Hello Baoquan,

On 11/09/24 19:50, Baoquan He wrote:

On 09/11/24 at 04:51pm, Sourabh Jain wrote:

quoted

The following errors are observed when kexec is done with SMT=off on
powerpc.

[  358.458385] Removing IBM Power 842 compression device
[  374.795734] kexec_core: Starting new kernel
[  374.795748] kexec: Waking offline cpu 1.
[  374.875695] crash hp: kexec_trylock() failed, elfcorehdr may be inaccurate
[  374.935833] kexec: Waking offline cpu 2.
[  375.015664] crash hp: kexec_trylock() failed, elfcorehdr may be inaccurate
snip..
[  375.515823] kexec: Waking offline cpu 6.
[  375.635667] crash hp: kexec_trylock() failed, elfcorehdr may be inaccurate
[  375.695836] kexec: Waking offline cpu 7.

To avoid kexec kernel boot failure on PowerPC, all the present CPUs that
are offline are brought online during kexec. For more information, refer
to commit e8e5c2155b00 ("powerpc/kexec: Fix orphaned offline CPUs across
kexec"). Bringing the CPUs online triggers the crash hotplug handler,
crash_handle_hotplug_event(), to update the kdump image. Since the
system is on the kexec kernel boot path and the kexec lock is held, the
crash_handle_hotplug_event() function fails to acquire the same lock to
update the kdump image, resulting in the error messages mentioned above.

To fix this, return from crash_handle_hotplug_event() without printing
the error message if kexec is in progress.

The same applies to the crash_check_hotplug_support() function. Return
0 if kexec is in progress because kernel is not in a position to update
the kdump image.

LGTM, thanks.

Acked-by: Baoquan he <redacted>

Thank you for the Ack!

My understanding is that this patch will go upstream via the linux-next 
tree, as it is based on 
https://lore.kernel.org/all/20240902034708.88EC1C4CEC2@smtp.kernel.org/ (local) 
which is already part of the linux-next master branch. - Sourabh Jain