[PATCH 1/1] ntdll: Stop unwinding on access violation.

[Dylan Donnell]

From: Dylan Donnell

---
 dlls/ntdll/signal_x86_64.c | 34 +++++++++++++++++++++++++---------
 1 file changed, 25 insertions(+), 9 deletions(-)

diff --git a/dlls/ntdll/signal_x86_64.c b/dlls/ntdll/signal_x86_64.c
index 3d4bd23e8ff..6aa389dacc5 100644
--- a/dlls/ntdll/signal_x86_64.c
+++ b/dlls/ntdll/signal_x86_64.c
@@ -866,6 +866,13 @@ BOOLEAN WINAPI RtlIsProcessorFeaturePresent( UINT feature )
     return feature < PROCESSOR_FEATURE_MAX && user_shared_data->ProcessorFeatures[feature];
 }

+static LONG WINAPI walk_frame_chain_handler( EXCEPTION_POINTERS *eptr )
+{
+    if (eptr->ExceptionRecord->ExceptionCode == STATUS_ACCESS_VIOLATION)
+        return EXCEPTION_EXECUTE_HANDLER;
+
+    return EXCEPTION_CONTINUE_SEARCH;
+}

/*************************************************************************
  *		RtlWalkFrameChain (NTDLL.@)
@@ -882,17 +889,26 @@ ULONG WINAPI RtlWalkFrameChain( void **buffer, ULONG count, ULONG flags )

RtlCaptureContext( &context );

-    for (i = 0; i < count; i++)
+    __TRY
     {
-        func = RtlLookupFunctionEntry( context.Rip, &base, &table );
-        if (RtlVirtualUnwind2( UNW_FLAG_NHANDLER, base, context.Rip, func, &context, NULL,
-                               &data, &frame, NULL, NULL, NULL, &handler, 0 ))
-            break;
-        if (!context.Rip) break;
-        if (!frame || !is_valid_frame( frame )) break;
-        if (context.Rsp == (ULONG_PTR)NtCurrentTeb()->Tib.StackBase) break;
-        if (i >= skip) buffer[num_entries++] = (void *)context.Rip;
+        for (i = 0; i < count; i++)
+        {
+            func = RtlLookupFunctionEntry( context.Rip, &base, &table );
+            if (RtlVirtualUnwind2( UNW_FLAG_NHANDLER, base, context.Rip, func, &context, NULL,
+                                &data, &frame, NULL, NULL, NULL, &handler, 0 ))
+                break;
+            if (!context.Rip) break;
+            if (!frame || !is_valid_frame( frame )) break;
+            if (context.Rsp == (ULONG_PTR)NtCurrentTeb()->Tib.StackBase) break;
+            if (i >= skip) buffer[num_entries++] = (void *)context.Rip;
+        }
+    }
+    __EXCEPT(walk_frame_chain_handler)
+    {
+        TRACE( "access violation when unwinding with context.Rip %p\n", (void *)context.Rip );
     }
+    __ENDTRY
+
     return num_entries;
 }