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LazDebuggerFp: Fix removing breakpoint, while thread-worker is still setting it. (possible race condition)

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This commit is contained in:
Martin 2023-07-26 17:14:53 +02:00
parent 2a6fa122d1
commit 0e1f76f481
2 changed files with 50 additions and 52 deletions
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45
components/lazdebuggers/lazdebuggerfp/fpdebugdebugger.pas
View File

@ -152,7 +152,7 @@ type
public
constructor Create(ADebugger: TFpDebugDebuggerBase; ADbgBreakPoint: TFPBreakpoint); overload;
procedure AbortSetBreak; override;
procedure RemoveBreakPoint_DecRef; override;
property DbgBreakPoint: TFPBreakpoint read FDbgBreakPoint;
end;
{ TFpThreadWorkerBreakPointRemoveUpdate }
@ -578,6 +578,7 @@ type
FBrkLogStackLimit: Integer;
FBrkLogStackResult: array of String;
FBrkLogExpr, FBrkLogResult: String;
procedure MaybeAbortWorker(AWait: Boolean = false);
procedure SetBreak;
procedure ResetBreak;
procedure ThreadLogExpression;
@ -1102,9 +1103,9 @@ begin
DecRef;
end
else
FResetBreakPoint := True;
FResetBreakPoint := 1;
if FResetBreakPoint then begin
if FResetBreakPoint <> 0 then begin
if InternalBreakpoint <> nil then begin
WorkItem := TFpThreadWorkerBreakPointRemoveUpdate.Create(FDebugger, InternalBreakpoint);
FpDebugger.FWorkQueue.PushItem(WorkItem);
@ -1150,15 +1151,8 @@ end;
procedure TFpThreadWorkerBreakPointSetUpdate.AbortSetBreak;
begin
FResetBreakPoint := True;
RequestStop;
end;
procedure TFpThreadWorkerBreakPointSetUpdate.RemoveBreakPoint_DecRef;
begin
assert(system.ThreadID = classes.MainThreadID, 'TFpThreadWorkerBreakPointSetUpdate.RemoveBreakPoint_DecRef: system.ThreadID = classes.MainThreadID');
InterLockedExchange(FResetBreakPoint, 1);
FDbgBreakPoint := nil;
UnQueue_DecRef;
end;
{ TFpThreadWorkerBreakPointRemoveUpdate }
@ -1879,11 +1873,26 @@ begin
result := nil;
end;
procedure TFPBreakpoint.MaybeAbortWorker(AWait: Boolean);
begin
if FThreadWorker <> nil then begin
assert(FThreadWorker is TFpThreadWorkerBreakPointSetUpdate, 'TFPBreakpoint.ResetBreak: FThreadWorker is TFpThreadWorkerBreakPointSetUpdate');
assert(FInternalBreakpoint = nil, 'TFPBreakpoint.ResetBreak: FInternalBreakpoint = nil');
FThreadWorker.AbortSetBreak;
if AWait then
TFpDebugDebugger(Debugger).FWorkQueue.WaitForItem(FThreadWorker);
FThreadWorker.DecRef;
FThreadWorker := nil;
end;
end;
procedure TFPBreakpoint.SetBreak;
begin
debuglnEnter(DBG_BREAKPOINTS, ['>> TFPBreakpoint.SetBreak ADD ',FSource,':',FLine,'/',dbghex(Address),' ' ]);
assert(FThreadWorker = nil, 'TFPBreakpoint.SetBreak: FThreadWorker = nil');
assert((FThreadWorker = nil) or ( (FThreadWorker is TFpThreadWorkerBreakPointSetUpdate) and (TFpThreadWorkerBreakPointSetUpdate(FThreadWorker).DbgBreakPoint = nil) ), 'TFPBreakpoint.SetBreak: (FThreadWorker = nil) or ( (FThreadWorker is TFpThreadWorkerBreakPointSetUpdate) and (TFpThreadWorkerBreakPointSetUpdate(FThreadWorker).DbgBreakPoint = nil) )');
assert(FInternalBreakpoint=nil);
MaybeAbortWorker;
FThreadWorker := TFpThreadWorkerBreakPointSetUpdate.Create(TFpDebugDebugger(Debugger), Self);
TFpDebugDebugger(Debugger).FWorkQueue.PushItem(FThreadWorker);
@ -1900,12 +1909,8 @@ begin
FIsSet:=false;
if FThreadWorker <> nil then begin
debugln(DBG_BREAKPOINTS, ['>> TFPBreakpoint.ResetBreak CANCEL / REMOVE ',FSource,':',FLine,'/',dbghex(Address),' ' ]);
assert(FThreadWorker is TFpThreadWorkerBreakPointSetUpdate, 'TFPBreakpoint.ResetBreak: FThreadWorker is TFpThreadWorkerBreakPointSetUpdate');
assert(FInternalBreakpoint = nil, 'TFPBreakpoint.ResetBreak: FInternalBreakpoint = nil');
FThreadWorker.AbortSetBreak;
FThreadWorker.RemoveBreakPoint_DecRef;
FThreadWorker.DecRef;
FThreadWorker := nil;
MaybeAbortWorker;
exit;
end;
@ -2018,13 +2023,7 @@ begin
If the next pause is a hit on this breakpoint, then it will be ignored
*)
ResetBreak;
if FThreadWorker <> nil then begin
FThreadWorker.AbortSetBreak;
FThreadWorker.RemoveBreakPoint_DecRef;
FThreadWorker.DecRef;
FThreadWorker := nil;
end;
MaybeAbortWorker(True);
inherited Destroy;
end;

57
components/lazdebuggers/lazdebuggerfp/fpdebugdebuggerworkthreads.pas
View File

@ -299,7 +299,6 @@ type
TFpThreadWorkerBreakPoint = class(TFpDbgDebggerThreadWorkerItem)
public
procedure RemoveBreakPoint_DecRef; virtual;
procedure AbortSetBreak; virtual;
end;
@ -317,7 +316,7 @@ type
FWatchScope: TDBGWatchPointScope;
FWatchKind: TDBGWatchPointKind;
protected
FResetBreakPoint: Boolean;
FResetBreakPoint: longint;
procedure UpdateBrkPoint_DecRef(Data: PtrInt = 0); virtual; abstract;
procedure DoExecute; override;
public
@ -1392,11 +1391,6 @@ end;
{ TFpThreadWorkerBreakPoint }
procedure TFpThreadWorkerBreakPoint.RemoveBreakPoint_DecRef;
begin
//
end;
procedure TFpThreadWorkerBreakPoint.AbortSetBreak;
begin
//
@ -1411,32 +1405,37 @@ var
R: TFpValue;
s: TFpDbgValueSize;
begin
case FKind of
bpkAddress:
FInternalBreakpoint := FDebugger.DbgController.CurrentProcess.AddBreak(FAddress, True);
bpkSource:
FInternalBreakpoint := FDebugger.DbgController.CurrentProcess.AddBreak(FSource, FLine, True);
bpkData: begin
CurContext := FDebugger.DbgController.CurrentProcess.FindSymbolScope(FThreadId, FStackFrame);
if CurContext <> nil then begin
WatchPasExpr := TFpPascalExpression.Create(FWatchData, CurContext, True);
WatchPasExpr.IntrinsicPrefix := TFpDebugDebuggerProperties(FDebugger.GetProperties).IntrinsicPrefix;
WatchPasExpr.AutoDeref := TFpDebugDebuggerProperties(FDebugger.GetProperties).AutoDeref;
WatchPasExpr.Parse;
R := WatchPasExpr.ResultValue; // Address and Size
// TODO: Cache current value
if WatchPasExpr.Valid and IsTargetNotNil(R.Address) and R.GetSize(s) then begin
// pass context
FInternalBreakpoint := FDebugger.DbgController.CurrentProcess.AddWatch(R.Address.Address, SizeToFullBytes(s), FWatchKind, FWatchScope);
if InterlockedExchange(FResetBreakPoint, 0) = 0 then begin
case FKind of
bpkAddress:
FInternalBreakpoint := FDebugger.DbgController.CurrentProcess.AddBreak(FAddress, True);
bpkSource:
FInternalBreakpoint := FDebugger.DbgController.CurrentProcess.AddBreak(FSource, FLine, True);
bpkData: begin
CurContext := FDebugger.DbgController.CurrentProcess.FindSymbolScope(FThreadId, FStackFrame);
if CurContext <> nil then begin
WatchPasExpr := TFpPascalExpression.Create(FWatchData, CurContext, True);
WatchPasExpr.IntrinsicPrefix := TFpDebugDebuggerProperties(FDebugger.GetProperties).IntrinsicPrefix;
WatchPasExpr.AutoDeref := TFpDebugDebuggerProperties(FDebugger.GetProperties).AutoDeref;
WatchPasExpr.Parse;
R := WatchPasExpr.ResultValue; // Address and Size
// TODO: Cache current value
if WatchPasExpr.Valid and IsTargetNotNil(R.Address) and R.GetSize(s) then begin
// pass context
FInternalBreakpoint := FDebugger.DbgController.CurrentProcess.AddWatch(R.Address.Address, SizeToFullBytes(s), FWatchKind, FWatchScope);
end;
WatchPasExpr.Free;
CurContext.ReleaseReference;
end;
WatchPasExpr.Free;
CurContext.ReleaseReference;
end;
end;
end;
if FResetBreakPoint then begin
FDebugger.DbgController.CurrentProcess.RemoveBreak(FInternalBreakpoint);
FreeAndNil(FInternalBreakpoint);
if InterlockedExchange(FResetBreakPoint, 0) = 1 then begin
if (FInternalBreakpoint <> nil) then begin
FDebugger.DbgController.CurrentProcess.RemoveBreak(FInternalBreakpoint);
FreeAndNil(FInternalBreakpoint);
end;
end;
Queue(@UpdateBrkPoint_DecRef);
end;