From cf4a4493ff70874f8af26d75d4346c591c298e89 Mon Sep 17 00:00:00 2001
From: Peng Hao <flyingpenghao@gmail.com>
Date: Wed, 22 Dec 2021 09:12:25 +0800
Subject: [PATCH] virtio/virtio_mem: handle a possible NULL as a memcpy parameter
Git-commit: cf4a4493ff70874f8af26d75d4346c591c298e89
Patch-mainline: v5.17-rc1
References: git-fixes
There is a check for vm->sbm.sb_states before, and it should check
it here as well.
Signed-off-by: Peng Hao <flyingpeng@tencent.com>
Link: https://lore.kernel.org/r/20211222011225.40573-1-flyingpeng@tencent.com
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Fixes: 5f1f79bbc9e2 ("virtio-mem: Paravirtualized memory hotplug")
Cc: stable@vger.kernel.org # v5.8+
Acked-by: Takashi Iwai <tiwai@suse.de>
---
drivers/virtio/virtio_mem.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/virtio/virtio_mem.c b/drivers/virtio/virtio_mem.c
index a6a78685cfbe..38becd8d578c 100644
--- a/drivers/virtio/virtio_mem.c
+++ b/drivers/virtio/virtio_mem.c
@@ -593,7 +593,7 @@ static int virtio_mem_sbm_sb_states_prepare_next_mb(struct virtio_mem *vm)
return -ENOMEM;
mutex_lock(&vm->hotplug_mutex);
- if (new_bitmap)
+ if (vm->sbm.sb_states)
memcpy(new_bitmap, vm->sbm.sb_states, old_pages * PAGE_SIZE);
old_bitmap = vm->sbm.sb_states;
--
2.31.1