[Xen-devel] [PATCH] tools/libxc: Set max_elem to zero in xc_lockprof_query_number()

[Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>]

If max_elem is not zero then hypervisor's spinlock_profile_ucopy_elem()
will attempt to copy profile data into user's data buffer. Since this
buffer is explicitly set to (the equivalent of) NULL the copy will fail,
causing xenlockprof to fail as well.

Signed-off-by: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>
---
 tools/libxc/xc_misc.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/tools/libxc/xc_misc.c b/tools/libxc/xc_misc.c
index 4143de6..e253a58 100644
--- a/tools/libxc/xc_misc.c
+++ b/tools/libxc/xc_misc.c
@@ -320,6 +320,7 @@ int xc_lockprof_query_number(xc_interface *xch,
     DECLARE_SYSCTL;
 
     sysctl.cmd = XEN_SYSCTL_lockprof_op;
+    sysctl.u.lockprof_op.max_elem = 0;
     sysctl.u.lockprof_op.cmd = XEN_SYSCTL_LOCKPROF_query;
     set_xen_guest_handle(sysctl.u.lockprof_op.data, HYPERCALL_BUFFER_NULL);
 
-- 
1.8.1.4


_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel