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| author | Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com> | 2015-06-26 03:28:24 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2015-08-16 20:51:49 -0700 |
| commit | 9e6c072a69d87100808d16279d60e9f857291340 (patch) | |
| tree | 7ad0b696eb8af8bdca1fe76328ff389c1e1f8d1b | |
| parent | b60d3eee854b881b3f7a478c8b622cbef72d4c4e (diff) | |
| download | lwn-9e6c072a69d87100808d16279d60e9f857291340.tar.gz lwn-9e6c072a69d87100808d16279d60e9f857291340.zip | |
xen/gntdevt: Fix race condition in gntdev_release()
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@invisiblethingslab.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/xen/gntdev.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/drivers/xen/gntdev.c b/drivers/xen/gntdev.c index 073b4a19a8b0..ff3c98f1ea95 100644 --- a/drivers/xen/gntdev.c +++ b/drivers/xen/gntdev.c @@ -529,12 +529,14 @@ static int gntdev_release(struct inode *inode, struct file *flip) 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); |