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Date: Thu, 25 Apr 2002 17:12:21 +0800
From: "Huo Zhigang" <zghuo@gatekeeper.ncic.ac.cn>
To: lkml <linux-kernel@vger.kernel.org>
Subject: Re: Re: what`s wrong?
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>On Apr 24, 2002  18:06 +0200, il boba wrote:
>> Is there anybody that can help me understand what`s wrong with this code?

>Yes, easily spotted a major problem without even reading the whole
>thing.

>> #define BUFSIZ 8192
>> 
>> int init_module()
>> {
>>  int err_frame[BUFSIZ];
>
>The entire kernel stack is only 8kB in size.  You have already killed
  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>a bunch of random memory by allocating this much memory on the stack.
>You allocated 4*8192 = 32kB on the stack here.
  
   Sure, the kernel stack is 8192 Bytes, but "err_frame[]" is a local variable. Does the kernel allocate memory for "err_frame[]" from the stack?? 

>> int init_err_frame(int err_frame[]) {
>>  int i, k = 0, j = 0;
>>  char buffer[BUFSIZ];
>
>Another 8kB on the stack here - further random corruption.
   Here, I think, err_frame[] as a function parameter  will take 8K in the kernel stack.
   Am I correct?
  
   Thank you.


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