CONFIG_CRASH_MAX_MEMORY_RANGES: Specify the maximum number of memory regions for the elfcorehdr

General informations

The Linux kernel configuration item CONFIG_CRASH_MAX_MEMORY_RANGES:

• prompt: Specify the maximum number of memory regions for the elfcorehdr
• type: int
• depends on: CONFIG_CRASH_HOTPLUG
• defined in kernel/Kconfig.kexec
• found in Linux kernels: 6.6–6.8, 6.9-rc+HEAD

Help text

For the kexec_file_load() syscall path, specify the maximum number of memory regions that the elfcorehdr buffer/segment can accommodate. These regions are obtained via walk_system_ram_res(); eg. the 'System RAM' entries in /proc/iomem. This value is combined with NR_CPUS_DEFAULT and multiplied by sizeof(Elf64_Phdr) to determine the final elfcorehdr memory buffer/ segment size. The value 8192, for example, covers a (sparsely populated) 1TiB system consisting of 128MiB memblocks, while resulting in an elfcorehdr memory buffer/segment size under 1MiB. This represents a sane choice to accommodate both baremetal and virtual machine configurations.

For the kexec_load() syscall path, CRASH_MAX_MEMORY_RANGES is part of the computation behind the value provided through the /sys/kernel/crash_elfcorehdr_size attribute.

Hardware

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This page is automaticly generated with free (libre, open) software lkddb(see lkddb-sources).

The data is retrived from:

• Linux kernel
• Linux Kernel Driver DataBase (LKDDb)

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