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

Jork Loeser
2026-04-27T21:39:06Z

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>
---
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