sys: DEBUGRANDTEST()

src/sys/create.c

@@ -690,7 +690,7 @@ static NTSTATUS FspFsvolCreateTryOpen(PIRP Irp, const FSP_FSCTL_TRANSACT_RSP *Re
     FSP_FSCTL_TRANSACT_REQ *Request = FspIrpRequest(Irp);
     BOOLEAN Success;
 
-    Success = FspFileNodeTryAcquireExclusive(FileNode, Both);
+    Success = DEBUGRANDTEST(90, TRUE) && FspFileNodeTryAcquireExclusive(FileNode, Both);
     if (!Success)
     {
         /* repost the IRP to retry later */

src/sys/debug.c

@@ -261,4 +261,22 @@ const char *FsInformationClassSym(FS_INFORMATION_CLASS FsInformationClass)
         return "FS_INFORMATION_CLASS:Unknown";
     }
 }
+
+ULONG DebugRandom(VOID)
+{
+    static KSPIN_LOCK SpinLock = 0;
+    static ULONG Seed = 1;
+    KIRQL Irql;
+    ULONG Result;
+
+    KeAcquireSpinLock(&SpinLock, &Irql);
+
+    /* see ucrt sources */
+    Seed = Seed * 214013 + 2531011;
+    Result = (Seed >> 16) & 0x7fff;
+
+    KeReleaseSpinLock(&SpinLock, Irql);
+
+    return Result;
+}
 #endif

src/sys/driver.h

@@ -56,7 +56,7 @@ extern __declspec(selectany) int fsp_bp = 1;
 #define DEBUGBREAK()                    \
     do                                  \
     {                                   \
-        static int bp = 1;          \
+        static int bp = 1;              \
         if (bp && fsp_bp && !KD_DEBUGGER_NOT_PRESENT)\
             DbgBreakPoint();            \
     } while (0,0)
@@ -64,6 +64,13 @@ extern __declspec(selectany) int fsp_bp = 1;
 #define DEBUGBREAK()                    do {} while (0,0)
 #endif
 
+/* DEBUGRANDTEST */
+#if DBG
+#define DEBUGRANDTEST(Percent, Default) (DebugRandom() <= (Percent) * 0x7fff / 100 ? (Default) : !(Default))
+#else
+#define DEBUGRANDTEST(Percent, Default) (Default)
+#endif
+
 /* FSP_ENTER/FSP_LEAVE */
 #if DBG
 #define FSP_DEBUGLOG_(fmt, rfmt, ...)   \
@@ -632,6 +639,7 @@ const char *IrpMinorFunctionSym(UCHAR MajorFunction, UCHAR MinorFunction);
 const char *IoctlCodeSym(ULONG ControlCode);
 const char *FileInformationClassSym(FILE_INFORMATION_CLASS FileInformationClass);
 const char *FsInformationClassSym(FS_INFORMATION_CLASS FsInformationClass);
+ULONG DebugRandom(VOID);
 static inline
 VOID FspDebugLogIrp(const char *func, PIRP Irp, NTSTATUS Result)
 {