Re: [Discuss-gnuradio] Weird malloc/free crash in pm_remez.cc

[Mark Cottrell]

On Mon, Nov 25, 2013 at 3:03 PM, Josh Myer <address@hidden> wrote:

Hi all,

I’ve got an annoying crash in the current head of gnuradio.  It’s 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 that’s hosed in my environment.  Until someone else can confirm this, it’s 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.  (It’s 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 doesn’t look like it should be crashing in this code path.  The pointer it’s freeing is totally fine when I step through with gdb: the same as the malloc’d value, and no intervening free() calls, yet it’s still crashing when it gets free()’d.  When I move the free(Grid) line around, the crash follows it.  It doesn’t look like anything else is getting screwed up, so I don’t know what to make of this.

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