[PATCH 0/1] MR7870: kernelbase: fix racing condition in GlobalMemoryStatusEx()

[Rastislav Stanik (＠rastos)]

use a critical section to guard access to local static variable with cached information

Wine-Bug: https://bugs.winehq.org/show_bug.cgi?id=58082

-- 
https://gitlab.winehq.org/wine/wine/-/merge_requests/7870

[PATCH 1/1] kernelbase: fix racing condition in GlobalMemoryStatusEx()

[Rastislav Stanik]

From: Rastislav Stanik <git(a)rastos.org>

use a critical section to guard access to local static variable with cached information

Wine-Bug: https://bugs.winehq.org/show_bug.cgi?id=58082
---
 dlls/kernelbase/memory.c | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/dlls/kernelbase/memory.c b/dlls/kernelbase/memory.c
index 0be178f6ab7..63a2f8e8698 100644
--- a/dlls/kernelbase/memory.c
+++ b/dlls/kernelbase/memory.c
@@ -42,6 +42,14 @@ WINE_DECLARE_DEBUG_CHANNEL(virtual);
 WINE_DECLARE_DEBUG_CHANNEL(globalmem);
 
 
+static CRITICAL_SECTION memory_section;
+static CRITICAL_SECTION_DEBUG critsect_debug =
+{
+    0, 0, &memory_section,
+    { &critsect_debug.ProcessLocksList, &critsect_debug.ProcessLocksList },
+      0, 0, { (DWORD_PTR)(__FILE__ ": memory_section") }
+};
+static CRITICAL_SECTION memory_section = { &critsect_debug, -1, 0, 0, 0, 0 };
 
 static CROSS_PROCESS_WORK_LIST *open_cross_process_connection( HANDLE process )
 {
@@ -1343,12 +1351,15 @@ BOOL WINAPI DECLSPEC_HOTPATCH GlobalMemoryStatusEx( MEMORYSTATUSEX *status )
         SetLastError( ERROR_INVALID_PARAMETER );
         return FALSE;
     }
+    RtlEnterCriticalSection(&memory_section);
     if ((NtGetTickCount() - last_check) < 1000)
     {
 	*status = cached_status;
+	RtlLeaveCriticalSection(&memory_section);
 	return TRUE;
     }
-    last_check = NtGetTickCount();
+    else
+        RtlLeaveCriticalSection(&memory_section);
 
     if (!set_ntstatus( NtQuerySystemInformation( SystemBasicInformation,
                                                  &basic_info, sizeof(basic_info), NULL )) ||
@@ -1380,7 +1391,10 @@ BOOL WINAPI DECLSPEC_HOTPATCH GlobalMemoryStatusEx( MEMORYSTATUSEX *status )
                      status->dwMemoryLoad, status->ullTotalPhys, status->ullAvailPhys, status->ullTotalPageFile,
                      status->ullAvailPageFile, status->ullTotalVirtual, status->ullAvailVirtual );
 
+    RtlEnterCriticalSection(&memory_section);
     cached_status = *status;
+    last_check = NtGetTickCount();
+    RtlLeaveCriticalSection(&memory_section);
     return TRUE;
 }
 
-- 
GitLab

https://gitlab.winehq.org/wine/wine/-/merge_requests/7870