Crash Compatibility

drgn provides a compatibility mode emulating the crash utility. Many commands have been ported from crash. Output is not byte-identical, but it generally closely resembles crash output.

These commands can be run directly from the drgn CLI as subcommands of the crash command:

>>> %crash sys
KERNEL: ...

Crash commands take an additional --drgn option instructing them to print example drgn code that does the equivalent of the command. This is useful for learning about drgn helpers and APIs. It can also be used to generate a template for doing something more advanced than the command supports. You can copy and paste the output or even write it to a file and edit it before running it:

>>> %crash mount --drgn > mount.py
>>> %sh $EDITOR mount.py
>>> %source mount.py

Interactive Crash Prompt

Calling the crash command with no arguments enters an interactive prompt where crash commands can be called directly:

>>> %crash
%crash> sys
KERNEL: ...
%crash>

drgn code can be executed from the interactive crash prompt with the drgn command:

%crash> drgn stack_trace(1)[0]["next"].pid
(pid_t)0

Calling the drgn command with no arguments returns to the drgn CLI:

%crash> drgn
>>>

The interactive prompt can also be entered directly from a shell with the drgn-crash script:

$ drgn-crash
KERNEL: ...
%crash>

Commands

*

shortcut for struct or union

Synopsis

* [struct or union command arguments]

Description

This is a shortcut that allows typing, e.g., *list_head instead of struct list_head. Note that if the type name is not also the name of a command, then the * can also be omitted, e.g., list_head.

ascii

translate a hexadecimal value to ASCII

Synopsis

ascii [--drgn] [value …]

Description

Translates 32-bit or 64-bit hexadecimal values to ASCII. If no argument is entered, an ASCII chart is displayed.

Positional Arguments

value

hexadecimal value

Options

--drgn

print how to do the equivalent operation using drgn APIs

bpf

display loaded eBPF programs and maps

Synopsis

bpf [-p PROG_ID] [--drgn]

Options

-p PROG_ID

display additional information for the specified BPF program ID

--drgn

print how to do the equivalent operation using drgn APIs

bt

print stack traces

Synopsis

bt [pid|task [pid|task …] | -c CPUS | -a | -p] [-f | -F] [-l] [-d] [-V] [--drgn]

Description

Print the kernel stack trace for a given PID or task

If no PID or task is given, print the stack trace for the current context task.

Positional Arguments

pid|task

print stack trace for task(s), given as a decimal process ID or hexadecimal task_struct address.

Options

-c CPUS

print stack trace for one or more CPUs, which can be specified using the format ‘3’, ‘1,8,9’, ‘1-23’, or ‘1,8,9-14’.

-a

print stack trace for all CPUs

-p

print stack trace for the panic task

-f

display all stack data contained in a frame

-F

similar to -f, except that the stack data is displayed symbolically where appropriate; if the stack data references a slab cache object, the name of the slab cache will be displayed in brackets. If -F is entered twice, and the stack data references a slab cache object, then both the address and the name of the slab cache will be displayed in brackets

-l

show file and line number of each stack trace text location

-d

format the stack frames in drgn’s style rather than crash’s

-V

print any local variable values which drgn can determine

--drgn

print how to do the equivalent operation using drgn APIs

btop

bytes to page

Synopsis

btop [--drgn] address [address …]

Description

Convert byte numbers (usually physical addresses) to page numbers.

Positional Arguments

address

hexadecimal byte number/physical address

Options

--drgn

print how to do the equivalent operation using drgn APIs

dev

devices

Synopsis

dev [-i | -p | -d | -D] [--drgn]

Options

--drgn

print how to do the equivalent operation using drgn APIs

Type

What type of devices to display. If not given, display registered character and block device majors.

-i

display I/O port regions

-p

display PCI devices

-d

display all disks and their number of in-progress requests

-D

like -d, but only display disks that have in-progress requests

drgn

run drgn code or enter drgn interactive mode

Synopsis

drgn [code]

Description

If code is given, execute the given drgn Python code, up to the first shell redirection or pipeline.

Otherwise, enter drgn’s interactive mode.

eval

evaluate an expression

Synopsis

eval [-b] [-l] [–drgn] (expression)

Description

Evaluate an expression and print the result in various formats.

Positional Arguments

expression

expression to evaluate.

Expressions are of the form value or value operator value, where value is a number optionally prefixed by zero or more unary operators and optionally suffixed by a unit.

Numbers may be decimal or hexadecimal. The “0x” prefix is optional for hexadecimal numbers.

The following binary operators are supported:

+  -  &  |  ^  *  %  /  <<  >>

The following unary operators are supported:

- ~

Units may be “K” or “k” to multiply by 1024, “M” or “m” to multiply by 1024*1024, and “G” or “g” to multiply by 1024*1024*1024.

Expressions may be enclosed in parentheses. Parentheses are only required when using the |, <<, or >> operators.

Options

-b

show which bits are set in the result, where 0 is the least significant bit

-l

use 64-bit values even on 32-bit architectures

--drgn

print how to do the equivalent operation using drgn APIs

exit

exit session

Synopsis

exit

files

file information

Synopsis

files [-d DENTRY | -p INODE | pid|task [pid|task …]] [-c] [-R REFERENCE] [--drgn]

Description

Show file information. By default, display the root directory, current working directory, and all open files of one or more tasks, including the file descriptor, file structure, dentry, inode, file type, and path.

Positional Arguments

pid|task

display open files for this task, given as either a decimal process ID or a hexadecimal task_struct address. May be given multiple times. Defaults to the current context

Options

-d DENTRY

display the inode, super block, file type, and full path of a dentry, given as a hexadecimal address

-p INODE

display the pages in the page cache of an inode, given as a hexadecimal address

-c

for each open file, display the i_mapping and number of cached pages instead of the file structure and dentry

-R REFERENCE

search for references to this file descriptor, path, or dentry, inode, address_space, or file structure address

--drgn

print how to do the equivalent operation using drgn APIs

foreach

run command on multiple tasks

Synopsis

foreach [--drgn] [pid | task | name …] [kernel | user | gleader] [active] [state] command [-option …]

Description

Run the given command on all tasks matching the given constraints (or all tasks in the system if no constraints are given).

Positional Arguments

pid

run the command on the task with this decimal process ID

task

run the command on the task with this hexadecimal task_struct address

name

run the command on tasks with the given name. May be prefixed with \ to disambiguate it as a literal command name. If single-quoted ('), then it is treated as a regular expression

kernel

run the command on kernel threads

user

run the command on user tasks

gleader

run the command on thread group leaders

active

run the command on the active task on each CPU

state

run the command on tasks in this state (“R”, “D”, etc.)

command

run this command on the selected tasks. Currently, bt, files, ps, set, sig, task, vm, and vtop are supported

Options

-option

additional option to pass to the command

--drgn

print how to do the equivalent operation using drgn APIs

help

get help

Synopsis

help [command …]

Description

Print help about one or more commands.

If no commands are given, this lists available commands and prints general help.

Positional Arguments

command

command to get help about, or all for all commands

ipcs

System V IPC

Synopsis

ipcs [-s] [-m] [-q] [-n pid|task] [--drgn] [id|addr …]

Positional Arguments

id|addr

search for IPC instances with the given decimal identifier or hexadecimal kernel address. May be given multiple times

Options

-n pid|task

search in the IPC namespace of a task, given as either a decimal process ID or a hexadecimal task_struct address. Defaults to the IPC namespace of the current context

--drgn

print how to do the equivalent operation using drgn APIs

Types

IPC types to display. If none are given, all three are displayed.

-s

display semaphore arrays

-m

display shared memory segments

-q

display message queues

irq

interrupt requests/descriptors

Synopsis

irq [-u | -d | -b | -a | -s | number [number …]] [-c CPU] [--drgn]

Description

Show interrupt information. By default, display all interrupt descriptors.

Positional Arguments

number

display the interrupt descriptor for the given IRQ number. May be given multiple times

Options

-u

display only allocated interrupt descriptors

-d

display the x86 IDT (interrupt descriptor table)

-b

display softirqs (a.k.a. bottom half)

-a

display CPU affinity for in-use interrupts

-s

display statistics for in-use interrupts

-c CPU

when used with -s, restrict the output to one or more CPUs, which may be a comma-separated string of CPU numbers or ranges (e.g., ‘0,3-4’)

--drgn

print how to do the equivalent operation using drgn APIs

kmem

kernel memory

Synopsis

kmem [-f | -F | -i | -v | -V | -n | -z | -o | -h | -p | -m PAGE_MEMBERS | -s | -g [FLAGS]] [-I NAME[,NAME…]] [--drgn] [name …] [address …]

Description

Display information about various parts of the memory management subsystem.

Positional Arguments

name

when used with -s, only display the slab caches with the given names

address

addresses to identify as symbols, tasks, task stacks, vmalloc allocations, pages, and/or slab objects. Can be combined with -v, -p, -m, or -s to limit the search to their respective types

Options

-f

display and verify page allocator free lists

-F

like -f, but also display each page on the free lists

-i

display general memory usage information

-v

display memory regions allocated with vmalloc()/vmap()

-V

display zone, node, NUMA, and VM event statistics

-n

display NUMA nodes, SPARSEMEM sections, and memory blocks

-z

display per-zone memory statistics

-o

display each CPU’s per-CPU offset (the value added to convert a per-CPU symbol to a virtual address)

-h

display HugeTLB state

-p

display every valid struct page, including its physical address, mapping, index, refcount, and flags

-m PAGE_MEMBERS

display the given comma-separated members of every valid struct page

-s

display an overview of slab caches

-g [FLAGS]

display the flags set on a hexadecimal page flags value, or display all of the possible flags if no value is given

-I NAME[,NAME...]

when used with -s, comma-separated list of names of slab caches to ignore

--drgn

print how to do the equivalent operation using drgn APIs

list

linked list contents

Synopsis

list [-o OFFSET] [-s struct_name[.member[,member]]] [-l OFFSET] [-H | -h] [-O OFFSET] [-r] [-e END] [-x] [-d] [--drgn] start

Positional Arguments

start

hexadecimal address of first list entry (but see -H, -h, and -O)

Options

-o OFFSET

offset from a list entry to the pointer to the next entry, as either a number of bytes or a struct_name.member. This can also be passed as a positional argument (i.e., without “-o”) unless the offset could be confused for a kernel virtual address. Defaults to 0

-s struct_name[.member[,member]], -S struct_name[.member[,member]]

type name of list entries. May include one or more comma-separated members (each of which can be nested and include array subscripts) to limit the output to those members

-l OFFSET

only used with -s. Cannot be used with -o. Offset from a list entry to the list_head or similar structure linking entries together, as either a number of bytes or a struct_name.member

-H

treat start as the address of an anchor list_head (e.g., a standalone LIST_HEAD())

-h

treat start as the address of a list_head embedded in a list entry

-O OFFSET

only used with -h. Treat start as the address of a structure that embeds an anchor list_head at this offset, given as either a number of bytes or a struct_name.member

-r

with -h or -H, iterate in reverse order using list_head.prev

-e END

hexadecimal address where to stop iterating in addition to the defaults of NULL, the start address, the address of the first entry, and the address of the current entry

-x

output integers in hexadecimal format regardless of the default

-d

output integers in decimal format regardless of the default

--drgn

print how to do the equivalent operation using drgn APIs

log

Dump kernel dmesg

Synopsis

log [-T | -t] [--drgn]

Options

-T

Dump kernel dmesg in human readable time

-t

Dump kernel dmesg without timestamp

--drgn

print how to do the equivalent operation using drgn APIs

mod

module information and loading debugging symbols

Synopsis

mod [-s MODULE [FILE …] | -S [DIRECTORY] | -t] [--drgn]

Options

-s MODULE [FILE ...]

load debugging symbols for the given module from the given file, or from the default locations if no file is given

-S [DIRECTORY]

load debugging symbols for all modules from the given directory, or from the default locations if no directory is given

-t

display tainted modules

--drgn

print how to do the equivalent operation using drgn APIs

mount

mounted filesystems

Synopsis

mount [-n pid|task] [--drgn]

Description

List mounted filesystems.

Options

-n pid|task

list mounted filesystems in the namespace of a task, given as either a decimal process ID or a hexadecimal task_struct address. Defaults to the mount namespace of the current context

--drgn

print how to do the equivalent operation using drgn APIs

p

print the value of an object

Synopsis

p [-x] [-d] [--drgn] object[:cpuspec]

Positional Arguments

object[:cpuspec]

object to print. This may include member accesses and array subscripts. It does not support arbitrary expressions yet. For per-cpu variables, this may also contain a colon (‘:’) followed by a specification of which CPUs to print, which may be a comma-separated string of CPU numbers or ranges (e.g., ‘0,3-4’), ‘a’ or ‘all’ (meaning all possible CPUs), or an empty string (meaning the CPU of the current context)

Options

-x

output integers in hexadecimal format regardless of the default

-d

output integers in decimal format regardless of the default

--drgn

print how to do the equivalent operation using drgn APIs

ps

process information

Synopsis

ps [-k | -u] [-G] [-y POLICY] [-A] [-s | -p | -c | -t | -l | -m | -a | -g | -r | -S] [-C CPU] [-H] [--drgn] [pid|task|command …]

Description

display process status information

Positional Arguments

pid|task|command

display only this task, given as a decimal process ID, hexadecimal task_struct, single- quoted (') regular expression matching command names, or a literal command name (optionally prefixed with \ to disambiguate it). May be given multiple times

Options

-k

only display kernel threads

-u

only display user tasks

-G

only display the thread group leader in each thread group

-y POLICY

only display tasks with the given scheduling policy, as a comma-separated list of the following (case-insensitive) policy names or their integer values:

NORMAL or OTHER (0) FIFO (1) RR (2) BATCH (3) IDLE (5) DEADLINE (6) EXT (7)

-A

display only the active task on each CPU

-s

display the kernel stack pointer instead of the task_struct

-p

display the parental hierarchy of selected tasks

-c

display the children of selected tasks

-t

display the task run time, start time, cumulative user time, and cumulative system time

-l

display the last_arrival timestamp of selected tasks, and sort from most-recent to least-recent

-m

like -l, but display the difference between the current runqueue clock and the last_arrival timestamp as “days hours:minutes:seconds.milliseconds”

-a

display the command line arguments and environment variables of selected userspace tasks

-g

display threads in the thread groups of selected tasks and group threads by thread group

-r

display resource limits (rlimits) of selected tasks

-S

display a summary of the number of selected tasks in each task state

-C CPU

for -l or -m, only display tasks on the given CPUs, which may be a comma-separated string of CPU numbers or ranges (e.g., ‘0,3-4’), and group selected tasks by CPU

-H

do not print a header line

--drgn

print how to do the equivalent operation using drgn APIs

ptob

page to bytes

Synopsis

ptob [--drgn] pfn [pfn …]

Description

Convert page frame numbers to byte numbers (physical addresses).

Positional Arguments

pfn

page frame number

Options

--drgn

print how to do the equivalent operation using drgn APIs

ptov

physical or per-CPU to virtual

Synopsis

ptov [--drgn] address|offset:cpuspec [address|offset:cpuspec …]

Description

This command translates a hexadecimal physical address into a kernel virtual address. Alternatively, a hexadecimal per-cpu offset and cpu specifier will be translated into kernel virtual addresses for each cpu specified.

Positional Arguments

address|offset:cpuspec

hexadecimal physical address or hexadecimal per-CPU offset and CPU specifier

Options

--drgn

print how to do the equivalent operation using drgn APIs

rd

read memory

Synopsis

rd [-p | -u] [-d | -D] [-s] [-S] [-x] [-8 | -16 | -32 | -64 | -a] [-N] [-R] [-o OFFSET] [-e END] [-r RAW] [--drgn] address|symbol [count]

Description

This command displays the contents of memory, formatted in several different ways.

Positional Arguments

address|symbol

starting hexadecimal address, or symbol of starting address

count

decimal number of memory locations to display (default: 1)

Options

-p

address argument is a physical address

-u

address argument is a user virtual address; this is only required on processors or configurations where user and kernel virtual address spaces overlap, such as s390x, or 32-bit processors with 4G:4G kernel configurations. In other cases, this can still be used as a hint.

-d

display output in signed decimal format (default is hexadecimal)

-D

display output in unsigned decimal format (default is hexadecimal)

-s

displays output symbolically where appropriate

-S

displays output symbolically where appropriate; if the memory contents reference a slab cache object, the name of the slab cache will be displayed in brackets. If -S is entered twice, and the memory contents reference a slab cache object, both the memory contents and the name of the slab cache will be displayed in brackets

-x

do not display ASCII translation at the end of each line

-8

display output in 8-bit values

-16

display output in 16-bit values

-32

display output in 32-bit values (default on 32-bit machines)

-64

display output in 64-bit values (default on 64-bit machines)

-a

display output in ASCII characters if it contains printable ASCII characters

-N

display output in network byte order

-R

display memory in reverse order; memory will be displayed up to and including the address argument, requiring the count argument to be greater than 1 to display memory before the specified address. Conflicts with -e.

-o OFFSET

offset applied to the starting address

-e END

display memory until reaching this hexadecimal address

-r RAW

dumps raw data to the specified output file; the number of bytes that are copied to the file must be specified either by a count argument or by the -e option

--drgn

print how to do the equivalent operation using drgn APIs

runq

CPU scheduler run queues

Synopsis

runq [-t | -T | -m | -g] [-c CPU] [--drgn]

Description

By default, display the tasks on each CPU’s runqueue.

Options

-t

display the timestamp of each CPU’s runqueue and the timestamp of the active task on each CPU

-T

display the difference between the timestamp of each CPU’s runqueue relative to the runqueue with the highest timestamp

-m

display the amount of time that the active task on each CPU has been running

-g

display the task_group hierarchy on each CPU’s runqueue

-c CPU

restrict the output to one or more CPUs, which may be a comma-separated string of CPU numbers or ranges (e.g., ‘0,3-4’)

--drgn

print how to do the equivalent operation using drgn APIs

set

set current context or configuration

Synopsis

set [pid | task | -p | -c CPU | option [value]] [--drgn]

Description

Set/show the default context used by commands that target a task, or set/show configuration.

If no options are given, then the current context is displayed.

If given a configuration option name and a value, then the option is set to that value. If given a configuration option name only, then the current value is shown. The following options and values are supported:

  • scroll on | off: enable (the default) or disable scrolling of long output.

  • scroll less | more: set the pager program. The default is less.

  • radix 10 | 16: set the default integer output base. The default is 10.

Positional Arguments

pid

set the current context to the task with the given decimal process ID

task

set the current context to the task with the hexadecimal task_struct address

option

option to get or set

value

value to set option to

Options

-c CPU

set the current context to the active task on the given CPU

-p

set the current context to the task that crashed (for core dumps) or the drgn process itself (for live kernels)

--drgn

print how to do the equivalent operation using drgn APIs

sig

signal handling

Synopsis

sig [-g | -l | -s SIGSET] [--drgn] [pid|task …]

Positional Arguments

pid|task

display signal handlers and pending signals for this task, given as either a decimal process ID or a hexadecimal task_struct address. May be given multiple times. Defaults to the current context

Options

-g

display pending signals for all threads

-l

display all known signal numbers and names

-s SIGSET

translate a hexadecimal signal set into a list of signal names

--drgn

print how to do the equivalent operation using drgn APIs

struct

structure contents

Synopsis

struct [-l OFFSET] [-x] [-d] [-c COUNT] [--drgn] struct_name[.member[,member]] [address_or_symbol[:cpuspec]] [count]

Positional Arguments

struct_name[.member[,member]]

name of structure type; one or more comma-separated members (each of which can be nested and include array subscripts) may also be given to limit the output to those members

address_or_symbol[:cpuspec]

hexadecimal address or symbol name of structure. If not given, the type and its size are printed instead. For per-cpu variables, this may also contain a colon (‘:’) followed by a specification of which CPUs to print, which may be a comma-separated string of CPU numbers or ranges (e.g., ‘0,3-4’), ‘a’ or ‘all’ (meaning all possible CPUs), or an empty string (meaning the CPU of the current context)

count

number of consecutive structures

Options

-l OFFSET

offset from the beginning of the desired structure to the given address or symbol, either as a number of bytes or a struct_name.member

-x

output integers in hexadecimal format regardless of the default

-d

output integers in decimal format regardless of the default

-c COUNT

number of consecutive structures

--drgn

print how to do the equivalent operation using drgn APIs

swap

list swap devices

Synopsis

swap [--drgn]

Options

--drgn

print how to do the equivalent operation using drgn APIs

sym

symbol table lookup

Synopsis

sym (-l | -q STRING | name|address [name|address …]) [-p] [-n] [--drgn]

Positional Arguments

name|address

symbol name or hexadecimal address to search for. May be given multiple times

Options

-l

display all symbols and their values

-q STRING

display all symbols whose name contains STRING. May be given multiple times

-p

display the target symbol and the previous symbol

-n

display the target symbol and the next symbol

--drgn

print how to do the equivalent operation using drgn APIs

sys

system information

Synopsis

sys [--drgn] [config]

Positional Arguments

config

print kernel configuration (requires CONFIG_IKCONFIG)

Options

--drgn

print how to do the equivalent operation using drgn APIs

task

task_struct and thread_info contents

Synopsis

task [-R member[,member]] [-x] [-d] [--drgn] [pid|task …]

Positional Arguments

pid|task

display this task, given as either a decimal process ID or a hexadecimal task_struct address. May be given multiple times. Defaults to the current context

Options

-R member[,member]

display only these task_struct members, given as a comma-separated list. Each member can be nested and include array subscripts. The -R is optional

-x

output integers in hexadecimal format regardless of the default

-d

output integers in decimal format regardless of the default

--drgn

print how to do the equivalent operation using drgn APIs

timer

list kernel timers

Synopsis

timer [-r] [-C CPU] [--drgn]

Options

-r

display high-resolution timers (hrtimers)

-C CPU

restrict the output to one or more CPUs, which may be a comma-separated string of CPU numbers or ranges (e.g., ‘0,3-4’)

--drgn

print how to do the equivalent operation using drgn APIs

tree

red-black tree, radix tree, XArray, or maple tree contents

Synopsis

tree [-t {rbtree,radix,xarray,maple}] [-r OFFSET] [-o OFFSET] [-s struct_name[.member[,member]]] [-l] [-x] [-d] [--drgn] start

Positional Arguments

start

address or symbol name of the rb_root, radix_tree_root, xarray, or maple_tree (or the structure containing it if -r is used)

Options

-t {rbtree,radix,xarray,maple}

type of tree. This may also be abbreviated: “rb” for “rbtree”, “ra” for “radix”, “x” for “xarray”, or “m” for “maple”. Defaults to rbtree

-r OFFSET

treat start as the address of a structure containing the tree root at the given offset as either a number of bytes or a struct_name.member

-o OFFSET

for red-black trees, the offset of the rb_node in its containing structure as either a number of bytes or a struct_name.member. Defaults to 0

-s struct_name[.member[,member]], -S struct_name[.member[,member]]

type name of tree entries. May include one or more comma-separated members (each of which can be nested and include array subscripts) to limit the output to those members

-l

for red-black trees, print entries in sorted order instead of the default pre-order traversal

-x

output integers in hexadecimal format regardless of the default

-d

output integers in decimal format regardless of the default

--drgn

print how to do the equivalent operation using drgn APIs

union

union contents

Synopsis

union [-l OFFSET] [-x] [-d] [-c COUNT] [--drgn] union_name[.member[,member]] [address_or_symbol[:cpuspec]] [count]

Positional Arguments

union_name[.member[,member]]

name of union type; one or more comma-separated members (each of which can be nested and include array subscripts) may also be given to limit the output to those members

address_or_symbol[:cpuspec]

hexadecimal address or symbol name of union. If not given, the type and its size are printed instead. For per-cpu variables, this may also contain a colon (‘:’) followed by a specification of which CPUs to print, which may be a comma-separated string of CPU numbers or ranges (e.g., ‘0,3-4’), ‘a’ or ‘all’ (meaning all possible CPUs), or an empty string (meaning the CPU of the current context)

count

number of consecutive unions

Options

-l OFFSET

offset from the beginning of the desired union to the given address or symbol, either as a number of bytes or a union_name.member

-x

output integers in hexadecimal format regardless of the default

-d

output integers in decimal format regardless of the default

-c COUNT

number of consecutive unions

--drgn

print how to do the equivalent operation using drgn APIs

vm

virtual memory

Synopsis

vm [--drgn] [pid|task …]

Description

This command displays basic virtual memory information of a context, consisting of a pointer to its mm_struct and page directory, its RSS and total virtual memory size; and a list of pointers to each vm_area_struct, its starting and ending address, vm_flags value, and file pathname. If no arguments are entered, the current context is used.

Positional Arguments

pid|task

one or more process PIDs or hexadecimal task_struct pointers

Options

--drgn

print how to do the equivalent operation using drgn APIs

vtop

virtual to physical address

Synopsis

vtop [-u | -k] [-c TASK] [--drgn] address [address …]

Positional Arguments

address

hexadecimal virtual address

Options

-c TASK

PID or hexadecimal task_struct pointer of task whose address space should be used for translating virtual addresses

--drgn

print how to do the equivalent operation using drgn APIs

Address Space

In some kernel configurations, whether an address belongs to kernel space or user space can be determined from only its value. In those cases, this command will automatically determine whether the address belongs to kernel or user space.

In other configurations (including s390x, SPARC, and 4G:4G), this is not possible, and one of these options is required.

-u

treat addresses as user space virtual addresses

-k

treat addresses as kernel space virtual addresses

waitq

list tasks on a wait queue

Synopsis

waitq (symbol | address | struct.member struct_addr) [--drgn]

Positional Arguments

symbol

symbol name of wait queue

address

hexadecimal address of wait queue

struct.member

name of structure type containing a wait queue member with the given name

struct_addr

address of structure containing wait queue member

Options

--drgn

print how to do the equivalent operation using drgn APIs

whatis

search symbol table for data or type information

Synopsis

whatis [--drgn] name

Description

Displays the definition of structures, unions, typedefs or text/data symbols.

Positional Arguments

name

struct/union/typedef/enum/type name or symbol name

Options

--drgn

print how to do the equivalent operation using drgn APIs