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Fix hang on netfront removal

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Fixes QubesOS/qubes-issues#3657
This commit is contained in:
Simon Gaiser 2018-04-19 17:02:17 +02:00
parent a790a45b7b
commit 0965ff2bef
2 changed files with 56 additions and 0 deletions
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53
patches.xen/c2d2e6738a20-xen-netfront-Fix-hang-on-device-removal.patch Normal file
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@ -0,0 +1,53 @@
From c2d2e6738a209f0f9dffa2dc8e7292fc45360d61 Mon Sep 17 00:00:00 2001
From: Jason Andryuk <jandryuk@gmail.com>
Date: Wed, 28 Feb 2018 07:23:23 -0500
Subject: [PATCH] xen-netfront: Fix hang on device removal
A toolstack may delete the vif frontend and backend xenstore entries
while xen-netfront is in the removal code path. In that case, the
checks for xenbus_read_driver_state would return XenbusStateUnknown, and
xennet_remove would hang indefinitely. This hang prevents system
shutdown.
xennet_remove must be able to handle XenbusStateUnknown, and
netback_changed must also wake up the wake_queue for that state as well.
Fixes: 5b5971df3bc2 ("xen-netfront: remove warning when unloading module")
Signed-off-by: Jason Andryuk <jandryuk@gmail.com>
Cc: Eduardo Otubo <otubo@redhat.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
---
drivers/net/xen-netfront.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/drivers/net/xen-netfront.c b/drivers/net/xen-netfront.c
index 8328d395e332..3127bc8633ca 100644
--- a/drivers/net/xen-netfront.c
+++ b/drivers/net/xen-netfront.c
@@ -2005,7 +2005,10 @@ static void netback_changed(struct xenbus_device *dev,
case XenbusStateInitialised:
case XenbusStateReconfiguring:
case XenbusStateReconfigured:
+ break;
+
case XenbusStateUnknown:
+ wake_up_all(&module_unload_q);
break;
case XenbusStateInitWait:
@@ -2136,7 +2139,9 @@ static int xennet_remove(struct xenbus_device *dev)
xenbus_switch_state(dev, XenbusStateClosing);
wait_event(module_unload_q,
xenbus_read_driver_state(dev->otherend) ==
- XenbusStateClosing);
+ XenbusStateClosing ||
+ xenbus_read_driver_state(dev->otherend) ==
+ XenbusStateUnknown);
xenbus_switch_state(dev, XenbusStateClosed);
wait_event(module_unload_q,
--
2.17.0

3
series.conf
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@ -30,6 +30,9 @@ patches.xen/2a22ee6c3ab1-xen-xenbus_dev_frontend-Fix-XS_TRANSACTION_END-handl.pa
patches.xen/b93008d1ac65-xen-xenbus-Catch-closing-of-non-existent-transaction.patch
patches.xen/8fe5ab411209-xen-xenbus_dev_frontend-Verify-body-of-XS_TRANSACTIO.patch
# Fix for hang on netfront removal
patches.xen/c2d2e6738a20-xen-netfront-Fix-hang-on-device-removal.patch
# Hardware-specific fixes, backported from newer kernel and/or developers branches
patches.backports/v2-2-2-Input-synaptics---Lenovo-X1-Carbon-5-should-use-SMBUS-RMI.patch
patches.backports/Input-synaptics---add-Intertouch-support-on-X1-Carbon-6th-and-X280.patch