Alexandre Julliard : ntdll: Copy the context contents instead of the pointer on collided unwind.

[Alexandre Julliard]

Module: wine
Branch: master
Commit: 47f94fcf5f8e4be9fc418c2aa2cdf13b0d223ddc
URL:    https://gitlab.winehq.org/wine/wine/-/commit/47f94fcf5f8e4be9fc418c2aa2cdf13...

Author: Alexandre Julliard 
Date:   Mon Mar 25 18:04:37 2024 +0100

ntdll: Copy the context contents instead of the pointer on collided unwind.

Similar to how it's done on ARM platforms.

---

dlls/ntdll/signal_x86_64.c | 44 ++++++++++++--------------------------------
 1 file changed, 12 insertions(+), 32 deletions(-)

diff --git a/dlls/ntdll/signal_x86_64.c b/dlls/ntdll/signal_x86_64.c
index 80636037cb7..6930f4df34e 100644
--- a/dlls/ntdll/signal_x86_64.c
+++ b/dlls/ntdll/signal_x86_64.c
@@ -210,6 +210,7 @@ NTSTATUS call_seh_handlers( EXCEPTION_RECORD *rec, CONTEXT *orig_context )
     DISPATCHER_CONTEXT dispatch;
     CONTEXT context;
     NTSTATUS status;
+    ULONG_PTR frame;

context = *orig_context;
     context.ContextFlags &= ~0x40; /* Clear xstate flag. */
@@ -246,16 +247,10 @@ NTSTATUS call_seh_handlers( EXCEPTION_RECORD *rec, CONTEXT *orig_context )
                 rec->ExceptionFlags |= EXCEPTION_NESTED_CALL;
                 TRACE( "nested exception\n" );
                 break;
-            case ExceptionCollidedUnwind: {
-                ULONG64 frame;
-
-                context = *dispatch.ContextRecord;
-                dispatch.ContextRecord = &context;
-                RtlVirtualUnwind( UNW_FLAG_NHANDLER, dispatch.ImageBase,
-                        dispatch.ControlPc, dispatch.FunctionEntry,
-                        &context, NULL, &frame, NULL );
+            case ExceptionCollidedUnwind:
+                RtlVirtualUnwind( UNW_FLAG_NHANDLER, dispatch.ImageBase, dispatch.ControlPc,
+                                  dispatch.FunctionEntry, &context, NULL, &frame, NULL );
                 goto unwind_done;
-            }
             default:
                 return STATUS_INVALID_DISPOSITION;
             }
@@ -277,17 +272,11 @@ NTSTATUS call_seh_handlers( EXCEPTION_RECORD *rec, CONTEXT *orig_context )
                 rec->ExceptionFlags |= EXCEPTION_NESTED_CALL;
                 TRACE( "nested exception\n" );
                 break;
-            case ExceptionCollidedUnwind: {
-                ULONG64 frame;
-
-                context = *dispatch.ContextRecord;
-                dispatch.ContextRecord = &context;
-                RtlVirtualUnwind( UNW_FLAG_NHANDLER, dispatch.ImageBase,
-                        dispatch.ControlPc, dispatch.FunctionEntry,
-                        &context, NULL, &frame, NULL );
+            case ExceptionCollidedUnwind:
+                RtlVirtualUnwind( UNW_FLAG_NHANDLER, dispatch.ImageBase, dispatch.ControlPc,
+                                  dispatch.FunctionEntry, &context, NULL, &frame, NULL );
                 teb_frame = teb_frame->Prev;
                 goto unwind_done;
-            }
             default:
                 return STATUS_INVALID_DISPOSITION;
             }
@@ -447,11 +436,12 @@ DWORD __cdecl unwind_exception_handler( EXCEPTION_RECORD *rec, EXCEPTION_REGISTR
     dispatch->ImageBase        = unwind_frame->dispatch->ImageBase;
     dispatch->FunctionEntry    = unwind_frame->dispatch->FunctionEntry;
     dispatch->EstablisherFrame = unwind_frame->dispatch->EstablisherFrame;
-    dispatch->ContextRecord    = unwind_frame->dispatch->ContextRecord;
     dispatch->LanguageHandler  = unwind_frame->dispatch->LanguageHandler;
     dispatch->HandlerData      = unwind_frame->dispatch->HandlerData;
     dispatch->HistoryTable     = unwind_frame->dispatch->HistoryTable;
     dispatch->ScopeIndex       = unwind_frame->dispatch->ScopeIndex;
+    *dispatch->ContextRecord   = *unwind_frame->dispatch->ContextRecord;
+    dispatch->ContextRecord->ContextFlags &= ~0x40;
     TRACE( "detected collided unwind\n" );
     return ExceptionCollidedUnwind;
 }
@@ -728,6 +718,7 @@ void WINAPI RtlUnwindEx( PVOID end_frame, PVOID target_ip, EXCEPTION_RECORD *rec
     DISPATCHER_CONTEXT dispatch;
     CONTEXT new_context;
     NTSTATUS status;
+    ULONG_PTR frame;
     DWORD i;

RtlCaptureContext( context );
@@ -783,12 +774,7 @@ void WINAPI RtlUnwindEx( PVOID end_frame, PVOID target_ip, EXCEPTION_RECORD *rec
             if (dispatch.EstablisherFrame == (ULONG64)end_frame) rec->ExceptionFlags |= EXCEPTION_TARGET_UNWIND;
             if (call_unwind_handler( rec, &dispatch ) == ExceptionCollidedUnwind)
             {
-                ULONG64 frame;
-
-                new_context = *dispatch.ContextRecord;
-                new_context.ContextFlags &= ~0x40;
-                *context = new_context;
-                dispatch.ContextRecord = context;
+                new_context = *context;
                 RtlVirtualUnwind( UNW_FLAG_NHANDLER, dispatch.ImageBase,
                         dispatch.ControlPc, dispatch.FunctionEntry,
                         &new_context, NULL, &frame, NULL );
@@ -808,14 +794,8 @@ void WINAPI RtlUnwindEx( PVOID end_frame, PVOID target_ip, EXCEPTION_RECORD *rec
                 dispatch.EstablisherFrame = (ULONG64)teb_frame;
                 if (call_teb_unwind_handler( rec, &dispatch, teb_frame ) == ExceptionCollidedUnwind)
                 {
-                    ULONG64 frame;
-
                     teb_frame = __wine_pop_frame( teb_frame );
-
-                    new_context = *dispatch.ContextRecord;
-                    new_context.ContextFlags &= ~0x40;
-                    *context = new_context;
-                    dispatch.ContextRecord = context;
+                    new_context = *context;
                     RtlVirtualUnwind( UNW_FLAG_NHANDLER, dispatch.ImageBase,
                             dispatch.ControlPc, dispatch.FunctionEntry,
                             &new_context, NULL, &frame, NULL );