X-Git-Url: https://git.ucc.asn.au/?a=blobdiff_plain;f=Kernel%2Farch%2Fx86%2Fmm_virt.c;h=8fe1b4aaafe626492650bd895a0c5bf0b033b75a;hb=f7f1b08ec035ddef61218b51d8e9a9d4c1ee7b9a;hp=25da74336ca5f2182ff8ab1145900e42279be49f;hpb=0c641aba30830a011f7e82aca119c541884d8aab;p=tpg%2Facess2.git

diff --git a/Kernel/arch/x86/mm_virt.c b/Kernel/arch/x86/mm_virt.c
index 25da7433..8fe1b4aa 100644
--- a/Kernel/arch/x86/mm_virt.c
+++ b/Kernel/arch/x86/mm_virt.c
@@ -105,10 +105,18 @@ void MM_PageFault(Uint Addr, Uint ErrorCode, tRegs *Regs)
 	 && gaPageTable[Addr>>12] & PF_COW )
 	{
 		tPAddr	paddr;
-		paddr = MM_DuplicatePage( Addr );
-		MM_DerefPhys( gaPageTable[Addr>>12] & ~0xFFF );
-		gaPageTable[Addr>>12] &= PF_USER;
-		gaPageTable[Addr>>12] |= paddr|PF_PRESENT|PF_WRITE;
+		if(MM_GetRefCount( gaPageTable[Addr>>12] & ~0xFFF ) == 0)
+		{
+			gaPageTable[Addr>>12] &= ~PF_COW;
+			gaPageTable[Addr>>12] |= PF_PRESENT|PF_WRITE;
+		}
+		else
+		{
+			paddr = MM_DuplicatePage( Addr );
+			MM_DerefPhys( gaPageTable[Addr>>12] & ~0xFFF );
+			gaPageTable[Addr>>12] &= PF_USER;
+			gaPageTable[Addr>>12] |= paddr|PF_PRESENT|PF_WRITE;
+		}
 		INVLPG( Addr & ~0xFFF );
 		//LEAVE('-')
 		return;