| What: /sys/kernel/kexec/* | |
| Date: Nov 2025 | |
| Contact: kexec@lists.infradead.org | |
| Description: | |
| The /sys/kernel/kexec/* directory contains sysfs files | |
| that provide information about the configuration status | |
| of kexec and kdump. | |
| What: /sys/kernel/kexec/loaded | |
| Date: Nov 2025 | |
| Contact: kexec@lists.infradead.org | |
| Description: read only | |
| Indicates whether a new kernel image has been loaded | |
| into memory using the kexec system call. It shows 1 if | |
| a kexec image is present and ready to boot, or 0 if none | |
| is loaded. | |
| User: kexec tools, kdump service | |
| What: /sys/kernel/kexec/crash_loaded | |
| Date: Nov 2025 | |
| Contact: kexec@lists.infradead.org | |
| Description: read only | |
| Indicates whether a crash (kdump) kernel is currently | |
| loaded into memory. It shows 1 if a crash kernel has been | |
| successfully loaded for panic handling, or 0 if no crash | |
| kernel is present. | |
| User: Kexec tools, Kdump service | |
| What: /sys/kernel/kexec/crash_size | |
| Date: Nov 2025 | |
| Contact: kexec@lists.infradead.org | |
| Description: read/write | |
| Shows the amount of memory reserved for loading the crash | |
| (kdump) kernel. It reports the size, in bytes, of the | |
| crash kernel area defined by the crashkernel= parameter. | |
| This interface also allows reducing the crashkernel | |
| reservation by writing a smaller value, and the reclaimed | |
| space is added back to the system RAM. | |
| User: Kdump service | |
| What: /sys/kernel/kexec/crash_elfcorehdr_size | |
| Date: Nov 2025 | |
| Contact: kexec@lists.infradead.org | |
| Description: read only | |
| Indicates the preferred size of the memory buffer for the | |
| ELF core header used by the crash (kdump) kernel. It defines | |
| how much space is needed to hold metadata about the crashed | |
| system, including CPU and memory information. This information | |
| is used by the user space utility kexec to support updating the | |
| in-kernel kdump image during hotplug operations. | |
| User: Kexec tools | |
| What: /sys/kernel/kexec/crash_cma_ranges | |
| Date: Nov 2025 | |
| Contact: kexec@lists.infradead.org | |
| Description: read only | |
| Provides information about the memory ranges reserved from | |
| the Contiguous Memory Allocator (CMA) area that are allocated | |
| to the crash (kdump) kernel. It lists the start and end physical | |
| addresses of CMA regions assigned for crashkernel use. | |
| User: kdump service |