[PATCH] kvm/vfio: Fix potential deadlock problem in vfio

From: Wan Jiabing
Date: Mon May 16 2022 - 22:35:06 EST


Fix following coccicheck warning:
./virt/kvm/vfio.c:258:1-7: preceding lock on line 236

If kvm_vfio_file_iommu_group() failed, code would goto err_fdput with
mutex_lock acquired and then return ret. It might cause potential
deadlock. Move mutex_unlock bellow err_fdput tag to fix it.

Fixes: d55d9e7a45721 ("kvm/vfio: Store the struct file in the kvm_vfio_group")
Signed-off-by: Wan Jiabing <wanjiabing@xxxxxxxx>
---
virt/kvm/vfio.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/virt/kvm/vfio.c b/virt/kvm/vfio.c
index 8f9f7fffb96a..ce1b01d02c51 100644
--- a/virt/kvm/vfio.c
+++ b/virt/kvm/vfio.c
@@ -252,8 +252,8 @@ static int kvm_vfio_group_set_spapr_tce(struct kvm_device *dev,
break;
}

- mutex_unlock(&kv->lock);
err_fdput:
+ mutex_unlock(&kv->lock);
fdput(f);
return ret;
}
--
2.36.1