[PATCH v3 00/11] kdump: reduce vmcore size and capture time

[Wandun]

On 5/27/26 11:29, Wandun Chen wrote:
> From: Wandun Chen <chenwandun at lixiang.com>
>
> On SoCs that carve out large firmware-owned reserved memory (GPU
> firmware, DSP, modem, camera ISP, NPU, ...), kdump currently dumps
> those carveouts as part of system RAM even though their contents are
> firmware state that is not useful for kernel crash analysis.
>
> This series introduces an opt-in 'dumpable' flag [1] on struct
> reserved_mem and uses it to filter the elfcorehdr PT_LOAD ranges on
> DT-based architectures (arm64, riscv, loongarch). By default reserved
> regions are treated as non-dumpable; CMA regions are explicitly opted
> in because their pages are returned to the buddy allocator and may
> carry key crash-analysis data.
>
> The series is organized as follows:
> Patches 1-3: Pre-existing fixes and a small prep change.
> Patches 4-5: Restructure to allow appending /memreserve/ entries.
> Patches 6-7: Add a dumpable flag and append /memreserve/ entries.
> Patch 8: Add generic kdump helpers.
> Patches 9-11: Wire the helpers into arm64, riscv and loongarch kdump
>                elfcorehdr preparation.
Hi,

Gentle ping on this series.

Status summary:
-patch 03: respun separately per Rob's suggestion, picked up for 7.2
-patch 06: Acked-by: Marek Szyprowski -patch 09: Acked-by: Will Deacon 
The remaining patches (01, 02, 04, 05, 07, 08, 10, 11) are still 
awaiting review. your feedback would be greately appreciated. I know we 
are at the end of 7.1 -rc cycle, I don't want to rush this series, just 
collecting more feedback, and will send next version based on 7.2-rc1. 
If spliting the series into smaller logical group would make review 
easier, please let me know. Best regards, Wandun
>
> v2 --> v3:
> 1. Fix out-of-bounds issue if device tree lacks /reserved-memory node.[2]
> 2. Fix UAF issue when alloc_reserved_mem_array() fails.
> 3. Add some prepare patches.
>
> v1 --> v2:
> 1. v1 added an opt-out DT property ('linux,no-dump'). Per Rob's
>     feedback [1], v2 drop that property and exclude reserve memory
>     by default.
> 2. Split some prepared patches from the original patches.
> 3. Address coding-style comments on patch 5 from Rob.
>
> [1] https://lore.kernel.org/lkml/20260506144542.GA2072596-robh@kernel.org/
> [2] https://sashiko.dev/#/patchset/20260520091844.592753-1-chenwandun%40lixiang.com?part=4
>
> Wandun Chen (11):
>    of: reserved_mem: handle NULL name in of_reserved_mem_lookup()
>    kexec/crash: provide crash_exclude_mem_range() stub when
>      CONFIG_CRASH_DUMP=n
>    of: reserved_mem: avoid post-init UAF when alloc_reserved_mem_array()
>      fails
>    of: reserved_mem: zero total_reserved_mem_cnt if no valid
>      /reserved-memory entry
>    of: reserved_mem: split alloc_reserved_mem_array() from
>      fdt_scan_reserved_mem_late()
>    of: reserved_mem: add dumpable flag to opt-in vmcore
>    of: reserved_mem: save /memreserve/ entries into the reserved_mem
>      array
>    of: reserved_mem: add kdump helpers to exclude non-dumpable regions
>    arm64: kdump: exclude non-dumpable reserved memory regions from vmcore
>    riscv: kdump: exclude non-dumpable reserved memory regions from vmcore
>    loongarch: kdump: exclude non-dumpable reserved memory regions from
>      vmcore
>
>   arch/arm64/kernel/machine_kexec_file.c     |   6 ++
>   arch/loongarch/kernel/machine_kexec_file.c |   6 ++
>   arch/riscv/kernel/machine_kexec_file.c     |   4 +
>   drivers/of/fdt.c                           |  11 +-
>   drivers/of/of_private.h                    |   3 +
>   drivers/of/of_reserved_mem.c               | 117 +++++++++++++++++++--
>   include/linux/crash_core.h                 |   6 ++
>   include/linux/of_reserved_mem.h            |  15 +++
>   kernel/dma/contiguous.c                    |   1 +
>   9 files changed, 157 insertions(+), 12 deletions(-)
>