libxc: obtain correct length of p2m during core dumping

while implementing core dumping functionality for the libxl driver
of libvirt, I discovered an issue with mapping pages of a pv guest.

After dumping the core of a pv guest the domain was not cleared up
properly and some pages were not unmapped. This issue is similar
to the one reported here:
http://lists.xensource.com/archives/html/xen-devel/2011-05/msg01314.html

In xc_domain_dumpcore_via_callback in the file xc_core.c the function
xc_core_arch_map_p2m is called to map P2M_FL_ENTRIES pages to the variable p2m.
But to unmap the pages later, the dinfo->p2m_size has to be set accordingly.
This was not done, instead a variable named p2m_size was set.
This way P2M_FL_ENTRIES was always zero and the pages were left mapped.

[ This change should be considered for backport to relevant trees. ]

Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
Committed-by: Ian Jackson <ian.jackson@eu.citrix.com>

1 files changed, 1 insertions, 2 deletions

diff --git a/tools/libxc/xc_core.c b/tools/libxc/xc_core.c
index 720632de73..d711f1b727 100644
--- a/tools/libxc/xc_core.c
+++ b/tools/libxc/xc_core.c
@@ -468,7 +468,6 @@ xc_domain_dumpcore_via_callback(xc_interface *xch,
 
     int auto_translated_physmap;
     xen_pfn_t *p2m = NULL;
-    unsigned long p2m_size = 0;
     struct xen_dumpcore_p2m *p2m_array = NULL;
 
     uint64_t *pfn_array = NULL;
@@ -569,7 +568,7 @@ xc_domain_dumpcore_via_callback(xc_interface *xch,
         }
 
         sts = xc_core_arch_map_p2m(xch, dinfo->guest_width, &info, live_shinfo,
-                                   &p2m, &p2m_size);
+                                   &p2m, &dinfo->p2m_size);
         if ( sts != 0 )
             goto out;
     }