Re: Some issues about the kernel memory leak detector: __scan_block() function

From: Mauricio Lin
Date: Thu Aug 17 2006 - 09:58:03 EST

Hi Catalin,

On 8/17/06, Catalin Marinas <catalin.marinas@xxxxxxxxx> wrote:
Hi Mauricio,

On 16/08/06, Mauricio Lin <mauriciolin@xxxxxxxxx> wrote:
> Let's suppose the a kmalloc() was executed without storing the
> returned pointer to the memory area and its fictitious returned value
> would be the address 0xb7d73000 as:
> kmalloc(32, GFP_KERNEL); // Cause memory leak
> Is there any possibility the __scan_block() scans a memory block that
> contains the memory area allocated by the previous kmalloc?

That's what the memleak-test module does.

Yes, there is a chance and this is called a false negative. If there
is a (non-)pointer location having this value (especially the stack),
it won't be reported. However, these locations might change and at
some point you will get the leak reported.

Do you mean that the (non-)pointer location might be moved to another
memory location?

Let's say that the fictitious address 0xb7d73000 can be changed to
another memory address, right?


Mauricio Lin.
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