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

From: Mauricio Lin
Date: Wed Aug 16 2006 - 18:17:21 EST

Hi Catalin,

I have tested your latest kernel memory leak detector on my ARM device
and for curiosity I have checked some part of your patch to figure out
how the memory is scanned and compared to radix tree for detecting
orphan pointer.

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?

If this is possible, during the "for (ptr = start; ptr < end; ptr++)
{} " loop in the __scan_block(), the ptr variable can assume the
address 0xb7d73000 and the radix_tree_lookup() returns the
corresponding memleak_pointer and thus such pointer to this memory
area is not considered orphan (indeed it is an orphan pointer), right?


Mauricio Lin.
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