Weird malloc/free crash in pm_remez.cc

Hi all,

Ive got an annoying crash in the current head of gnuradio. Its
reproducible with the GRC file up at:

http://www.joshisanerd.com/am_demod_crash.grc

Does this crash for anyone else? If nobody else can repro, this is
probably something thats hosed in my environment. Until someone else
can confirm this, its probably not worth looking into for anyone else.

For me, the crash is at pm_remez.cc:698, the free(Grid) call in the
error handler. (Its coming from an error code of -2, which is probably
due to my putting in totally insane parameters or some such.)

The odd thing is that it doesnt look like it should be crashing in this
code path. The pointer its freeing is totally fine when I step through
with gdb: the same as the mallocd value, and no intervening free()
calls, yet its still crashing when it gets free()d. When I move the
free(Grid) line around, the crash follows it. It doesnt look like
anything else is getting screwed up, so I dont know what to make of
this.

(FWIW, my goal is to poke around at decoding RDS. Ive removed a lot of
stuff to get down to this minimal program that shows the problem. Ive
gotten the AM demod stuff sorta working in ipython, and am now trying to
port it back to gnuradio pointers on anything thats clearly wrong with
my design there would be appreciated.)

/jbm

On Mon, Nov 25, 2013 at 10:12 PM, Mark Cottrell
[email protected] wrote:

probably something thats hosed in my environment. Until someone else can
line around, the crash follows it. It doesnt look like anything else is
Discuss-gnuradio mailing list
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You set the audio passband in the AM Demod to 0, which is what’s
causing the problem. That’s a bogus passband value, though it
shouldn’t be causing a memory crash. We’ll have to protect against
this instead of just letting it crash.

Thanks for the report.

Tom

On Mon, Nov 25, 2013 at 3:03 PM, Josh M. [email protected] wrote:

https://lists.gnu.org/mailman/listinfo/discuss-gnuradio

I was able to reproduce your problem with the linked grc file. I’m
running
gnuradio 3.7.2git-171-g362b0fb6 in debian jessie, and I have absolutely
no
idea what would be causing it, sorry. At least now it seems as though
it
isn’t isolated to a problem with your environment.


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