Update backend crash handling to a newer patch by Juergen Gross

Author: marmarek

0001-xen-xenbus-better-handle-backend-crash.patch

@@ -0,0 +1,267 @@
+From be50f0a4041116392864a9acb37315c8b8c076a7 Mon Sep 17 00:00:00 2001
+From: Juergen Gross <jgross@suse.com>
+Date: Mon, 9 Feb 2026 08:42:06 +0100
+Subject: [PATCH 1/2] xenbus: add xenbus_device parameter to
+ xenbus_read_driver_state()
+
+In order to prepare checking the xenbus device status in
+xenbus_read_driver_state(), add the pointer to struct xenbus_device
+as a parameter.
+
+Signed-off-by: Juergen Gross <jgross@suse.com>
+---
+ drivers/net/xen-netfront.c                 | 34 +++++++++++-----------
+ drivers/pci/xen-pcifront.c                 |  8 ++---
+ drivers/scsi/xen-scsifront.c               |  2 +-
+ drivers/xen/xen-pciback/xenbus.c           | 10 +++----
+ drivers/xen/xenbus/xenbus_client.c         |  3 +-
+ drivers/xen/xenbus/xenbus_probe.c          |  6 ++--
+ drivers/xen/xenbus/xenbus_probe_frontend.c |  2 +-
+ include/xen/xenbus.h                       |  3 +-
+ 8 files changed, 35 insertions(+), 33 deletions(-)
+
+diff --git a/drivers/net/xen-netfront.c b/drivers/net/xen-netfront.c
+index 7c2220366623..e2da977c9c50 100644
+--- a/drivers/net/xen-netfront.c
++++ b/drivers/net/xen-netfront.c
+@@ -1646,7 +1646,7 @@ static int xennet_xdp_set(struct net_device *dev, struct bpf_prog *prog,
+ 
+ 	/* avoid the race with XDP headroom adjustment */
+ 	wait_event(module_wq,
+-		   xenbus_read_driver_state(np->xbdev->otherend) ==
++		   xenbus_read_driver_state(np->xbdev, np->xbdev->otherend) ==
+ 		   XenbusStateReconfigured);
+ 	np->netfront_xdp_enabled = true;
+ 
+@@ -1764,9 +1764,9 @@ static struct net_device *xennet_create_dev(struct xenbus_device *dev)
+ 	do {
+ 		xenbus_switch_state(dev, XenbusStateInitialising);
+ 		err = wait_event_timeout(module_wq,
+-				 xenbus_read_driver_state(dev->otherend) !=
++				 xenbus_read_driver_state(dev, dev->otherend) !=
+ 				 XenbusStateClosed &&
+-				 xenbus_read_driver_state(dev->otherend) !=
++				 xenbus_read_driver_state(dev, dev->otherend) !=
+ 				 XenbusStateUnknown, XENNET_TIMEOUT);
+ 	} while (!err);
+ 
+@@ -2627,31 +2627,31 @@ static void xennet_bus_close(struct xenbus_device *dev)
+ {
+ 	int ret;
+ 
+-	if (xenbus_read_driver_state(dev->otherend) == XenbusStateClosed)
++	if (xenbus_read_driver_state(dev, dev->otherend) == XenbusStateClosed)
+ 		return;
+ 	do {
+ 		xenbus_switch_state(dev, XenbusStateClosing);
+ 		ret = wait_event_timeout(module_wq,
+-				   xenbus_read_driver_state(dev->otherend) ==
+-				   XenbusStateClosing ||
+-				   xenbus_read_driver_state(dev->otherend) ==
+-				   XenbusStateClosed ||
+-				   xenbus_read_driver_state(dev->otherend) ==
+-				   XenbusStateUnknown,
+-				   XENNET_TIMEOUT);
++				xenbus_read_driver_state(dev, dev->otherend) ==
++				XenbusStateClosing ||
++				xenbus_read_driver_state(dev, dev->otherend) ==
++				XenbusStateClosed ||
++				xenbus_read_driver_state(dev, dev->otherend) ==
++				XenbusStateUnknown,
++				XENNET_TIMEOUT);
+ 	} while (!ret);
+ 
+-	if (xenbus_read_driver_state(dev->otherend) == XenbusStateClosed)
++	if (xenbus_read_driver_state(dev, dev->otherend) == XenbusStateClosed)
+ 		return;
+ 
+ 	do {
+ 		xenbus_switch_state(dev, XenbusStateClosed);
+ 		ret = wait_event_timeout(module_wq,
+-				   xenbus_read_driver_state(dev->otherend) ==
+-				   XenbusStateClosed ||
+-				   xenbus_read_driver_state(dev->otherend) ==
+-				   XenbusStateUnknown,
+-				   XENNET_TIMEOUT);
++				xenbus_read_driver_state(dev, dev->otherend) ==
++				XenbusStateClosed ||
++				xenbus_read_driver_state(dev, dev->otherend) ==
++				XenbusStateUnknown,
++				XENNET_TIMEOUT);
+ 	} while (!ret);
+ }
+ 
+diff --git a/drivers/pci/xen-pcifront.c b/drivers/pci/xen-pcifront.c
+index 11636634ae51..cd22bf984024 100644
+--- a/drivers/pci/xen-pcifront.c
++++ b/drivers/pci/xen-pcifront.c
+@@ -856,7 +856,7 @@ static void pcifront_try_connect(struct pcifront_device *pdev)
+ 	int err;
+ 
+ 	/* Only connect once */
+-	if (xenbus_read_driver_state(pdev->xdev->nodename) !=
++	if (xenbus_read_driver_state(pdev->xdev, pdev->xdev->nodename) !=
+ 	    XenbusStateInitialised)
+ 		return;
+ 
+@@ -876,7 +876,7 @@ static int pcifront_try_disconnect(struct pcifront_device *pdev)
+ 	enum xenbus_state prev_state;
+ 
+ 
+-	prev_state = xenbus_read_driver_state(pdev->xdev->nodename);
++	prev_state = xenbus_read_driver_state(pdev->xdev, pdev->xdev->nodename);
+ 
+ 	if (prev_state >= XenbusStateClosing)
+ 		goto out;
+@@ -895,7 +895,7 @@ static int pcifront_try_disconnect(struct pcifront_device *pdev)
+ 
+ static void pcifront_attach_devices(struct pcifront_device *pdev)
+ {
+-	if (xenbus_read_driver_state(pdev->xdev->nodename) ==
++	if (xenbus_read_driver_state(pdev->xdev, pdev->xdev->nodename) ==
+ 	    XenbusStateReconfiguring)
+ 		pcifront_connect(pdev);
+ }
+@@ -909,7 +909,7 @@ static int pcifront_detach_devices(struct pcifront_device *pdev)
+ 	struct pci_dev *pci_dev;
+ 	char str[64];
+ 
+-	state = xenbus_read_driver_state(pdev->xdev->nodename);
++	state = xenbus_read_driver_state(pdev->xdev, pdev->xdev->nodename);
+ 	if (state == XenbusStateInitialised) {
+ 		dev_dbg(&pdev->xdev->dev, "Handle skipped connect.\n");
+ 		/* We missed Connected and need to initialize. */
+diff --git a/drivers/scsi/xen-scsifront.c b/drivers/scsi/xen-scsifront.c
+index 924025305753..ef74d4da5ab0 100644
+--- a/drivers/scsi/xen-scsifront.c
++++ b/drivers/scsi/xen-scsifront.c
+@@ -1175,7 +1175,7 @@ static void scsifront_backend_changed(struct xenbus_device *dev,
+ 			return;
+ 		}
+ 
+-		if (xenbus_read_driver_state(dev->nodename) ==
++		if (xenbus_read_driver_state(dev, dev->nodename) ==
+ 		    XenbusStateInitialised)
+ 			scsifront_do_lun_hotplug(info, VSCSIFRONT_OP_ADD_LUN);
+ 
+diff --git a/drivers/xen/xen-pciback/xenbus.c b/drivers/xen/xen-pciback/xenbus.c
+index b11e401f1b1e..4bd1c7a8957e 100644
+--- a/drivers/xen/xen-pciback/xenbus.c
++++ b/drivers/xen/xen-pciback/xenbus.c
+@@ -149,12 +149,12 @@ static int xen_pcibk_attach(struct xen_pcibk_device *pdev)
+ 
+ 	mutex_lock(&pdev->dev_lock);
+ 	/* Make sure we only do this setup once */
+-	if (xenbus_read_driver_state(pdev->xdev->nodename) !=
++	if (xenbus_read_driver_state(pdev->xdev, pdev->xdev->nodename) !=
+ 	    XenbusStateInitialised)
+ 		goto out;
+ 
+ 	/* Wait for frontend to state that it has published the configuration */
+-	if (xenbus_read_driver_state(pdev->xdev->otherend) !=
++	if (xenbus_read_driver_state(pdev->xdev, pdev->xdev->otherend) !=
+ 	    XenbusStateInitialised)
+ 		goto out;
+ 
+@@ -374,7 +374,7 @@ static int xen_pcibk_reconfigure(struct xen_pcibk_device *pdev,
+ 	dev_dbg(&pdev->xdev->dev, "Reconfiguring device ...\n");
+ 
+ 	mutex_lock(&pdev->dev_lock);
+-	if (xenbus_read_driver_state(pdev->xdev->nodename) != state)
++	if (xenbus_read_driver_state(pdev->xdev, pdev->xdev->nodename) != state)
+ 		goto out;
+ 
+ 	err = xenbus_scanf(XBT_NIL, pdev->xdev->nodename, "num_devs", "%d",
+@@ -572,7 +572,7 @@ static int xen_pcibk_setup_backend(struct xen_pcibk_device *pdev)
+ 	/* It's possible we could get the call to setup twice, so make sure
+ 	 * we're not already connected.
+ 	 */
+-	if (xenbus_read_driver_state(pdev->xdev->nodename) !=
++	if (xenbus_read_driver_state(pdev->xdev, pdev->xdev->nodename) !=
+ 	    XenbusStateInitWait)
+ 		goto out;
+ 
+@@ -662,7 +662,7 @@ static void xen_pcibk_be_watch(struct xenbus_watch *watch,
+ 	struct xen_pcibk_device *pdev =
+ 	    container_of(watch, struct xen_pcibk_device, be_watch);
+ 
+-	switch (xenbus_read_driver_state(pdev->xdev->nodename)) {
++	switch (xenbus_read_driver_state(pdev->xdev, pdev->xdev->nodename)) {
+ 	case XenbusStateInitWait:
+ 		xen_pcibk_setup_backend(pdev);
+ 		break;
+diff --git a/drivers/xen/xenbus/xenbus_client.c b/drivers/xen/xenbus/xenbus_client.c
+index 2dc874fb5506..6ed0cd8e9676 100644
+--- a/drivers/xen/xenbus/xenbus_client.c
++++ b/drivers/xen/xenbus/xenbus_client.c
+@@ -936,7 +936,8 @@ static int xenbus_unmap_ring_hvm(struct xenbus_device *dev, void *vaddr)
+  * Returns: the state of the driver rooted at the given store path, or
+  * XenbusStateUnknown if no state can be read.
+  */
+-enum xenbus_state xenbus_read_driver_state(const char *path)
++enum xenbus_state xenbus_read_driver_state(const struct xenbus_device *dev,
++					   const char *path)
+ {
+ 	enum xenbus_state result;
+ 	int err = xenbus_gather(XBT_NIL, path, "state", "%d", &result, NULL);
+diff --git a/drivers/xen/xenbus/xenbus_probe.c b/drivers/xen/xenbus/xenbus_probe.c
+index 86fe6e779056..d4f1dbf7cbc4 100644
+--- a/drivers/xen/xenbus/xenbus_probe.c
++++ b/drivers/xen/xenbus/xenbus_probe.c
+@@ -191,7 +191,7 @@ void xenbus_otherend_changed(struct xenbus_watch *watch,
+ 		return;
+ 	}
+ 
+-	state = xenbus_read_driver_state(dev->otherend);
++	state = xenbus_read_driver_state(dev, dev->otherend);
+ 
+ 	dev_dbg(&dev->dev, "state is %d, (%s), %s, %s\n",
+ 		state, xenbus_strstate(state), dev->otherend_watch.node, path);
+@@ -364,7 +364,7 @@ void xenbus_dev_remove(struct device *_dev)
+ 	 * closed.
+ 	 */
+ 	if (!drv->allow_rebind ||
+-	    xenbus_read_driver_state(dev->nodename) == XenbusStateClosing)
++	    xenbus_read_driver_state(dev, dev->nodename) == XenbusStateClosing)
+ 		xenbus_switch_state(dev, XenbusStateClosed);
+ }
+ EXPORT_SYMBOL_GPL(xenbus_dev_remove);
+@@ -514,7 +514,7 @@ int xenbus_probe_node(struct xen_bus_type *bus,
+ 	size_t stringlen;
+ 	char *tmpstring;
+ 
+-	enum xenbus_state state = xenbus_read_driver_state(nodename);
++	enum xenbus_state state = xenbus_read_driver_state(NULL, nodename);
+ 
+ 	if (state != XenbusStateInitialising) {
+ 		/* Device is not new, so ignore it.  This can happen if a
+diff --git a/drivers/xen/xenbus/xenbus_probe_frontend.c b/drivers/xen/xenbus/xenbus_probe_frontend.c
+index 6d1819269cbe..41832994f8b1 100644
+--- a/drivers/xen/xenbus/xenbus_probe_frontend.c
++++ b/drivers/xen/xenbus/xenbus_probe_frontend.c
+@@ -255,7 +255,7 @@ static int print_device_status(struct device *dev, void *data)
+ 	} else if (xendev->state < XenbusStateConnected) {
+ 		enum xenbus_state rstate = XenbusStateUnknown;
+ 		if (xendev->otherend)
+-			rstate = xenbus_read_driver_state(xendev->otherend);
++			rstate = xenbus_read_driver_state(xendev, xendev->otherend);
+ 		pr_warn("Timeout connecting to device: %s (local state %d, remote state %d)\n",
+ 			xendev->nodename, xendev->state, rstate);
+ 	}
+diff --git a/include/xen/xenbus.h b/include/xen/xenbus.h
+index c94caf852aea..15319da65b7f 100644
+--- a/include/xen/xenbus.h
++++ b/include/xen/xenbus.h
+@@ -228,7 +228,8 @@ int xenbus_unmap_ring_vfree(struct xenbus_device *dev, void *vaddr);
+ int xenbus_alloc_evtchn(struct xenbus_device *dev, evtchn_port_t *port);
+ int xenbus_free_evtchn(struct xenbus_device *dev, evtchn_port_t port);
+ 
+-enum xenbus_state xenbus_read_driver_state(const char *path);
++enum xenbus_state xenbus_read_driver_state(const struct xenbus_device *dev,
++					   const char *path);
+ 
+ __printf(3, 4)
+ void xenbus_dev_error(struct xenbus_device *dev, int err, const char *fmt, ...);
+-- 
+2.53.0
+