[PATCH v3 10/10] ntdll: Tweak KeUserModeCallback to please Valgrind and GDB.

[Rémi Bernon]

From: Rémi Bernon

This is a hack, but valgrind heuristics are having a hard time with
the stack manipulation around here. This silents some annoying reports.
---
 dlls/ntdll/unix/signal_i386.c   |  2 +-
 dlls/ntdll/unix/signal_x86_64.c | 14 +++++++++++++-
 2 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/dlls/ntdll/unix/signal_i386.c b/dlls/ntdll/unix/signal_i386.c
index caa635881bb..09c61025db9 100644
--- a/dlls/ntdll/unix/signal_i386.c
+++ b/dlls/ntdll/unix/signal_i386.c
@@ -1669,7 +1669,7 @@ NTSTATUS WINAPI KeUserModeCallback( ULONG id, const void *args, ULONG len, void
     *(--stack) = len;
     *(--stack) = (ULONG_PTR)args_data;
     *(--stack) = id;
-    *(--stack) = 0xdeadbabe;
+    *(--stack) = *(ULONG_PTR *)frame->esp;

return call_user_mode_callback( pKiUserCallbackDispatcher, stack, ret_ptr, ret_len, NtCurrentTeb() );
 }
diff --git a/dlls/ntdll/unix/signal_x86_64.c b/dlls/ntdll/unix/signal_x86_64.c
index 39373b5f3dc..079b5549443 100644
--- a/dlls/ntdll/unix/signal_x86_64.c
+++ b/dlls/ntdll/unix/signal_x86_64.c
@@ -64,6 +64,12 @@
 #ifdef __APPLE__
 # include <mach/mach.h>
 #endif
+#ifdef HAVE_VALGRIND_VALGRIND_H
+# include <valgrind/valgrind.h>
+#endif
+#ifdef HAVE_VALGRIND_MEMCHECK_H
+# include <valgrind/memcheck.h>
+#endif

#define NONAMELESSUNION
 #define NONAMELESSSTRUCT
@@ -1716,12 +1722,18 @@ NTSTATUS WINAPI KeUserModeCallback( ULONG id, const void *args, ULONG len, void
     if ((char *)ntdll_get_thread_data()->kernel_stack + min_kernel_stack > (char *)&frame)
         return STATUS_STACK_OVERFLOW;

+#if defined(VALGRIND_MAKE_MEM_UNDEFINED)
+    VALGRIND_MAKE_MEM_UNDEFINED( (char *)stack - 0x100, (char *)frame->rsp - (char *)stack + 0x100 );
+#elif defined(VALGRIND_MAKE_WRITABLE)
+    VALGRIND_MAKE_WRITABLE( (char *)stack - 0x100, (char *)frame->rsp - (char *)stack + 0x100 );
+#endif
+
     memcpy( args_data, args, len );
     *(--stack) = 0;
     *(--stack) = len;
     *(--stack) = (ULONG_PTR)args_data;
     *(--stack) = id;
-    *(--stack) = 0xdeadbabe;
+    *(--stack) = *(ULONG_PTR *)frame->rsp;

return call_user_mode_callback( pKiUserCallbackDispatcher, stack, ret_ptr, ret_len, NtCurrentTeb() );
 }