On 07/31/24 at 08:57pm, Sourabh Jain wrote:
> 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.
>
> During kexec, the offline CPUs are brought online, which triggers the
Is this a generic action or specific on ppc about the offline CPUs being
brought line during kexec?
> crash hotplug handler `crash_handle_hotplug_event()` to update the kdump
> image. Given that the system is on the kexec path and the kexec lock is
> taken, the `crash_handle_hotplug_event()` function fails to take the
> same lock to update the kdump image, resulting in the above error
> messages.
>
> To fix this, let's return from `crash_handle_hotplug_event()` if kexec
> is in progress.
>
> The same applies to the `crash_check_hotplug_support()` function.
> Return 0 if kexec is in progress.
>
> Cc: Hari Bathini <hbathini@xxxxxxxxxxxxx>
> Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
> Cc: kexec@xxxxxxxxxxxxxxxxxxx
> Cc: linuxppc-dev@xxxxxxxxxx
> Cc: linux-kernel@xxxxxxxxxxxxxxx
> Cc: x86@xxxxxxxxxx
> Reported-by: Sachin P Bappalige <sachinpb@xxxxxxxxxxxxxxxxxx>
> Signed-off-by: Sourabh Jain <sourabhjain@xxxxxxxxxxxxx>
> ---
> kernel/crash_core.c | 6 ++++++
> 1 file changed, 6 insertions(+)
>
> diff --git a/kernel/crash_core.c b/kernel/crash_core.c
> index 63cf89393c6e..d37a16d5c3a1 100644
> --- a/kernel/crash_core.c
> +++ b/kernel/crash_core.c
> @@ -502,6 +502,9 @@ int crash_check_hotplug_support(void)
> {
> int rc = 0;
>
> + if (kexec_in_progress)
> + return 0;
> +
> crash_hotplug_lock();
> /* Obtain lock while reading crash information */
> if (!kexec_trylock()) {
> @@ -537,6 +540,9 @@ static void crash_handle_hotplug_event(unsigned int hp_action, unsigned int cpu,
> {
> struct kimage *image;
>
> + if (kexec_in_progress)
> + return;
> +
> crash_hotplug_lock();
> /* Obtain lock while changing crash information */
> if (!kexec_trylock()) {
> --
> 2.45.2
>
>
> _______________________________________________
> kexec mailing list
> kexec@xxxxxxxxxxxxxxxxxxx
> http://lists.infradead.org/mailman/listinfo/kexec
>
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