msvcrt: Write memory forward in memset.

Instead of going backward, which breaks the Linux kernel transparent huge pages allocation assumptions. This can be reproduced by calling memset on large, newly allocated, memory regions. Signed-off-by: Rémi Bernon <rbernon@codeweavers.com> Signed-off-by: Piotr Caban <piotr@codeweavers.com> Signed-off-by: Alexandre Julliard <julliard@winehq.org>

msvcrt: Write memory forward in memset.
7c046c7a · Rémi Bernon · Alexandre Julliard · f7ac9f30 · 7c046c7a
Commit 7c046c7a authored Oct 21, 2021 by Rémi Bernon Committed by Alexandre Julliard Oct 25, 2021
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string.c dlls/msvcrt/string.c +8 -7

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--- a/dlls/msvcrt/string.c
+++ b/dlls/msvcrt/string.c
@@ -2857,13 +2857,14 @@ void * __cdecl memcpy(void *dst, const void *src, size_t n)

 static inline void memset_aligned_32(unsigned char *d, uint64_t v, size_t n)
 {
-    while (n >= 32)
-    {
-        *(uint64_t *)(d + n - 32) = v;
-        *(uint64_t *)(d + n - 24) = v;
-        *(uint64_t *)(d + n - 16) = v;
-        *(uint64_t *)(d + n -  8) = v;
-        n -= 32;
+    unsigned char *end = d + n;
+    while (d < end)
+    {
+        *(uint64_t *)(d + 0) = v;
+        *(uint64_t *)(d + 8) = v;
+        *(uint64_t *)(d + 16) = v;
+        *(uint64_t *)(d + 24) = v;
+        d += 32;
    }
 }