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charset="utf-8" Add a sysfs entry /sys/kernel/kexec/crash_cma_ranges to expose all CMA crashkernel ranges. This allows userspace tools configuring kdump to determine how much memory is reserved for crashkernel. If CMA is used, tools can warn users when attempting to capture user pages with CMA reservation. The new sysfs hold the CMA ranges in below format: cat /sys/kernel/kexec/crash_cma_ranges 100000000-10c7fffff Cc: Aditya Gupta Cc: Andrew Morton Cc: Baoquan he Cc: Dave Young Cc: Hari Bathini Cc: Jiri Bohac Cc: Madhavan Srinivasan Cc: Mahesh J Salgaonkar Cc: Pingfan Liu Cc: Ritesh Harjani (IBM) Cc: Shivang Upadhyay Cc: Vivek Goyal Cc: linuxppc-dev@lists.ozlabs.org Cc: kexec@lists.infradead.org Signed-off-by: Sourabh Jain --- Documentation/ABI/testing/sysfs-kernel-kexec-kdump | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/Documentation/ABI/testing/sysfs-kernel-kexec-kdump b/Documenta= tion/ABI/testing/sysfs-kernel-kexec-kdump index 00c00f380fea..f59051b5d96d 100644 --- a/Documentation/ABI/testing/sysfs-kernel-kexec-kdump +++ b/Documentation/ABI/testing/sysfs-kernel-kexec-kdump @@ -49,3 +49,13 @@ Description: read only 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 --=20 2.51.0