This is a note to let you know that I've just added the patch titled
xen/gntdevt: Fix race condition in gntdev_release()
to the 3.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
xen-gntdevt-fix-race-condition-in-gntdev_release.patch
and it can be found in the queue-3.14 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 30b03d05e07467b8c6ec683ea96b5bffcbcd3931 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Marek=20Marczykowski-G=C3=B3recki?=
<marmarek@xxxxxxxxxxxxxxxxxxxxxx>
Date: Fri, 26 Jun 2015 03:28:24 +0200
Subject: xen/gntdevt: Fix race condition in gntdev_release()
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From: =?UTF-8?q?Marek=20Marczykowski-G=C3=B3recki?=
commit 30b03d05e07467b8c6ec683ea96b5bffcbcd3931 upstream.
While gntdev_release() is called the MMU notifier is still registered
and can traverse priv->maps list even if no pages are mapped (which is
the case -- gntdev_release() is called after all). But
gntdev_release() will clear that list, so make sure that only one of
those things happens at the same time.
Signed-off-by: Marek Marczykowski-Górecki <marmarek@xxxxxxxxxxxxxxxxxxxxxx>
Signed-off-by: David Vrabel <david.vrabel@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/xen/gntdev.c | 2 ++
1 file changed, 2 insertions(+)
--- a/drivers/xen/gntdev.c
+++ b/drivers/xen/gntdev.c
@@ -529,12 +529,14 @@ static int gntdev_release(struct inode *
pr_debug("priv %p\n", priv);
+ mutex_lock(&priv->lock);
while (!list_empty(&priv->maps)) {
map = list_entry(priv->maps.next, struct grant_map, next);
list_del(&map->next);
gntdev_put_map(NULL /* already removed */, map);
}
WARN_ON(!list_empty(&priv->freeable_maps));
+ mutex_unlock(&priv->lock);
if (use_ptemod)
mmu_notifier_unregister(&priv->mn, priv->mm);
Patches currently in stable-queue which might be from marmarek@xxxxxxxxxxxxxxxxxxxxxx are
queue-3.14/xen-gntdevt-fix-race-condition-in-gntdev_release.patch
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