When __p2m_get_mem_access gets called, the p2m lock is already taken
by either get_page_from_gva or p2m_get_mem_access.
Possible code paths:
1) -> get_page_from_gva
-> p2m_mem_access_check_and_get_page
-> __p2m_get_mem_access
2) -> p2m_get_mem_access
-> __p2m_get_mem_access
In both cases if __p2m_get_mem_access subsequently gets to
call p2m_lookup (happens if !radix_tree_lookup(...)), a hypervisor
hang will occur, since p2m_lookup also spin-locks on the p2m lock.
This bug-fix simply replaces the p2m_lookup call from __p2m_get_mem_access
with a call to __p2m_lookup.
Signed-off-by: Corneliu ZUZU <cz...@bitdefender.com>
---
xen/arch/arm/p2m.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/xen/arch/arm/p2m.c b/xen/arch/arm/p2m.c
index 2190908..a9157e5 100644
--- a/xen/arch/arm/p2m.c
+++ b/xen/arch/arm/p2m.c
@@ -490,7 +490,7 @@ static int __p2m_get_mem_access(struct domain *d, gfn_t gfn,
* No setting was found in the Radix tree. Check if the
* entry exists in the page-tables.
*/
- paddr_t maddr = p2m_lookup(d, gfn_x(gfn) << PAGE_SHIFT, NULL);
+ paddr_t maddr = __p2m_lookup(d, gfn_x(gfn) << PAGE_SHIFT, NULL);
if ( INVALID_PADDR == maddr )
return -ESRCH;
--
2.5.0
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel
