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Report From: Delphi-BCB/IDE/Save Desktop [ Add a report in this area ]

Report #: 61289

Status: Closed

Improper use of TThead.Suspend in LoadDesktop

Project: Delphi

Build #: 11.0.2902.10471

Version: 11.2

Submitted By: Sebastian Zierer

Report Type: Crash / Data loss / Total failure

Date Reported: 4/22/2008 11:08:28 AM

Severity: Commonly encountered problem

Last Updated: 3/20/2012 2:24:39 AM

Platform: All platforms

Internal Tracking #: 259621

Resolution: Fixed (Resolution Comments)

Resolved in Build: : 12.0.3136.15942

Duplicate of: None

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Total Votes: 10

Description

When trying to debug a program Delphi came up with an exception in Thread.Suspend. I was surprised to find that call in the call stack of LoadDesktop because when using that function you'll very likely run into deadlocks and access violations. Please use a proper synchronisation object instead of SuspendThread.

Apart from the warnings in the Platform SDK:
If the thread that is to be suspended happens to be suspended while using the heap, you will deadlock. Remember that the heap is a threadsafe object. In that case the thread might own a critical section or another synchronization object.

2003f2d3 +03f rtl100.bpl         Classes     10236  +5 Classes.TThread.Suspend
209df443 +01b coreide100.bpl     Desktop      1493  +1 Desktop.TDesktopStates.LoadDesktop
209df5c4 +06c coreide100.bpl     Desktop      1553  +9 Desktop.TDesktopStates.LoadRuntimeDesktop
209df756 +03a coreide100.bpl     Desktop      1582  +4 Desktop.TDesktopStates.ProcessCreated

I'm sure that this will be the reason for a deadlock in the IDE.

Windows SDK:
This function is primarily designed for use by debuggers. It is not intended to be used for thread synchronization. Calling SuspendThread on a thread that owns a synchronization object, such as a mutex or critical section, can lead to a deadlock if the calling thread tries to obtain a synchronization object owned by a suspended thread.

Steps to Reproduce:

Attach a debugger to the IDE, set a breakpoing in TThread.Suspend. Then switch the IDE Desktop or start debugging a program. TThread.Suspend should not be called.

Workarounds

None

Attachment

None

Comments

Markus Humm at 4/22/2008 11:17:39 PM -

Marked as needs attention

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