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Re: Please test pending bugfix release of base


From: Richard Frith-Macdonald
Subject: Re: Please test pending bugfix release of base
Date: Sat, 18 Jun 2011 17:03:40 +0100

On 18 Jun 2011, at 16:07, Quentin Mathé wrote:

> I found a bug with NS(Concrete)PointerFunctions, it looks a bit weird. So I'm 
> not entirely sure it's a bug in GNUstep Base.
> I'm using GNUstep Base from trunk (r33310), libobjc2 (the lastest revision) 
> from trunk. Everything is compiled with Clang 2.9 on Ubuntu 10.4 x86 (32 
> bits).
> 
> As visible with the test tool when run inside GDB, -initWithOptions: receives 
> a completely corrupted arguments (including self), but returns a valid self, 
> so the issue is not visible until much later (when pointerFunctionsXXX() are 
> called).  
> For example… If I create a NSMapTable initialized to accept raw pointers, 
> when a raw pointer is inserted as an object, the wrong acquireFunction is 
> called and a crash occurs.
> 
> At first sight, I also see no problems when invoking  methods other than 
> -initWithOptions: on NS(Concrete)PointerFunctions. 
> 
> The test program is available in attachment, here is a debug session that 
> shows how -initWithOptions: goes wrong:
> 
> [Thread debugging using libthread_db enabled]
> [New Thread 0xb7fe0b70 (LWP 16396)]
> 2011-06-18 16:32:23.318 pfunc-issue[16393]  ---> Alloc 
> <NSConcretePointerFunctions: 0x80f4c50>
> 2011-06-18 16:32:23.322 pfunc-issue[16393]  ---> Init 
> <NSConcretePointerFunctions: 0x80f4c50>
> 2011-06-18 16:32:23.322 pfunc-issue[16393]  ---> Alloc 
> <NSConcretePointerFunctions: 0x80f4c50>
> 
> Breakpoint 1, -[NSConcretePointerFunctions initWithOptions:] (self=0x2, 
> _cmd=0x804b310, 
>    options=135220304) at NSConcretePointerFunctions.m:188
> ^^^^^^^^^^^^^^^^^^^^^
> 188   - (id) initWithOptions: (NSPointerFunctionsOptions)options
> (gdb) bt
> #0  -[NSConcretePointerFunctions initWithOptions:] (self=0x2, _cmd=0x804b310, 
>    options=135220304) at NSConcretePointerFunctions.m:188
> #1  0x08048ae6 in main (argc=1, argv=0xbffff4e4) at pfunc-issue.m:20
> (gdb) c
> Continuing.
> 2011-06-18 16:32:39.863 pfunc-issue[16393]  ---> InitWithOptions: 
> <NSConcretePointerFunctions: 0x80f4c50>
> [Thread 0xb7fe0b70 (LWP 16396) exited]
> 
> Any idea?


1. Your test program is fine on my CentOS system using the standard 
compiler/runtime.
2. The self=0x2 reported by gdb looks suspicions ... your test program uses 
NSPointerFunctionsOpaqueMemory as the options, and the numeric value of that 
constant is 2

So it *looks* like the compiler (or perhaps the runtime) might be passing the 
arguments incorrectly... I don't see how a bug in base could cause the 
arguments passed to the method to be wrong.


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