This series extends vmcoreinfo with struct offsets and sizes needed by the vmcore-tasks userspace tool to extract per-task state from a vmcore dump without requiring kernel debug symbols (DWARF/BTF).
The vmcore-tasks tool reads /proc/vmcore (or a saved vmcore file) and reconstructs, for each task: - task name, pid, state, flags - VMA list (start, end, flags, backing file) - user register state (saved on the kernel stack at kernel entry) - user-space backtrace with VMA/filename mapping - kernel dmesg buffer This provides a lightweight post-mortem crash analysis capability for production environments where full debug info (DWARF/BTF) is not available. The companion userspace tool is submitted to kexec-tools: https://lore.kernel.org/all/[email protected]/ The series is structured as follows: Patch 1: Increase vmcoreinfo buffer from PAGE_SIZE to a fixed SZ_8K, decoupled from page size to avoid waste on large-page architectures (MIPS 16KB, arm64 64KB). Patch 2: Export generic struct offsets (task_struct, mm_struct, vm_area_struct, maple_tree, file/dentry/path, pt_regs, signal_struct) needed to walk task lists and VMAs. Patch 3: Export RISC-V arch-specific offsets (signal frame layouts, register context structures) for user register extraction. Patch 4: Export MIPS arch-specific offsets (signal frame layouts, register context structures) for user register extraction. Additional architecture support (arm64, x86, etc.) can follow the same pattern established by patches 3 and 4. Tested on MIPS64 (QEMU Malta) and RISC-V with full kdump pipeline: primary kernel -> kexec panic -> crash kernel -> vmcore-tasks analysis. Pnina Feder (4): vmcoreinfo: increase vmcoreinfo buffer to 8KB vmcoreinfo: export task and mm struct offsets to vmcoreinfo riscv: vmcore_info: export riscv arch-specific struct offsets to vmcoreinfo mips: vmcore_info: export mips arch-specific struct offsets to vmcoreinfo .../admin-guide/kdump/vmcoreinfo.rst | 137 ++++++++++++++++++ arch/mips/kernel/Makefile | 1 + arch/mips/kernel/signal.c | 8 + arch/mips/kernel/vmcore_info.c | 22 +++ arch/riscv/kernel/signal.c | 8 + arch/riscv/kernel/vmcore_info.c | 11 ++ include/linux/vmcore_info.h | 3 +- kernel/vmcore_info.c | 60 ++++++++ 8 files changed, 249 insertions(+), 1 deletion(-) create mode 100644 arch/mips/kernel/vmcore_info.c -- 2.43.0
