> -----Original Message-----
> From: Tianyu Lan <[email protected]>
> Sent: Tuesday, February 1, 2022 11:32 AM
> To: KY Srinivasan <[email protected]>; Haiyang Zhang 
> <[email protected]>; Stephen
> Hemminger <[email protected]>; [email protected]; Dexuan Cui 
> <[email protected]>;
> [email protected]; [email protected]; [email protected]; 
> [email protected];
> [email protected]; [email protected]; [email protected]; [email protected]; 
> [email protected];
> [email protected]; [email protected]; Michael Kelley (LINUX)
> <[email protected]>
> Cc: Tianyu Lan <[email protected]>; [email protected]; 
> linux-
> [email protected]; [email protected]; [email protected]
> Subject: [PATCH] Netvsc: Call hv_unmap_memory() in the netvsc_device_remove()
> 
> From: Tianyu Lan <[email protected]>
> 
> netvsc_device_remove() calls vunmap() inside which should not be
> called in the interrupt context. Current code calls hv_unmap_memory()
> in the free_netvsc_device() which is rcu callback and maybe called
> in the interrupt context. This will trigger BUG_ON(in_interrupt())
> in the vunmap(). Fix it via moving hv_unmap_memory() to netvsc_device_
> remove().
> 
> Fixes: 846da38de0e8 ("net: netvsc: Add Isolation VM support for netvsc 
> driver")
> Signed-off-by: Tianyu Lan <[email protected]>
> ---
>  drivers/net/hyperv/netvsc.c | 18 ++++++++++--------
>  1 file changed, 10 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/net/hyperv/netvsc.c b/drivers/net/hyperv/netvsc.c
> index afa81a9480cc..f989f920d4ce 100644
> --- a/drivers/net/hyperv/netvsc.c
> +++ b/drivers/net/hyperv/netvsc.c
> @@ -154,19 +154,15 @@ static void free_netvsc_device(struct rcu_head *head)
> 
>       kfree(nvdev->extension);
> 
> -     if (nvdev->recv_original_buf) {
> -             hv_unmap_memory(nvdev->recv_buf);
> +     if (nvdev->recv_original_buf)
>               vfree(nvdev->recv_original_buf);
> -     } else {
> +     else
>               vfree(nvdev->recv_buf);
> -     }
> 
> -     if (nvdev->send_original_buf) {
> -             hv_unmap_memory(nvdev->send_buf);
> +     if (nvdev->send_original_buf)
>               vfree(nvdev->send_original_buf);
> -     } else {
> +     else
>               vfree(nvdev->send_buf);
> -     }
> 
>       bitmap_free(nvdev->send_section_map);
> 
> @@ -765,6 +761,12 @@ void netvsc_device_remove(struct hv_device *device)
>               netvsc_teardown_send_gpadl(device, net_device, ndev);
>       }
> 
> +     if (net_device->recv_original_buf)
> +             hv_unmap_memory(net_device->recv_buf);
> +
> +     if (net_device->send_original_buf)
> +             hv_unmap_memory(net_device->send_buf);
> +
>       /* Release all resources */
>       free_netvsc_device_rcu(net_device);
>  }

Reviewed-by: Haiyang Zhang <[email protected]>
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