One of the error paths in p2m_add_foreign could call put_page with a
NULL page, thus triggering a fault.
Split the checks into two different if statements, so the appropriate
error path can be taken.
Fixes: 173ae325026bd ('x86/p2m: tidy p2m_add_foreign() a little')
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
---
xen/arch/x86/mm/p2m.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)
diff --git a/xen/arch/x86/mm/p2m.c b/xen/arch/x86/mm/p2m.c
index 487959b121..a4ebfc9b21 100644
--- a/xen/arch/x86/mm/p2m.c
+++ b/xen/arch/x86/mm/p2m.c
@@ -2601,8 +2601,13 @@ static int p2m_add_foreign(struct domain *tdom, unsigned long fgfn,
* ram_rw | ram_logdirty | ram_ro | paging_out.
*/
page = get_page_from_gfn(fdom, fgfn, &p2mt, P2M_ALLOC);
- if ( !page ||
- !p2m_is_ram(p2mt) || p2m_is_shared(p2mt) || p2m_is_hole(p2mt) )
+ if ( !page )
+ {
+ rc = -EINVAL;
+ goto out;
+ }
+
+ if ( !p2m_is_ram(p2mt) || p2m_is_shared(p2mt) || p2m_is_hole(p2mt) )
{
rc = -EINVAL;
goto put_one;
--
2.29.2