Re: [PATCH v4 2/3] mshv: clean up SynIC state on kexec for L1VH

Stanislav Kinsburskii
2026-04-28T23:28:28Z

On Mon, Apr 27, 2026 at 02:38:53PM -0700, Jork Loeser wrote:
> The reboot notifier that tears down the SynIC cpuhp state guards the
> cleanup with hv_root_partition(), so on L1VH (where
> hv_root_partition() is false) SINT0, SINT5, and SIRBP are never
> cleaned up before kexec. The kexec'd kernel then inherits stale
> unmasked SINTs and an enabled SIRBP pointing to freed memory.
>
> Remove the hv_root_partition() guard so the cleanup runs for all
> parent partitions.
>
> Signed-off-by: Jork Loeser <jloeser@linux.microsoft.com>

Reviewed-by: Stanislav Kinsburskii <skinsburskii@linux.microsoft.com>

> ---
> drivers/hv/mshv_synic.c | 3 ---
> 1 file changed, 3 deletions(-)
>
> diff --git a/drivers/hv/mshv_synic.c b/drivers/hv/mshv_synic.c
> index 2db3b0192eac..978a1cace341 100644
> --- a/drivers/hv/mshv_synic.c
> +++ b/drivers/hv/mshv_synic.c
> @@ -723,9 +723,6 @@ mshv_unregister_doorbell(u64 partition_id, int doorbell_portid)
> static int mshv_synic_reboot_notify(struct notifier_block *nb,
> unsigned long code, void *unused)
> {
> - if (!hv_root_partition())
> - return 0;
> -
> cpuhp_remove_state(synic_cpuhp_online);
> return 0;
> }
> --
> 2.43.0
>