[PATCH 2/6] xserver: Possible memory leaks, stricter option checks, UnInit (NewInputDeviceRequest)
hch at lst.de
Sat Mar 31 02:42:04 PDT 2007
On Sat, Mar 31, 2007 at 12:13:10AM +0200, Magnus Vigerl?f wrote:
> Can the xserver really start using the standard C library methods? I'm not so
> sure as the Xalloc do some really nifty things (mmap) for big allocations,
> and I do think they are needed to be kept like that.
At glibc uses mmap for malloc when it's beneficial aswell.
> I didn't thought of that specific case.. But I'm not sure how big loss that
> would be.. If there's only one pointer and that is null, then there's no
> problem unless the freed memory is accessed where we'll get a SEGV instead of
> (potentially) something fishy. The most common problem with double free is
> (in my experience) two different structures that holds a pointer to the same
> memory and in this case if the memory is freed from both structures we'll
> still have a double free with or without setting the pointer to NULL.
Exactly. What's much more helpful is to set the freed memory to a
poisoning pattern so that you can detect use after frees, the actual
pointer shouldn't be much of an issue.
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