mem-pool: invalidate memory on GF_FREE to aid debugging

Debugging where memory gets free'd with help from overwriting the memory
before it is free'd with some structures (repeatedly). The struct
mem_invalid starts with a magic value (0xdeadc0de), followed by a
pointer to the xlator, the mem-type. the size of the GF_?ALLOC()
requested area and the baseaddr pointer to what GF_?ALLOC() returned.

With these details, and the 'struct mem_header' that is placed when
calling GF_?ALLOC(), it is possible to identify overruns and possible
use-after-free. A memory dump (core) or running with a debugger is
needed to read the surrounding memory of corrupt structures.

This additional memory invalidation/poisoning needs to be enabled by
passing --enable-debug to ./configure.

Change-Id: I9f5f37dc4b5b59142adefc90897d32e89be67b82
Signed-off-by: Niels de Vos <ndevos@redhat.com>
Reviewed-on: http://review.gluster.org/10019
Reviewed-by: Venky Shankar <vshankar@redhat.com>
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Emmanuel Dreyfus <manu@netbsd.org>
Reviewed-by: Kaleb KEITHLEY <kkeithle@redhat.com>

0 files changed, 0 insertions, 0 deletions