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From: Bernhard Walle <bernhard@bwalle.de>
To: Leo Prasath <leo.prasath@gmail.com>
Cc: linux-kernel@vger.kernel.org
Subject: Re: Null pointer exception for local variables in stack with C++ kernel modules
Date: Tue, 04 Jan 2011 23:10:41 +0100	[thread overview]
Message-ID: <4D239AE1.10003@bwalle.de> (raw)
In-Reply-To: <AANLkTik_dFBq5=GDB3tmiN0N=hc1iaif0hv4URnm2f5b@mail.gmail.com>

Hello Leo,

Am 04.01.11 20:46, schrieb Leo Prasath:
> 
> I have integrated a C++ codebase which uses minimalistic features of c
> and followed the guidelines in
> http://pograph.wordpress.com/2009/04/05/porting-cpp-code-to-linux-kernel/
> to integrate with an existing C linux kernel module.
> It all works fine except for occassional very very weird NULL pointer
> exceptions.

Wild guess: Stack overflow. In the kernel the stack is very limited
(depends on the configuration and IIRC on the archtecture, but 4K is the
minimum IIRC) and in C++ it's possible and common to put larger objects
on the stack.

However, C++ isn't supported by the kernel developers and you're on your
own. Rewrite the code to use plain C.


Regards,
Bernhard

      reply	other threads:[~2011-01-04 22:10 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <AANLkTimH+xa3Na6Y+M=UNZSfjph5etyTtc=v2TMdqwHj@mail.gmail.com>
2011-01-04 19:46 ` Null pointer exception for local variables in stack with C++ kernel modules Leo Prasath
2011-01-04 22:10   ` Bernhard Walle [this message]

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