4.4-stable review patch. If anyone has any objections, please let me know.
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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 Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/xen/gntdev.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
--- a/drivers/xen/gntdev.c +++ b/drivers/xen/gntdev.c @@ -874,8 +874,10 @@ unlock_out: out_unlock_put: mutex_unlock(&priv->lock); out_put_map: - if (use_ptemod) + if (use_ptemod) { map->vma = NULL; + unmap_grant_pages(map, 0, map->count); + } gntdev_put_map(priv, map); return err; }