>>>>> "dave" == Dave Jones <dave@denial.force9.co.uk> writes:
dave> Manfred Spraul <manfreds@colorfullife.com> wrote:
>> If you want to benchmark the code: disable SLAB_DEBUG_SUPPORT &
>> SLAB_STATS, otherwise you'll see a huge slowdown: double free detection
>> is now always on, and red zoning is also enabled (SLAB_FORCED_DEBUG).
dave> This reminded me of something I was curious about recently.
dave> What exactly is red-zoning? I understand slab-poisoning,
dave> but couldn't figure out what red-zoning actually does.
Normally red-zoning means to read/write protect one page (for
instance) the end of the stack, if you try to access that page (that
means that you need more stack that stimated), you will provoke a
segmentation fault. If you have stored the red-stack addresses, you
can indeed tell _which_ thread provokes the stack overflow, and you
can actuate in consecuence:
- kill the process
- kill the thread
- allocate a bigger stack
- ....
That is red-zonning aplicated to stacks. You can applicate a similar
technique in other situations.
Later, Juanp
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This archive was generated by hypermail 2b29 : Thu Jun 15 2000 - 21:00:16 EST