Documentation/admin-guide/kdump/vmcoreinfo.rst
Source file repositories/reference/linux-study-clean/Documentation/admin-guide/kdump/vmcoreinfo.rst
File Facts
- System
- Linux kernel
- Corpus path
Documentation/admin-guide/kdump/vmcoreinfo.rst- Extension
.rst- Size
- 16974 bytes
- Lines
- 597
- Domain
- Support Tooling And Documentation
- Bucket
- Documentation
- Inferred role
- Support Tooling And Documentation: documentation
- Status
- atlas-only
Why This File Exists
Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.
- Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.
- Uses kernel synchronization; read lock ordering, sleepability, and interrupt context assumptions before translating.
- Allocates kernel memory; connect allocation flags and lifetime to context constraints.
- Defines or uses C structs; map object ownership, embedded links, reference counts, and lock ownership.
Dependency Surface
- No C-style include directives detected by the generator.
Detected Declarations
- No top-level syscall, struct, function, initcall, or export declaration detected by the generator.
Annotated Snippet
==========
VMCOREINFO
==========
What is it?
===========
VMCOREINFO is a special ELF note section. It contains various
information from the kernel like structure size, page size, symbol
values, field offsets, etc. These data are packed into an ELF note
section and used by user-space tools like crash and makedumpfile to
analyze a kernel's memory layout.
Common variables
================
init_uts_ns.name.release
------------------------
The version of the Linux kernel. Used to find the corresponding source
code from which the kernel has been built. For example, crash uses it to
find the corresponding vmlinux in order to process vmcore.
PAGE_SIZE
---------
The size of a page. It is the smallest unit of data used by the memory
management facilities. It is usually 4096 bytes of size and a page is
aligned on 4096 bytes. Used for computing page addresses.
init_uts_ns
-----------
The UTS namespace which is used to isolate two specific elements of the
system that relate to the uname(2) system call. It is named after the
data structure used to store information returned by the uname(2) system
call.
User-space tools can get the kernel name, host name, kernel release
number, kernel version, architecture name and OS type from it.
(uts_namespace, name)
---------------------
Offset of the name's member. Crash Utility and Makedumpfile get
the start address of the init_uts_ns.name from this.
node_online_map
---------------
An array node_states[N_ONLINE] which represents the set of online nodes
in a system, one bit position per node number. Used to keep track of
which nodes are in the system and online.
swapper_pg_dir
--------------
The global page directory pointer of the kernel. Used to translate
virtual to physical addresses.
_stext
------
Defines the beginning of the text section. In general, _stext indicates
the kernel start address. Used to convert a virtual address from the
direct kernel map to a physical address.
VMALLOC_START
-------------Annotation
- Atlas domain: Support Tooling And Documentation / Documentation.
- Implementation status: atlas-only.
- Synchronization appears in or near this file; preserve lock ordering, sleepability, and interrupt-context constraints.
Implementation Notes
- This generated page is the file-by-file coverage layer; curated subsystem chapters should link here when they synthesize a multi-file control flow.
- Core OS pages should be promoted from atlas-only to deep-reviewed when they explain data structures, invariants, locking, lifecycle, and C implementation snippets.
- Driver-family pages are intentionally pattern-oriented unless they are part of the selected PCIe/NVMe representative device path.