Re: [PATCH v3 0/3] elf2dmp: identify faulting CPU in Windows crash dumps

On 2026/08/06 20:51, Zhengrong Li wrote:
> When a Windows guest crashes and QEMU generates a memory dump via
> pvpanic, elf2dmp currently always sets CPU 0's context in the dump
> header. This makes WinDbg default to CPU 0 when opening the dump,
> even if the actual crash happened on a different CPU.
> 
> This series adds crash_occurred tracking from the runstate layer
> through to the QEMUCPUState in the ELF dump, and teaches elf2dmp
> to identify and use the faulting CPU's context.
> 
> Changes since v2:
>     - Remove unused fault_cpu variable in fill_context()
>     - Use per-CPU size check (s->size >= offsetof + sizeof) instead
>       of global has_is_crash_occurred_cpu flag, fixing heterogeneous
>       dumps where CPU notes have different sizes
>     - Remove has_is_crash_occurred_cpu from QEMU_Elf struct and
>       init_states() since per-CPU check makes it unnecessary
>     - Move QEMUCPUState struct growth from patch 2 to patch 3 so
>       sizeof() change and init_states() update stay together
>       (bisectability)
>     - Fix patch 1 commit message: soften "is never called" to
>       "is not always called when crash dumping is enabled"
>     - Fix patch 2 commit message: clarify compatibility description
>       for both old-tools/new-dumps and new-tools/old-dumps directions
>     - Clamp state->size to MIN(state->size, n_descsz) in init_states()
>       to prevent reading beyond note descriptor boundary
>     - Compare state_size against offsetof + sizeof(kernel_gs_base)
>       instead of sizeof(*state) to avoid misclassifying valid old
>       440-byte notes as lacking kernel_gs_base
> 
> Changes since v1:
>     - Set header context before best-effort guest memory operations
>       to avoid losing faulting CPU context on partial dump failures
>     - Use LIVE_SYSTEM_DUMP when BugcheckCode is zero
>     - Use PRIx32 for BugcheckCode format specifier
>     - Use linux.alibaba.com identity
> 
> Zhengrong Li (3):
>    runstate: set crash_occurred on guest crashloaded
>    dump: add crash_occurred flag to QEMUCPUState
>    elf2dmp: fill ContextBuffer with faulting CPU context
> 
>   contrib/elf2dmp/kdbg.h     |  9 +++++++
>   contrib/elf2dmp/main.c     | 50 ++++++++++++++++++++++++++++++++++++--
>   contrib/elf2dmp/qemu_elf.c | 10 +++++++-
>   contrib/elf2dmp/qemu_elf.h |  2 ++
>   system/runstate.c          |  5 ++++
>   target/i386/arch_dump.c    |  6 +++++
>   6 files changed, 79 insertions(+), 3 deletions(-)
> 

The whole series now looks good to me:

Reviewed-by: Akihiko Odaki <[email protected]>

Regards,
Akihiko Odaki