submit a support case to Red Hat Global Support Services (GSS).
  • access other product documentation.
Red Hat also hosts a large number of electronic mailing lists for discussion of Red Hat software and technology. You can find a list of publicly available mailing lists at https://www.redhat.com/mailman/listinfo. Click on the name of any mailing list to subscribe to that list or to access the list archives.

2.2. We Need Feedback!

If you find a typographical error in this manual, or if you have thought of a way to make this manual better, we would love to hear from you! Please submit a report in Bugzilla: http://bugzilla.redhat.com/ against the product Red_Hat_Enterprise_Linux.
When submitting a bug report, be sure to mention the manual's identifier: Tapset_Reference_Guide
If you have a suggestion for improving the documentation, try to be as specific as possible when describing it. If you have found an error, please include the section number and some of the surrounding text so we can find it easily.

Chapter 1. Introduction

1.1. Documentation Goals
SystemTap provides free software (GPL) infrastructure to simplify the gathering of information about the running Linux system. This assists diagnosis of a performance or functional problem. SystemTap eliminates the need for the developer to go through the tedious and disruptive instrument, recompile, install, and reboot sequence that may be otherwise required to collect data.
SystemTap provides a simple command line interface and scripting language for writing instrumentation for a live, running kernel. This instrumentation uses probe points and functions provided in the tapset library.
Simply put, tapsets are scripts that encapsulate knowledge about a kernel subsystem into pre-written probes and functions that can be used by other scripts. Tapsets are analogous to libraries for C programs. They hide the underlying details of a kernel area while exposing the key information needed to manage and monitor that aspect of the kernel. They are typically developed by kernel subject-matter experts.
A tapset exposes the high-level data and state transitions of a subsystem. For the most part, good tapset developers assume that SystemTap users know little to nothing about the kernel subsystem's low-level details. As such, tapset developers write tapsets that help ordinary SystemTap users write meaningful and useful SystemTap scripts.

1.1. Documentation Goals

This guide aims to document SystemTap's most useful and common tapset entries; it also contains guidelines on proper tapset development and documentation. The tapset definitions contained in this guide are extracted automatically from properly-formatted comments in the code of each tapset file. As such, any revisions to the definitions in this guide should be applied directly to their respective tapset file.

Chapter 2. Tapset Development Guidelines

2.1. Writing Good Tapsets
2.2. Elements of a Tapset
2.2.1. Tapset Files
2.2.2. Namespace
2.2.3. Comments and Documentation
This chapter describes the upstream guidelines on proper tapset documentation. It also contains information on how to properly document your tapsets, to ensure that they are properly defined in this guide.

2.1. Writing Good Tapsets

The first step to writing good tapsets is to create a simple model of your subject area. For example, a model of the process subsystem might include the following:
Key Data
  • process ID
  • parent process ID
  • process group ID
State Transitions
  • forked
  • exec'd
  • running
  • stopped
  • terminated

Note

Both lists are examples, and are not meant to represent a complete list.
Use your subsystem expertise to find probe points (function entries and exits) that expose the elements of the model, then define probe aliases for those points. Be aware that some state transitions can occur in more than one place. In those cases, an alias can place a probe in multiple locations.
For example, process execs can occur in either the do_execve() or the compat_do_execve() functions. The following alias inserts probes at the beginning of those functions: 
probe kprocess.exec = kernel.function("do_execve"),
kernel.function("compat_do_execve") 
{probe body}
Try to place probes on stable interfaces (i.e., functions that are unlikely to change at the interface level) whenever possible. This will make the tapset less likely to break due to kernel changes. Where kernel version or architecture dependencies are unavoidable, use preprocessor conditionals (see the stap(1) man page for details).
Fill in the probe bodies with the key data available at the probe points. Function entry probes can access the entry parameters specified to the function, while exit probes can access the entry parameters and the return value. Convert the data into meaningful forms where appropriate (e.g., bytes to kilobytes, state values to strings, etc).
You may need to use auxiliary functions to access or convert some of the data. Auxiliary functions often use embedded C to do things that cannot be done in the SystemTap language, like access structure fields in some contexts, follow linked lists, etc. You can use auxiliary functions defined in other tapsets or write your own.
In the following example, copy_process() returns a pointer to the task_struct for the new process. Note that the process ID of the new process is retrieved by calling task_pid() and passing it the task_struct pointer. In this case, the auxiliary function is an embedded C function defined in task.stp. 
probe kprocess.create = kernel.function("copy_process").return 
{
   task = $return
   new_pid = task_pid(task)
}
It is not advisable to write probes for every function. Most SystemTap users will not need or understand them. Keep your tapsets simple and high-level.

2.2. Elements of a Tapset

The following sections describe the most important aspects of writing a tapset. Most of the content herein is suitable for developers who wish to contribute to SystemTap's upstream library of tapsets.

2.2.1. Tapset Files

Tapset files are stored in src/tapset/ of the SystemTap GIT directory. Most tapset files are kept at that level. If you have code that only works with a specific architecture or kernel version, you may choose to put your tapset in the appropriate subdirectory.
Installed tapsets are located in /usr/share/systemtap/tapset/ or /usr/local/share/systemtap/tapset.
Personal tapsets can be stored anywhere. However, to ensure that SystemTap can use them, use -I tapset_directory to specify their location when invoking stap.

2.2.2. Namespace

Probe alias names should take the form tapset_name.probe_name. For example, the probe for sending a signal could be named signal.send.
Global symbol names (probes, functions, and variables) should be unique accross all tapsets. This helps avoid namespace collisions in scripts that use multiple tapsets. To ensure this, use tapset-specific prefixes in your global symbols.
Internal symbol names should be prefixed with an underscore (_).

2.2.3. Comments and Documentation

All probes and functions should include comment blocks that describe their purpose, the data they provide, and the context in which they run (e.g. interrupt, process, etc). Use comments in areas where your intent may not be clear from reading the code.
Note that specially-formatted comments are automatically extracted from most tapsets and included in this guide. This helps ensure that tapset contributors can write their tapset and document it in the same place. The specified format for documenting tapsets is as follows: 
/**
 * probe tapset.name - Short summary of what the tapset does.
 * @argument: Explanation of argument.
 * @argument2: Explanation of argument2. Probes can have multiple arguments.
 *
 * Context:
 * A brief explanation of the tapset context. 
 * Note that the context should only be 1 paragraph short.
 *
 * Text that will appear under "Description."
 *
 * A new paragraph that will also appear under the heading "Description".
 *
 * Header:
 * A paragraph that will appear under the heading "Header".
 **/
For example: 
/**
 * probe vm.write_shared_copy- Page copy for shared page write.
 * @address: The address of the shared write.
 * @zero: Boolean indicating whether it is a zero page
 *         (can do a clear instead of a copy).
 *
 * Context:
 *  The process attempting the write.
 *
 *  Fires when a write to a shared page requires a page copy.  This is
 *  always preceded by a vm.shared_write.
 **/
To override the automatically-generated Synopsis content, use: 
 * Synopsis:
 * New Synopsis string
 *
For example: 
/**
 * probe signal.handle - Fires when the signal handler is invoked
 * @sig: The signal number that invoked the signal handler
 *
 * Synopsis:
 * <programlisting>static int handle_signal(unsigned long sig, siginfo_t *info, struct k_sigaction *ka,
 * sigset_t *oldset, struct pt_regs * regs)</programlisting>
 */
It is recommended that you use the <programlisting> tag in this instance, since overriding the Synopsis content of an entry does not automatically form the necessary tags.
For the purposes of improving the DocBook XML output of your comments, you can also use the following XML tags in your comments:
  • command
  • emphasis
  • programlisting
  • remark (tagged strings will appear in Publican beta builds of the document)

Chapter 3. Context Functions

print_regs — Print a register dump.
execname — Returns the execname of a target process (or group of processes).
pid — Returns the ID of a target process.
tid — Returns the thread ID of a target process.
ppid — Returns the process ID of a target process's parent process.
pgrp — Returns the process group ID of the current process.
sid — Returns the session ID of the current process.
pexecname — Returns the execname of a target process's parent process.
gid — Returns the group ID of a target process.
egid — Returns the effective gid of a target process.
uid — Returns the user ID of a target process.
euid — Return the effective uid of a target process.
cpu — Returns the current cpu number.
pp — Return the probe point associated with the currently running probe handler,
registers_valid — Determines validity of register and u_register in current context.
user_mode — Determines if probe point occurs in user-mode.
is_return — Determines if probe point is a return probe.
target — Return the process ID of the target process.
stack_size — Return the size of the kernel stack.
stack_used — Returns the amount of kernel stack used.
stack_unused — Returns the amount of kernel stack currently available.
uaddr — User space address of current running task. EXPERIMENTAL.
print_stack — Print out stack from string.
probefunc — Return the probe point's function name, if known.
probemod — Return the probe point's module name, if known.
modname — Return the kernel module name loaded at the address.
symname — Return the symbol associated with the given address.
symdata — Return the symbol and module offset for the address.
usymname — Return the symbol of an address in the current task. EXPERIMENTAL!
usymdata — Return the symbol and module offset of an address. EXPERIMENTAL!
print_ustack — Print out stack for the current task from string. EXPERIMENTAL!
print_backtrace — Print stack back trace
backtrace — Hex backtrace of current stack
caller — Return name and address of calling function
caller_addr — Return caller address
print_ubacktrace — Print stack back trace for current task. EXPERIMENTAL!
ubacktrace — Hex backtrace of current task stack. EXPERIMENTAL!
The context functions provide additional information about where an event occurred. These functions can provide information such as a backtrace to where the event occured and the current register values for the processor.

Name

print_regs — Print a register dump.

Synopsis

function print_regs()

Arguments

None

Name

execname — Returns the execname of a target process (or group of processes).

Synopsis

function execname:string()

Arguments

None

Name

pid — Returns the ID of a target process.

Synopsis

function pid:long()

Arguments

None

Name

tid — Returns the thread ID of a target process.

Synopsis

function tid:long()

Arguments

None

Name

ppid — Returns the process ID of a target process's parent process.

Synopsis

function ppid:long()

Arguments

None

Name

pgrp — Returns the process group ID of the current process.

Synopsis

function pgrp:long()

Arguments

None

Name

sid — Returns the session ID of the current process.

Synopsis

function sid:long()

Arguments

None

Description

The session ID of a process is the process group ID of the session leader. Session ID is stored in the signal_struct since Kernel 2.6.0.

Name

pexecname — Returns the execname of a target process's parent process.

Synopsis

function pexecname:string()

Arguments

None

Name

gid — Returns the group ID of a target process.

Synopsis

function gid:long()

Arguments

None

Name

egid — Returns the effective gid of a target process.

Synopsis

function egid:long()

Arguments

None

Name

uid — Returns the user ID of a target process.

Synopsis

function uid:long()

Arguments

None

Name

euid — Return the effective uid of a target process.

Synopsis

function euid:long()

Arguments

None

Name

cpu — Returns the current cpu number.

Synopsis

function cpu:long()

Arguments

None

Name

pp — Return the probe point associated with the currently running probe handler,

Synopsis

function pp:string()

Arguments

None

Description

including alias and wildcard expansion effects

Context

The current probe point.

Name

registers_valid — Determines validity of register and u_register in current context.

Synopsis

function registers_valid:long()

Arguments

None

Description

Return 1 if register and u_register can be used in the current context, or 0 otherwise. For example, registers_valid returns 0 when called from a begin or end probe.

Name

user_mode — Determines if probe point occurs in user-mode.

Synopsis

function user_mode:long()

Arguments

None

Description

Return 1 if the probe point occurred in user-mode.

Name

is_return — Determines if probe point is a return probe.

Synopsis

function is_return:long()

Arguments

None

Description

Return 1 if the probe point is a return probe. Deprecated.

Name

target — Return the process ID of the target process.

Synopsis

function target:long()

Arguments

None

Name

stack_size — Return the size of the kernel stack.

Synopsis

function stack_size:long()

Arguments

None

Name

stack_used — Returns the amount of kernel stack used.

Synopsis

function stack_used:long()

Arguments

None

Description

Determines how many bytes are currently used in the kernel stack.

Name

stack_unused — Returns the amount of kernel stack currently available.

Synopsis

function stack_unused:long()

Arguments

None

Description

Determines how many bytes are currently available in the kernel stack.

Name

uaddr — User space address of current running task. EXPERIMENTAL.

Synopsis

function uaddr:long()

Arguments

None

Description

Returns the address in userspace that the current task was at when the probe occured. When the current running task isn't a user space thread, or the address cannot be found, zero is returned. Can be used to see where the current task is combined with usymname or symdata. Often the task will be in the VDSO where it entered the kernel. FIXME - need VDSO tracking support #10080.

Name

print_stack — Print out stack from string.

Synopsis

function print_stack(stk:string)

Arguments

stk
String with list of hexidecimal addresses.

Description

Perform a symbolic lookup of the addresses in the given string, which is assumed to be the result of a prior call to backtrace.
Print one line per address, including the address, the name of the function containing the address, and an estimate of its position within that function. Return nothing.

Name

probefunc — Return the probe point's function name, if known.

Synopsis

function probefunc:string()

Arguments

None

Name

probemod — Return the probe point's module name, if known.

Synopsis

function probemod:string()

Arguments

None

Name

modname — Return the kernel module name loaded at the address.

Synopsis

function modname:string(addr:long)

Arguments

addr
The address.

Description

Returns the module name associated with the given address if known. If not known it will return the string “<unknown>”. If the address was not in a kernel module, but in the kernel itself, then the string “kernel” will be returned.

Name

symname — Return the symbol associated with the given address.

Synopsis

function symname:string(addr:long)

Arguments

addr
The address to translate.

Description

Returns the (function) symbol name associated with the given address if known. If not known it will return the hex string representation of addr.

Name

symdata — Return the symbol and module offset for the address.

Synopsis

function symdata:string(addr:long)

Arguments

addr
The address to translate.

Description

Returns the (function) symbol name associated with the given address if known, plus the module name (between brackets) and the offset inside the module, plus the size of the symbol function. If any element is not known it will be ommitted and if the symbol name is unknown it will return the hex string for the given address.

Name

usymname — Return the symbol of an address in the current task. EXPERIMENTAL!

Synopsis

function usymname:string(addr:long)

Arguments

addr
The address to translate.

Description

Returns the (function) symbol name associated with the given address if known. If not known it will return the hex string representation of addr.

Name

usymdata — Return the symbol and module offset of an address. EXPERIMENTAL!

Synopsis

function usymdata:string(addr:long)

Arguments

addr
The address to translate.

Description

Returns the (function) symbol name associated with the given address in the current task if known, plus the module name (between brackets) and the offset inside the module (shared library), plus the size of the symbol function. If any element is not known it will be ommitted and if the symbol name is unknown it will return the hex string for the given address.

Name

print_ustack — Print out stack for the current task from string. EXPERIMENTAL!

Synopsis

function print_ustack(stk:string)

Arguments

stk
String with list of hexidecimal addresses for the current task.

Description

Perform a symbolic lookup of the addresses in the given string, which is assumed to be the result of a prior call to ubacktrace for the current task.
Print one line per address, including the address, the name of the function containing the address, and an estimate of its position within that function. Return nothing.

Name

print_backtrace — Print stack back trace

Synopsis

function print_backtrace()

Arguments

None

Description

Equivalent to print_stack(backtrace), except that deeper stack nesting may be supported. Return nothing.

Name

backtrace — Hex backtrace of current stack

Synopsis

function backtrace:string()

Arguments

None

Description

Return a string of hex addresses that are a backtrace of the stack. Output may be truncated as per maximum string length.

Name

caller — Return name and address of calling function

Synopsis

function caller:string()

Arguments

None

Description

Return the address and name of the calling function.

This is equivalent to calling

sprintf(“s 0xx”, symname(caller_addr, caller_addr)) Works only for return probes at this time.

Name

caller_addr — Return caller address

Synopsis

function caller_addr:long()

Arguments

None

Description

Return the address of the calling function. Works only for return probes at this time.

Name

print_ubacktrace — Print stack back trace for current task. EXPERIMENTAL!

Synopsis

function print_ubacktrace()

Arguments

None

Description

Equivalent to print_ustack(ubacktrace), except that deeper stack nesting may be supported. Return nothing.

Name

ubacktrace — Hex backtrace of current task stack. EXPERIMENTAL!

Synopsis

function ubacktrace:string()

Arguments

None

Description

Return a string of hex addresses that are a backtrace of the stack of the current task. Output may be truncated as per maximum string length. Returns empty string when current probe point cannot determine user backtrace.

Chapter 4. Timestamp Functions

get_cycles — Processor cycle count.
Each timestamp function returns a value to indicate when a function is executed. These returned values can then be used to indicate when an event occurred, provide an ordering for events, or compute the amount of time elapsed between two time stamps.

Name

get_cycles — Processor cycle count.

Synopsis

function get_cycles:long()

Arguments

None

Description

Return the processor cycle counter value, or 0 if unavailable.

Chapter 5. Memory Tapset

vm_fault_contains — Test return value for page fault reason
vm.pagefault — Records that a page fault occurred.
vm.pagefault.return — Indicates what type of fault occurred.
addr_to_node — Returns which node a given address belongs to within a NUMA system.
vm.write_shared — Attempts at writing to a shared page.
vm.write_shared_copy — Page copy for shared page write.
vm.mmap — Fires when an mmap is requested.
vm.munmap — Fires when an munmap is requested.
vm.brk — Fires when a brk is requested (i.e. the heap will be resized).
vm.oom_kill — Fires when a thread is selected for termination by the OOM killer.
This family of probe points is used to probe memory-related events. It contains the following probe points:

Name

vm_fault_contains — Test return value for page fault reason

Synopsis

function vm_fault_contains:long(value:long,test:long)

Arguments

value
The fault_type returned by vm.page_fault.return
test
The type of fault to test for (VM_FAULT_OOM or similar)

Name

vm.pagefault — Records that a page fault occurred.

Synopsis

vm.pagefault

Values

write_access
Indicates whether this was a write or read access; 1 indicates a write, while 0 indicates a read.
address
The address of the faulting memory access; i.e. the address that caused the page fault.

Context

The process which triggered the fault

Name

vm.pagefault.return — Indicates what type of fault occurred.

Synopsis

vm.pagefault.return

Values

fault_type
Returns either 0 (VM_FAULT_OOM) for out of memory faults, 2 (VM_FAULT_MINOR) for minor faults, 3 (VM_FAULT_MAJOR) for major faults, or 1 (VM_FAULT_SIGBUS) if the fault was neither OOM, minor fault, nor major fault.

Name

addr_to_node — Returns which node a given address belongs to within a NUMA system.

Synopsis

function addr_to_node:long(addr:long)

Arguments

addr
The address of the faulting memory access.

Name

vm.write_shared — Attempts at writing to a shared page.

Synopsis

vm.write_shared

Values

address
The address of the shared write.

Context

The context is the process attempting the write.

Description

Fires when a process attempts to write to a shared page. If a copy is necessary, this will be followed by a vm.write_shared_copy.

Name

vm.write_shared_copy — Page copy for shared page write.

Synopsis

vm.write_shared_copy

Values

zero
Boolean indicating whether it is a zero page (can do a clear instead of a copy).
address
The address of the shared write.

Context

The process attempting the write.

Description

Fires when a write to a shared page requires a page copy. This is always preceded by a vm.shared_write.

Name

vm.mmap — Fires when an mmap is requested.

Synopsis

vm.mmap

Values

length
The length of the memory segment
address
The requested address

Context

The process calling mmap.

Name

vm.munmap — Fires when an munmap is requested.

Synopsis

vm.munmap

Values

length
The length of the memory segment
address
The requested address

Context

The process calling munmap.

Name

vm.brk — Fires when a brk is requested (i.e. the heap will be resized).

Synopsis

vm.brk

Values

length
The length of the memory segment
address
The requested address

Context

The process calling brk.

Name

vm.oom_kill — Fires when a thread is selected for termination by the OOM killer.

Synopsis

vm.oom_kill

Values

task
The task being killed

Context

The process that tried to consume excessive memory, and thus triggered the OOM.

Chapter 6. IO Scheduler Tapset

ioscheduler.elv_next_request — Fires when a request is retrieved from the request queue
ioscheduler.elv_next_request.return — Fires when a request retrieval issues a return signal
ioscheduler.elv_add_request — A request was added to the request queue
ioscheduler.elv_completed_request — Fires when a request is completed
This family of probe points is used to probe IO scheduler activities. It contains the following probe points:

Name

ioscheduler.elv_next_request — Fires when a request is retrieved from the request queue

Synopsis

ioscheduler.elv_next_request

Values

elevator_name
The type of I/O elevator currently enabled

Name

ioscheduler.elv_next_request.return — Fires when a request retrieval issues a return signal

Synopsis

ioscheduler.elv_next_request.return

Values

req_flags
Request flags
req
Address of the request
disk_major
Disk major number of the request
disk_minor
Disk minor number of the request

Name

ioscheduler.elv_add_request — A request was added to the request queue

Synopsis

ioscheduler.elv_add_request

Values

req_flags
Request flags
req
Address of the request
disk_major
Disk major number of the request
elevator_name
The type of I/O elevator currently enabled
disk_minor
Disk minor number of the request

Name

ioscheduler.elv_completed_request — Fires when a request is completed

Synopsis

ioscheduler.elv_completed_request

Values

req_flags
Request flags
req
Address of the request
disk_major
Disk major number of the request
elevator_name
The type of I/O elevator currently enabled
disk_minor
Disk minor number of the request

Chapter 7. SCSI Tapset

scsi.ioentry — Prepares a SCSI mid-layer request
scsi.iodispatching — SCSI mid-layer dispatched low-level SCSI command
scsi.iodone — SCSI command completed by low level driver and enqueued into the done queue.
scsi.iocompleted — SCSI mid-layer running the completion processing for block device I/O requests
This family of probe points is used to probe SCSI activities. It contains the following probe points:

Name

scsi.ioentry — Prepares a SCSI mid-layer request

Synopsis

scsi.ioentry

Values

disk_major
The major number of the disk (-1 if no information)
device_state
The current state of the device.
disk_minor
The minor number of the disk (-1 if no information)

Name

scsi.iodispatching — SCSI mid-layer dispatched low-level SCSI command

Synopsis

scsi.iodispatching

Values

lun
The lun number
req_bufflen
The request buffer length
host_no
The host number
device_state
The current state of the device.
dev_id
The scsi device id
channel
The channel number
data_direction
The data_direction specifies whether this command is from/to the device. 0 (DMA_BIDIRECTIONAL), 1 (DMA_TO_DEVICE), 2 (DMA_FROM_DEVICE), 3 (DMA_NONE)
request_buffer
The request buffer address

Name

scsi.iodone — SCSI command completed by low level driver and enqueued into the done queue.

Synopsis

scsi.iodone

Values

lun
The lun number
host_no
The host number
device_state
The current state of the device
dev_id
The scsi device id
channel
The channel number
data_direction
The data_direction specifies whether this command is from/to the device.

Name

scsi.iocompleted — SCSI mid-layer running the completion processing for block device I/O requests

Synopsis

scsi.iocompleted

Values

lun
The lun number
host_no
The host number
device_state
The current state of the device
dev_id
The scsi device id
channel
The channel number
data_direction
The data_direction specifies whether this command is from/to the device
goodbytes
The bytes completed.

Chapter 8. Networking Tapset

netdev.receive — Data recieved from network device.
netdev.transmit — Network device transmitting buffer
tcp.sendmsg — Sending a tcp message
tcp.sendmsg.return — Sending TCP message is done
tcp.recvmsg — Receiving TCP message
tcp.recvmsg.return — Receiving TCP message complete
tcp.disconnect — TCP socket disconnection
tcp.disconnect.return — TCP socket disconnection complete
tcp.setsockopt — Call to setsockopt
tcp.setsockopt.return — Return from setsockopt
tcp.receive — Called when a TCP packet is received
udp.sendmsg — Fires whenever a process sends a UDP message
udp.sendmsg.return — Fires whenever an attempt to send a UDP message is completed
udp.recvmsg — Fires whenever a UDP message is received
udp.recvmsg.return — Fires whenever an attempt to receive a UDP message received is completed
udp.disconnect — Fires when a process requests for a UDP disconnection
udp.disconnect.return — UDP has been disconnected successfully
ip_ntop — returns a string representation from an integer IP number
This family of probe points is used to probe the activities of the network device and protocol layers.

Name

netdev.receive — Data recieved from network device.

Synopsis

netdev.receive

Values

protocol
Protocol of recieved packet.
dev_name
The name of the device. e.g: eth0, ath1.
length
The length of the receiving buffer.

Name

netdev.transmit — Network device transmitting buffer

Synopsis

netdev.transmit

Values

protocol
The protocol of this packet.
dev_name
The name of the device. e.g: eth0, ath1.
length
The length of the transmit buffer.
truesize
The size of the the data to be transmitted.

Name

tcp.sendmsg — Sending a tcp message

Synopsis

tcp.sendmsg

Values

name
Name of this probe
size
Number of bytes to send
sock
Network socket

Context

The process which sends a tcp message

Name

tcp.sendmsg.return — Sending TCP message is done

Synopsis

tcp.sendmsg.return

Values

name
Name of this probe
size
Number of bytes sent or error code if an error occurred.

Context

The process which sends a tcp message

Name

tcp.recvmsg — Receiving TCP message

Synopsis

tcp.recvmsg

Values

saddr
A string representing the source IP address
daddr
A string representing the destination IP address
name
Name of this probe
sport
TCP source port
dport
TCP destination port
size
Number of bytes to be received
sock
Network socket

Context

The process which receives a tcp message

Name

tcp.recvmsg.return — Receiving TCP message complete

Synopsis

tcp.recvmsg.return

Values

saddr
A string representing the source IP address
daddr
A string representing the destination IP address
name
Name of this probe
sport
TCP source port
dport
TCP destination port
size
Number of bytes received or error code if an error occurred.

Context

The process which receives a tcp message

Name

tcp.disconnect — TCP socket disconnection

Synopsis

tcp.disconnect

Values

saddr
A string representing the source IP address
daddr
A string representing the destination IP address
flags
TCP flags (e.g. FIN, etc)
name
Name of this probe
sport
TCP source port
dport
TCP destination port
sock
Network socket

Context

The process which disconnects tcp

Name

tcp.disconnect.return — TCP socket disconnection complete

Synopsis

tcp.disconnect.return

Values

ret
Error code (0: no error)
name
Name of this probe

Context

The process which disconnects tcp

Name

tcp.setsockopt — Call to setsockopt

Synopsis

tcp.setsockopt

Values

optstr
Resolves optname to a human-readable format
level
The level at which the socket options will be manipulated
optlen
Used to access values for setsockopt
name
Name of this probe
optname
TCP socket options (e.g. TCP_NODELAY, TCP_MAXSEG, etc)
sock
Network socket

Context

The process which calls setsockopt

Name

tcp.setsockopt.return — Return from setsockopt

Synopsis

tcp.setsockopt.return

Values

ret
Error code (0: no error)
name
Name of this probe

Context

The process which calls setsockopt

Name

tcp.receive — Called when a TCP packet is received

Synopsis

tcp.receive

Values

urg
TCP URG flag
psh
TCP PSH flag
rst
TCP RST flag
dport
TCP destination port
saddr
A string representing the source IP address
daddr
A string representing the destination IP address
ack
TCP ACK flag
syn
TCP SYN flag
fin
TCP FIN flag
sport
TCP source port

Name

udp.sendmsg — Fires whenever a process sends a UDP message

Synopsis

udp.sendmsg

Values

name
The name of this probe
size
Number of bytes sent by the process
sock
Network socket used by the process

Context

The process which sent a UDP message

Name

udp.sendmsg.return — Fires whenever an attempt to send a UDP message is completed

Synopsis

udp.sendmsg.return

Values

name
The name of this probe
size
Number of bytes sent by the process

Context

The process which sent a UDP message

Name

udp.recvmsg — Fires whenever a UDP message is received

Synopsis

udp.recvmsg

Values

name
The name of this probe
size
Number of bytes received by the process
sock
Network socket used by the process

Context

The process which received a UDP message

Name

udp.recvmsg.return — Fires whenever an attempt to receive a UDP message received is completed

Synopsis

udp.recvmsg.return

Values

name
The name of this probe
size
Number of bytes received by the process

Context

The process which received a UDP message

Name

udp.disconnect — Fires when a process requests for a UDP disconnection

Synopsis

udp.disconnect

Values

flags
Flags (e.g. FIN, etc)
name
The name of this probe
sock
Network socket used by the process

Context

The process which requests a UDP disconnection

Name

udp.disconnect.return — UDP has been disconnected successfully

Synopsis

udp.disconnect.return

Values

ret
Error code (0: no error)
name
The name of this probe

Context

The process which requested a UDP disconnection

Name

ip_ntop — returns a string representation from an integer IP number

Synopsis

function ip_ntop:string(addr:long)

Arguments

addr
the ip represented as an integer

Chapter 9. Socket Tapset

socket.send — Message sent on a socket.
socket.receive — Message received on a socket.
socket.sendmsg — Message is currently being sent on a socket.
socket.sendmsg.return — Return from socket.sendmsg.
socket.recvmsg — Message being received on socket
socket.recvmsg.return — Return from Message being received on socket
socket.aio_write — Message send via sock_aio_write
socket.aio_write.return — Conclusion of message send via sock_aio_write
socket.aio_read — Receiving message via sock_aio_read
socket.aio_read.return — Conclusion of message received via sock_aio_read
socket.writev — Message sent via socket_writev
socket.writev.return — Conclusion of message sent via socket_writev
socket.readv — Receiving a message via sock_readv
socket.readv.return — Conclusion of receiving a message via sock_readv
socket.create — Creation of a socket
socket.create.return — Return from Creation of a socket
socket.close — Close a socket
socket.close.return — Return from closing a socket
sock_prot_num2str — Given a protocol number, return a string representation.
sock_prot_str2num — Given a protocol name (string), return the corresponding protocol number.
sock_fam_num2str — Given a protocol family number, return a string representation.
sock_fam_str2num — Given a protocol family name (string), return the corresponding
sock_state_num2str — Given a socket state number, return a string representation.
sock_state_str2num — Given a socket state string, return the corresponding state number.
This family of probe points is used to probe socket activities. It contains the following probe points:

Name

socket.send — Message sent on a socket.

Synopsis

socket.send

Values

success
Was send successful? (1 = yes, 0 = no)
protocol
Protocol value
flags
Socket flags value
name
Name of this probe
state
Socket state value
size
Size of message sent (in bytes) or error code if success = 0
type
Socket type value
family
Protocol family value

Context

The message sender

Name

socket.receive — Message received on a socket.

Synopsis

socket.receive

Values

success
Was send successful? (1 = yes, 0 = no)
protocol
Protocol value
flags
Socket flags value
name
Name of this probe
state
Socket state value
size
Size of message received (in bytes) or error code if success = 0
type
Socket type value
family
Protocol family value

Context

The message receiver

Name

socket.sendmsg — Message is currently being sent on a socket.

Synopsis

socket.sendmsg

Values

protocol
Protocol value
flags
Socket flags value
name
Name of this probe
state
Socket state value
size
Message size in bytes
type
Socket type value
family
Protocol family value

Context

The message sender

Description

Fires at the beginning of sending a message on a socket via the the sock_sendmsg function

Name

socket.sendmsg.return — Return from socket.sendmsg.

Synopsis

socket.sendmsg.return

Values

success
Was send successful? (1 = yes, 0 = no)
protocol
Protocol value
flags
Socket flags value
name
Name of this probe
state
Socket state value
size
Size of message sent (in bytes) or error code if success = 0
type
Socket type value
family
Protocol family value

Context

The message sender.

Description

Fires at the conclusion of sending a message on a socket via the sock_sendmsg function

Name

socket.recvmsg — Message being received on socket

Synopsis

socket.recvmsg

Values

protocol
Protocol value
flags
Socket flags value
name
Name of this probe
state
Socket state value
size
Message size in bytes
type
Socket type value
family
Protocol family value

Context

The message receiver.

Description

Fires at the beginning of receiving a message on a socket via the sock_recvmsg function

Name

socket.recvmsg.return — Return from Message being received on socket

Synopsis

socket.recvmsg.return

Values

success
Was receive successful? (1 = yes, 0 = no)
protocol
Protocol value
flags
Socket flags value
name
Name of this probe
state
Socket state value
size
Size of message received (in bytes) or error code if success = 0
type
Socket type value
family
Protocol family value

Context

The message receiver.

Description

Fires at the conclusion of receiving a message on a socket via the sock_recvmsg function.

Name

socket.aio_write — Message send via sock_aio_write

Synopsis

socket.aio_write

Values

protocol
Protocol value
flags
Socket flags value
name
Name of this probe
state
Socket state value
size
Message size in bytes
type
Socket type value
family
Protocol family value

Context

The message sender

Description

Fires at the beginning of sending a message on a socket via the sock_aio_write function

Name

socket.aio_write.return — Conclusion of message send via sock_aio_write

Synopsis

socket.aio_write.return

Values

success
Was receive successful? (1 = yes, 0 = no)
protocol
Protocol value
flags
Socket flags value
name
Name of this probe
state
Socket state value
size
Size of message received (in bytes) or error code if success = 0
type
Socket type value
family
Protocol family value

Context

The message receiver.

Description

Fires at the conclusion of sending a message on a socket via the sock_aio_write function

Name

socket.aio_read — Receiving message via sock_aio_read

Synopsis

socket.aio_read

Values

protocol
Protocol value
flags
Socket flags value
name
Name of this probe
state
Socket state value
size
Message size in bytes
type
Socket type value
family
Protocol family value

Context

The message sender

Description

Fires at the beginning of receiving a message on a socket via the sock_aio_read function

Name

socket.aio_read.return — Conclusion of message received via sock_aio_read

Synopsis

socket.aio_read.return

Values

success
Was receive successful? (1 = yes, 0 = no)
protocol
Protocol value
flags
Socket flags value
name
Name of this probe
state
Socket state value
size
Size of message received (in bytes) or error code if success = 0
type
Socket type value
family
Protocol family value

Context

The message receiver.

Description

Fires at the conclusion of receiving a message on a socket via the sock_aio_read function

Name

socket.writev — Message sent via socket_writev

Synopsis

socket.writev

Values

protocol
Protocol value
flags
Socket flags value
name
Name of this probe
state
Socket state value
size
Message size in bytes
type
Socket type value
family
Protocol family value

Context

The message sender

Description

Fires at the beginning of sending a message on a socket via the sock_writev function

Name

socket.writev.return — Conclusion of message sent via socket_writev

Synopsis

socket.writev.return

Values

success
Was send successful? (1 = yes, 0 = no)
protocol
Protocol value
flags
Socket flags value
name
Name of this probe
state
Socket state value
size
Size of message sent (in bytes) or error code if success = 0
type
Socket type value
family
Protocol family value

Context

The message receiver.

Description

Fires at the conclusion of sending a message on a socket via the sock_writev function

Name

socket.readv — Receiving a message via sock_readv

Synopsis

socket.readv

Values

protocol
Protocol value
flags
Socket flags value
name
Name of this probe
state
Socket state value
size
Message size in bytes
type
Socket type value
family
Protocol family value

Context

The message sender

Description

Fires at the beginning of receiving a message on a socket via the sock_readv function

Name

socket.readv.return — Conclusion of receiving a message via sock_readv

Synopsis

socket.readv.return

Values

success
Was receive successful? (1 = yes, 0 = no)
protocol
Protocol value
flags
Socket flags value
name
Name of this probe
state
Socket state value
size
Size of message received (in bytes) or error code if success = 0
type
Socket type value
family
Protocol family value

Context

The message receiver.

Description

Fires at the conclusion of receiving a message on a socket via the sock_readv function

Name

socket.create — Creation of a socket

Synopsis

socket.create

Values

protocol
Protocol value
name
Name of this probe
requester
Requested by user process or the kernel (1 = kernel, 0 = user)
type
Socket type value
family
Protocol family value

Context

The requester (see requester variable)

Description

Fires at the beginning of creating a socket.

Name

socket.create.return — Return from Creation of a socket

Synopsis

socket.create.return

Values

success
Was socket creation successful? (1 = yes, 0 = no)
protocol
Protocol value
err
Error code if success == 0
name
Name of this probe
requester
Requested by user process or the kernel (1 = kernel, 0 = user)
type
Socket type value
family
Protocol family value

Context

The requester (user process or kernel)

Description

Fires at the conclusion of creating a socket.

Name

socket.close — Close a socket

Synopsis

socket.close

Values

protocol
Protocol value
flags
Socket flags value
name
Name of this probe
state
Socket state value
type
Socket type value
family
Protocol family value

Context

The requester (user process or kernel)

Description

Fires at the beginning of closing a socket.

Name

socket.close.return — Return from closing a socket

Synopsis

socket.close.return

Values

name
Name of this probe

Context

The requester (user process or kernel)

Description

Fires at the conclusion of closing a socket.

Name

sock_prot_num2str — Given a protocol number, return a string representation.

Synopsis

function sock_prot_num2str:string(proto:long)

Arguments

proto
The protocol number.

Name

sock_prot_str2num — Given a protocol name (string), return the corresponding protocol number.

Synopsis

function sock_prot_str2num:long(proto:string)

Arguments

proto
The protocol name.

Name

sock_fam_num2str — Given a protocol family number, return a string representation.

Synopsis

function sock_fam_num2str:string(family:long)

Arguments

family
The family number.

Name

sock_fam_str2num — Given a protocol family name (string), return the corresponding

Synopsis

function sock_fam_str2num:long(family:string)

Arguments

family
The family name.

Description

protocol family number.

Name

sock_state_num2str — Given a socket state number, return a string representation.

Synopsis

function sock_state_num2str:string(state:long)

Arguments

state
The state number.

Name

sock_state_str2num — Given a socket state string, return the corresponding state number.

Synopsis

function sock_state_str2num:long(state:string)

Arguments

state
The state name.

Chapter 10. Kernel Process Tapset

kprocess.create — Fires whenever a new process is successfully created
kprocess.start — Starting new process
kprocess.exec — Attempt to exec to a new program
kprocess.exec_complete — Return from exec to a new program
kprocess.exit — Exit from process
kprocess.release — Process released
This family of probe points is used to probe process-related activities. It contains the following probe points:

Name

kprocess.create — Fires whenever a new process is successfully created

Synopsis

kprocess.create

Values

new_pid
The PID of the newly created process

Context

Parent of the created process.

Description

Fires whenever a new process is successfully created, either as a result of fork (or one of its syscall variants), or a new kernel thread.

Name

kprocess.start — Starting new process

Synopsis

kprocess.start

Values

None

Context

Newly created process.

Description

Fires immediately before a new process begins execution.

Name

kprocess.exec — Attempt to exec to a new program

Synopsis

kprocess.exec

Values

filename
The path to the new executable

Context

The caller of exec.

Description

Fires whenever a process attempts to exec to a new program.

Name

kprocess.exec_complete — Return from exec to a new program

Synopsis

kprocess.exec_complete

Values

success
A boolean indicating whether the exec was successful
errno
The error number resulting from the exec

Context

On success, the context of the new executable. On failure, remains in the context of the caller.

Description

Fires at the completion of an exec call.

Name

kprocess.exit — Exit from process

Synopsis

kprocess.exit

Values

code
The exit code of the process

Context

The process which is terminating.

Description

Fires when a process terminates. This will always be followed by a kprocess.release, though the latter may be delayed if the process waits in a zombie state.

Name

kprocess.release — Process released

Synopsis

kprocess.release

Values

pid
PID of the process being released
task
A task handle to the process being released

Context

The context of the parent, if it wanted notification of this process' termination, else the context of the process itself.

Description

Fires when a process is released from the kernel. This always follows a kprocess.exit, though it may be delayed somewhat if the process waits in a zombie state.

Chapter 11. Signal Tapset

signal.send — Signal being sent to a process
signal.send.return — Signal being sent to a process completed
signal.checkperm — Check being performed on a sent signal
signal.checkperm.return — Check performed on a sent signal completed
signal.wakeup — Sleeping process being wakened for signal
signal.check_ignored — Checking to see signal is ignored
signal.check_ignored.return — Check to see signal is ignored completed
signal.force_segv — Forcing send of SIGSEGV
signal.force_segv.return — Forcing send of SIGSEGV complete
signal.syskill — Sending kill signal to a process
signal.syskill.return — Sending kill signal completed
signal.sys_tkill — Sending a kill signal to a thread
signal.systkill.return — Sending kill signal to a thread completed
signal.sys_tgkill — Sending kill signal to a thread group
signal.sys_tgkill.return — Sending kill signal to a thread group completed
signal.send_sig_queue — Queuing a signal to a process
signal.send_sig_queue.return — Queuing a signal to a process completed
signal.pending — Examining pending signal
signal.pending.return — Examination of pending signal completed
signal.handle — Signal handler being invoked
signal.handle.return — Signal handler invocation completed
signal.do_action — Examining or changing a signal action
signal.do_action.return — Examining or changing a signal action completed
signal.procmask — Examining or changing blocked signals
signal.flush — Flusing all pending signals for a task
This family of probe points is used to probe signal activities. It contains the following probe points:

Name

signal.send — Signal being sent to a process

Synopsis

signal.send

Values

send2queue
Indicates whether the signal is sent to an existing sigqueue
name
The name of the function used to send out the signal
task
A task handle to the signal recipient
sinfo
The address of siginfo struct
si_code
Indicates the signal type
sig_name
A string representation of the signal
sig
The number of the signal
shared
Indicates whether the signal is shared by the thread group
sig_pid
The PID of the process receiving the signal
pid_name
The name of the signal recipient

Context

The signal's sender.

Name

signal.send.return — Signal being sent to a process completed

Synopsis

signal.send.return

Values

retstr
The return value to either __group_send_sig_info, specific_send_sig_info, or send_sigqueue
send2queue
Indicates whether the sent signal was sent to an existing sigqueue
name
The name of the function used to send out the signal
shared
Indicates whether the sent signal is shared by the thread group.

Context

The signal's sender.

Description

Possible __group_send_sig_info and specific_send_sig_info return values are as follows;
0 -- The signal is sucessfully sent to a process, which means that <1> the signal was ignored by the receiving process, <2> this is a non-RT signal and the system already has one queued, and <3> the signal was successfully added to the sigqueue of the receiving process.
-EAGAIN -- The sigqueue of the receiving process is overflowing, the signal was RT, and the signal was sent by a user using something other than kill.
Possible send_group_sigqueue and send_sigqueue return values are as follows;
0 -- The signal was either sucessfully added into the sigqueue of the receiving process, or a SI_TIMER entry is already queued (in which case, the overrun count will be simply incremented).
1 -- The signal was ignored by the receiving process.
-1 -- (send_sigqueue only) The task was marked exiting, allowing * posix_timer_event to redirect it to the group leader.

Name

signal.checkperm — Check being performed on a sent signal

Synopsis

signal.checkperm

Values

name
Name of the probe point; default value is signal.checkperm
task
A task handle to the signal recipient
sinfo
The address of the siginfo structure
si_code
Indicates the signal type
sig_name
A string representation of the signal
sig
The number of the signal
pid_name
Name of the process receiving the signal
sig_pid
The PID of the process receiving the signal

Name

signal.checkperm.return — Check performed on a sent signal completed

Synopsis

signal.checkperm.return

Values

retstr
Return value as a string
name
Name of the probe point; default value is signal.checkperm

Name

signal.wakeup — Sleeping process being wakened for signal

Synopsis

signal.wakeup

Values

resume
Indicates whether to wake up a task in a STOPPED or TRACED state
state_mask
A string representation indicating the mask of task states to wake. Possible values are TASK_INTERRUPTIBLE, TASK_STOPPED, TASK_TRACED, and TASK_INTERRUPTIBLE.
pid_name
Name of the process to wake
sig_pid
The PID of the process to wake

Name

signal.check_ignored — Checking to see signal is ignored

Synopsis

signal.check_ignored

Values

sig_name
A string representation of the signal
sig
The number of the signal
pid_name
Name of the process receiving the signal
sig_pid
The PID of the process receiving the signal

Name

signal.check_ignored.return — Check to see signal is ignored completed

Synopsis

signal.check_ignored.return

Values

retstr
Return value as a string
name
Name of the probe point; default value is signal.checkperm

Name

signal.force_segv — Forcing send of SIGSEGV

Synopsis

signal.force_segv

Values

sig_name
A string representation of the signal
sig
The number of the signal
pid_name
Name of the process receiving the signal
sig_pid
The PID of the process receiving the signal

Name

signal.force_segv.return — Forcing send of SIGSEGV complete

Synopsis

signal.force_segv.return

Values

retstr
Return value as a string
name
Name of the probe point; default value is force_sigsegv

Name

signal.syskill — Sending kill signal to a process

Synopsis

signal.syskill

Values

sig
The specific signal sent to the process
pid
The PID of the process receiving the signal

Name

signal.syskill.return — Sending kill signal completed

Synopsis

signal.syskill.return

Values

None

Name

signal.sys_tkill — Sending a kill signal to a thread

Synopsis

signal.sys_tkill

Values

sig_name
The specific signal sent to the process
sig
The specific signal sent to the process
pid
The PID of the process receiving the kill signal

Description

The tkill call is analogous to kill(2), except that it also allows a process within a specific thread group to be targetted. Such processes are targetted through their unique thread IDs (TID).

Name

signal.systkill.return — Sending kill signal to a thread completed

Synopsis

signal.systkill.return

Values

None

Name

signal.sys_tgkill — Sending kill signal to a thread group

Synopsis

signal.sys_tgkill

Values

sig_name
A string representation of the signal
sig
The specific kill signal sent to the process
pid
The PID of the thread receiving the kill signal
tgid
The thread group ID of the thread receiving the kill signal

Description

The tgkill call is similar to tkill, except that it also allows the caller to specify the thread group ID of the thread to be signalled. This protects against TID reuse.

Name

signal.sys_tgkill.return — Sending kill signal to a thread group completed

Synopsis

signal.sys_tgkill.return

Values

None

Name

signal.send_sig_queue — Queuing a signal to a process

Synopsis

signal.send_sig_queue

Values

sigqueue_addr
The address of the signal queue
sig_name
A string representation of the signal
sig
The queued signal
pid_name
Name of the process to which the signal is queued
sig_pid
The PID of the process to which the signal is queued

Name

signal.send_sig_queue.return — Queuing a signal to a process completed

Synopsis

signal.send_sig_queue.return

Values

retstr
Return value as a string

Name

signal.pending — Examining pending signal

Synopsis

signal.pending

Values

sigset_size
The size of the user-space signal set
sigset_add
The address of the user-space signal set (sigset_t)

Description

This probe is used to examine a set of signals pending for delivery to a specific thread. This normally occurs when the do_sigpending kernel function is executed.

Name

signal.pending.return — Examination of pending signal completed

Synopsis

signal.pending.return

Values

retstr
Return value as a string

Name

signal.handle — Signal handler being invoked

Synopsis

signal.handle

Values

regs
The address of the kernel-mode stack area
sig_code
The si_code value of the siginfo signal
sig_mode
Indicates whether the signal was a user-mode or kernel-mode signal
sinfo
The address of the siginfo table
oldset_addr
The address of the bitmask array of blocked signals
sig
The signal number that invoked the signal handler
ka_addr
The address of the k_sigaction table associated with the signal

Name

signal.handle.return — Signal handler invocation completed

Synopsis

signal.handle.return

Values

retstr
Return value as a string

Name

signal.do_action — Examining or changing a signal action

Synopsis

signal.do_action

Values

sa_mask
The new mask of the signal
oldsigact_addr
The address of the old sigaction struct associated with the signal
sig
The signal to be examined/changed
sa_handler
The new handler of the signal
sigact_addr
The address of the new sigaction struct associated with the signal

Name

signal.do_action.return — Examining or changing a signal action completed

Synopsis

signal.do_action.return

Values

retstr
Return value as a string

Name

signal.procmask — Examining or changing blocked signals

Synopsis

signal.procmask

Values

how
Indicates how to change the blocked signals; possible values are SIG_BLOCK=0 (for blocking signals), SIG_UNBLOCK=1 (for unblocking signals), and SIG_SETMASK=2 for setting the signal mask.
oldsigset_addr
The old address of the signal set (sigset_t)
sigset
The actual value to be set for sigset_t
sigset_addr
The address of the signal set (sigset_t) to be implemented

Name

signal.flush — Flusing all pending signals for a task

Synopsis

signal.flush

Values

task
The task handler of the process performing the flush
pid_name
The name of the process associated with the task performing the flush
sig_pid
The PID of the process associated with the task performing the flush

Revision History

Revision History
Revision 1.0Wed Jun 17 2009Don Domingo
building book in RHEL