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From: Zhenzhong Duan <zhenzhong.duan@intel.com>
To: qemu-devel@nongnu.org
Cc: alex.williamson@redhat.com, clg@redhat.com,
	eric.auger@redhat.com, steven.sistare@oracle.com
Subject: [PATCH 5/5] accel/kvm: Fix SIGSEGV when execute "query-balloon" after CPR transfer
Date: Thu, 25 Sep 2025 22:25:40 -0400	[thread overview]
Message-ID: <20250926022540.1884023-1-zhenzhong.duan@intel.com> (raw)

After CPR transfer, source QEMU close kvm fd and free kvm_state,
"query-balloon" will check kvm_state->sync_mmu and trigger NULL
pointer reference.

Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
---
 accel/kvm/kvm-all.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c
index 9060599cd7..a3e2d11763 100644
--- a/accel/kvm/kvm-all.c
+++ b/accel/kvm/kvm-all.c
@@ -3479,7 +3479,7 @@ int kvm_device_access(int fd, int group, uint64_t attr,
 
 bool kvm_has_sync_mmu(void)
 {
-    return kvm_state->sync_mmu;
+    return kvm_state && kvm_state->sync_mmu;
 }
 
 int kvm_has_vcpu_events(void)
-- 
2.47.1



             reply	other threads:[~2025-09-26  2:27 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-09-26  2:25 Zhenzhong Duan [this message]
2025-09-26  4:48 ` [PATCH 5/5] accel/kvm: Fix SIGSEGV when execute "query-balloon" after CPR transfer Markus Armbruster
2025-09-26 13:17   ` Steven Sistare
2025-09-28  8:13   ` Duan, Zhenzhong
2025-09-29  4:32     ` Markus Armbruster
2025-09-26 13:19 ` Steven Sistare

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