chore: add 9p disconnection fix, sent upstream

config.yaml

@@ -74,6 +74,8 @@ patches:
   - zone-amdgpu
 - patch: 0001-x86-CPU-AMD-avoid-printing-reset-reasons-on-Xen-domU.patch
   lower: '6.16'
+- patch: 0001-9p-xen-mark-9p-transport-device-as-closing-when-remo.patch
+  lower: '6.1'
 images:
 - target: kernelsrc
   name: kernel-src

patches/0001-9p-xen-mark-9p-transport-device-as-closing-when-remo.patch

@@ -0,0 +1,35 @@
+From 8e7d925b756b09c7c52b1b06a3c3c996d9127d64 Mon Sep 17 00:00:00 2001
+From: Ariadne Conill <[email protected]>
+Date: Mon, 8 Dec 2025 11:40:56 -0800
+Subject: [PATCH] 9p/xen: mark 9p transport device as closing when removing it
+
+We need to do this so that we can signal to the other end that the
+device is being removed, so that it will release its claim on the
+underlying memory allocation.  Otherwise releasing the grant-table
+entries is deferred resulting in a kernel oops since the pages have
+already been freed.
+
+Cc: Juergen Gross <[email protected]>
+Cc: Stefano Stabellini <[email protected]>
+Fixes: 71ebd71921e45 ("xen/9pfs: connect to the backend")
+Signed-off-by: Ariadne Conill <[email protected]>
+Signed-off-by: Alex Zenla <[email protected]>
+---
+ net/9p/trans_xen.c | 1 +
+ 1 file changed, 1 insertion(+)
+
+diff --git a/net/9p/trans_xen.c b/net/9p/trans_xen.c
+index b9ff69c7522a..cde283c42dc6 100644
+--- a/net/9p/trans_xen.c
++++ b/net/9p/trans_xen.c
+@@ -312,6 +312,7 @@ static void xen_9pfs_front_remove(struct xenbus_device *dev)
+ {
+ 	struct xen_9pfs_front_priv *priv = dev_get_drvdata(&dev->dev);
+
++	xenbus_switch_state(dev, XenbusStateClosing);
+ 	dev_set_drvdata(&dev->dev, NULL);
+ 	xen_9pfs_front_free(priv);
+ }
+-- 
+2.52.0
+