From: Wan Jiabing <wanjiabing@vivo.com>
Date: Tue, 17 May 2022 02:34:41 +0000 (+0800)
Subject: kvm/vfio: Fix potential deadlock problem in vfio
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=6b17ca8e5e7a7b10689867dff5e22d7da368ba76;p=linux.git

kvm/vfio: Fix potential deadlock problem in vfio

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@vivo.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/20220517023441.4258-1-wanjiabing@vivo.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
---

diff --git a/virt/kvm/vfio.c b/virt/kvm/vfio.c
index 8f9f7fffb96a1..ce1b01d02c519 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;
 }