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