Insertion into head of austere heap misses setting reverse link

The heap is maintained as a doubly linked list of objects but both
__AllocSmall() and __FreeSmall() are missing setup of the reverse link when
a new object is inserted at the head. This patch adds the necessary fix.

Signed-off-by: Paul Durrant <paul.durrant@citrix.com>
Reported-by: Gregory Jacklin <jackling@amazon.com>

diff --git a/src/xencrsh/austere.c b/src/xencrsh/austere.c
index c242006113c6128ff5df0a6e7246b6da99dcf257..6851475802b304727d2ad9cdb3a2484ed5f40967 100644 (file)
--- a/src/xencrsh/austere.c
+++ b/src/xencrsh/austere.c
@@ -262,6 +262,7 @@ __AllocSmall(
             SubHeap->Next->Prev = SubHeap->Prev;
         SubHeap->Prev = NULL;
         SubHeap->Next = AustereHeap.HeadSubHeap;
+        AustereHeap.HeadSubHeap->Prev = SubHeap;
         AustereHeap.HeadSubHeap = SubHeap;
     }
     return Res;
@@ -327,6 +328,7 @@ __FreeSmall(
             SubHeap->Next->Prev = SubHeap->Prev;
         SubHeap->Prev = NULL;
         SubHeap->Next = AustereHeap.HeadSubHeap;
+        AustereHeap.HeadSubHeap->Prev = SubHeap;
         AustereHeap.HeadSubHeap = SubHeap;
     }
 }