[syslinux] [PATCH 2/2] core: Fix stack overflow when reloading config

Celelibi celelibi at gmail.com
Wed Feb 3 07:16:24 PST 2016

2016-02-01 11:14 UTC+01:00, H. Peter Anvin <hpa at zytor.com>:
> On 01/26/16 07:36, Celelibi via Syslinux wrote:
>> From what I've seen, I think there are memory leaks a bit everywhere.
>> And it's practically unavoidable since modules are always forcefully
>> unloaded instead of letting them gracefully terminate.
>> Then, as I already mentioned somewhere else, I think we would need a
>> global resource tracker so that when a module is unloaded (or
>> simili-unloaded if it stays in memory anyway as discussed above) its
>> allocated resources (memory, opened files etc) can be freed anyway.
>> That would, of course, not work for the resources allocated by the
>> core module, but that could help tracking the growth of the allocated
>> resource and thus help debug them.
> We actually *have* a resource tracker; the malloc() implementation is
> explicitly designed so it keeps track of the owner module in order to be
> able to purge the contents on module exit.  We would still do that, just
> as now, the only difference is that we wouldn't purge the readonly
> segment(s) of a module nor the backup copy of the read-write segment(s).

That's nice to hear. It then should be easier to implement something
to catch use-after-free bugs. I think I've seen some.

However, is there something similar for file descriptors? I also think
I've seen some file descriptors never closed.


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