RE: [PATCH] mm: optionally disable brk()

[David Laight]

From: David Hildenbrand
> Sent: 02 October 2020 18:52
> 
> On 02.10.20 19:19, Topi Miettinen wrote:
> > The brk() system call allows to change data segment size (heap). This
> > is mainly used by glibc for memory allocation, but it can use mmap()
> > and that results in more randomized memory mappings since the heap is
> > always located at fixed offset to program while mmap()ed memory is
> > randomized.
> 
> Want to take more Unix out of Linux?
> 
> Honestly, why care about disabling? User space can happily use mmap() if
> it prefers.

I bet some obscure applications rely on it.

Although hopefully nothing still does heap allocation
by just increasing the VA and calling brk() in response
to SIGSEGV.

	David

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