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-rw-r--r--linux-user/syscall.c9
1 files changed, 9 insertions, 0 deletions
diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index 6bdf4e6..ae08c9e 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -797,6 +797,15 @@ abi_long do_brk(abi_ulong new_brk)
MAP_ANON|MAP_PRIVATE, 0, 0));
if (mapped_addr == brk_page) {
+ /* Heap contents are initialized to zero, as for anonymous
+ * mapped pages. Technically the new pages are already
+ * initialized to zero since they *are* anonymous mapped
+ * pages, however we have to take care with the contents that
+ * come from the remaining part of the previous page: it may
+ * contains garbage data due to a previous heap usage (grown
+ * then shrunken). */
+ memset(g2h(target_brk), 0, brk_page - target_brk);
+
target_brk = new_brk;
brk_page = HOST_PAGE_ALIGN(target_brk);
DEBUGF_BRK("%#010x (mapped_addr == brk_page)\n", target_brk);
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