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From:   Sasha Levin <Alexander.Levin@microsoft.com>
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        "stable@vger.kernel.org" <stable@vger.kernel.org>
CC:     Ross Lagerwall <ross.lagerwall@citrix.com>,
        Boris Ostrovsky <boris.ostrovsky@oracle.com>,
        Sasha Levin <Alexander.Levin@microsoft.com>
Subject: [PATCH AUTOSEL for 4.14 104/110] xen/gntdev: Fix partial
 gntdev_mmap() cleanup
Thread-Topic: [PATCH AUTOSEL for 4.14 104/110] xen/gntdev: Fix partial
 gntdev_mmap() cleanup
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Date:   Sat, 3 Feb 2018 18:01:33 +0000
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From: Ross Lagerwall <ross.lagerwall@citrix.com>

[ Upstream commit cf2acf66ad43abb39735568f55e1f85f9844e990 ]

When cleaning up after a partially successful gntdev_mmap(), unmap the
successfully mapped grant pages otherwise Xen will kill the domain if
in debug mode (Attempt to implicitly unmap a granted PTE) or Linux will
kill the process and emit "BUG: Bad page map in process" if Xen is in
release mode.

This is only needed when use_ptemod is true because gntdev_put_map()
will unmap grant pages itself when use_ptemod is false.

Signed-off-by: Ross Lagerwall <ross.lagerwall@citrix.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
---
 drivers/xen/gntdev.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/xen/gntdev.c b/drivers/xen/gntdev.c
index d3391a1e3796..bd56653b9bbc 100644
--- a/drivers/xen/gntdev.c
+++ b/drivers/xen/gntdev.c
@@ -1071,8 +1071,10 @@ unlock_out:
 out_unlock_put:
 	mutex_unlock(&priv->lock);
 out_put_map:
-	if (use_ptemod)
+	if (use_ptemod) {
 		map->vma =3D NULL;
+		unmap_grant_pages(map, 0, map->count);
+	}
 	gntdev_put_map(priv, map);
 	return err;
 }
--=20
2.11.0