Re: [PATCH v2 0/5] arm64: crash: Add crash hotplug support

[Jinjie Ruan <ruanjinjie@huawei.com>]

在 2026/7/29 11:12, Jinjie Ruan 写道:
> When CPU or memory hotplug events occur, the elfcorehdr in the kdump
> image becomes stale, potentially leading to incomplete crash dumps.
> 
> Currently, userspace udev rules reload the entire kdump image upon such
> events, which is inefficient and leaves kdump inactive for a long time.
> 
> Commit 247262756121 ("crash: add generic infrastructure for crash hotplug
> support") introduced a kernel mechanism to update only the elfcorehdr.
> This patch set implements crash hotplug support for arm64.
> 
> As Baoquan suggested, it also addresses and fixes several
> pre-existing code issues and Sashiko AI review findings extracted
> from the previous patch set.
> 
> The major improvements and fixes included in this series are:
> - Fix several memory leaks for arm64.
> - Simplify arm64 load_other_segments().
> - Implement infrastructure for arm64 crash memory hotplug support.

Hi all,

I'd like to ask if anyone has any suggestions for improvement?

> 
> This patch set is rebased on liveupdate/crashkernel-cma.
> 
> Link: https://lore.kernel.org/all/20260601094805.2928614-1-ruanjinjie@huawei.com/
> 
> Changes in v2:
> - Split out Powerpc bugfix patch as Mike suggested.
> - Use phys_to_virt() instead of __va() in update_crash_elfcorehdr().
> - Convert pnum_hdr_sz() to a function.
> - Only assign elfcorehdr_index after kexec_add_buffer succeeds, considering
>   crash_handle_hotplug_event() already performs validity check on
>   elfcorehdr_index:
>   - We can safely remove the check for CPU hotplug
>     in arch_crash_handle_hotplug_event().
>   - The elfcorehdr_index's segment mem will be valid in
>     update_crash_elfcorehdr(), so we can safely remove the NULL check.
> - Simplify the commit message.
> - v1: https://lore.kernel.org/all/20260723131242.1537633-1-ruanjinjie@huawei.com/#t
> 
> Jinjie Ruan (5):
>   kexec: Extract kexec_free_segment_cma() from kimage_free_cma()
>   arm64: kexec_file: Fix CMA page leaks in segment placement retry loops
>   arm64: kexec_file: Fix image->elf_headers memory leak in retry loop
>   arm64: kexec_file: Simplify load_other_segments()
>   arm64: crash: Add crash hotplug support
> 
>  arch/arm64/Kconfig                     |   3 +
>  arch/arm64/include/asm/kexec.h         |  16 +++
>  arch/arm64/kernel/Makefile             |   2 +-
>  arch/arm64/kernel/crash.c              | 143 +++++++++++++++++++++++++
>  arch/arm64/kernel/kexec_image.c        |   1 +
>  arch/arm64/kernel/machine_kexec_file.c |  78 +++++++-------
>  include/linux/kexec.h                  |   2 +
>  kernel/kexec_core.c                    |  25 +++--
>  8 files changed, 216 insertions(+), 54 deletions(-)
>  create mode 100644 arch/arm64/kernel/crash.c
>