* [PATCH] kvm/vfio: Fix potential deadlock problem in vfio
@ 2022-05-17 2:34 Wan Jiabing
2022-05-17 18:58 ` Jason Gunthorpe
2022-05-18 17:51 ` Alex Williamson
0 siblings, 2 replies; 3+ messages in thread
From: Wan Jiabing @ 2022-05-17 2:34 UTC (permalink / raw)
To: Paolo Bonzini, Alex Williamson, Yi Liu, Kevin Tian,
Jason Gunthorpe, kvm, linux-kernel
Cc: Wan Jiabing
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>
---
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
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] kvm/vfio: Fix potential deadlock problem in vfio
2022-05-17 2:34 [PATCH] kvm/vfio: Fix potential deadlock problem in vfio Wan Jiabing
@ 2022-05-17 18:58 ` Jason Gunthorpe
2022-05-18 17:51 ` Alex Williamson
1 sibling, 0 replies; 3+ messages in thread
From: Jason Gunthorpe @ 2022-05-17 18:58 UTC (permalink / raw)
To: Wan Jiabing
Cc: Paolo Bonzini, Alex Williamson, Yi Liu, Kevin Tian, kvm, linux-kernel
On Tue, May 17, 2022 at 10:34:41AM +0800, Wan Jiabing wrote:
> 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>
> ---
> virt/kvm/vfio.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Thanks,
Jason
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] kvm/vfio: Fix potential deadlock problem in vfio
2022-05-17 2:34 [PATCH] kvm/vfio: Fix potential deadlock problem in vfio Wan Jiabing
2022-05-17 18:58 ` Jason Gunthorpe
@ 2022-05-18 17:51 ` Alex Williamson
1 sibling, 0 replies; 3+ messages in thread
From: Alex Williamson @ 2022-05-18 17:51 UTC (permalink / raw)
To: Wan Jiabing
Cc: Paolo Bonzini, Yi Liu, Kevin Tian, Jason Gunthorpe, kvm, linux-kernel
On Tue, 17 May 2022 10:34:41 +0800
Wan Jiabing <wanjiabing@vivo.com> wrote:
> 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>
> ---
> 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;
> }
Applied to vfio next branch for v5.19. Thanks!
Alex
^ permalink raw reply [flat|nested] 3+ messages in thread
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2022-05-17 18:58 ` Jason Gunthorpe
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