# Weird malloc/free crash in pm\_remez.cc **URL:** \ **Category:** GNU Radio\ **Created:** [November 25, 2013, 3:04am UTC](https://www.ruby-forum.com/t/weird-malloc-free-crash-in-pm-remez-cc/237697 "2013-11-25T03:04:18Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![musicdenotation](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/ea666f/32.png) [@musicdenotation](https://www.ruby-forum.com/u/musicdenotation)\ **Post date:** [November 25, 2013, 3:04am UTC](https://www.ruby-forum.com/t/weird-malloc-free-crash-in-pm-remez-cc/237697/1 "2013-11-25T03:04:18Z")
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](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 ---
**Author:** ![skiz](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/e99b99/32.png) [@skiz](https://www.ruby-forum.com/u/skiz)\ **Post date:** [November 26, 2013, 4:31am UTC](https://www.ruby-forum.com/t/weird-malloc-free-crash-in-pm-remez-cc/237697/2 "2013-11-26T04:31:34Z")
On Mon, Nov 25, 2013 at 10:12 PM, Mark Cottrell [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) 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 > > This email, including any attachments, is only for the intended recipient. > > damage or interfere with recipient data, hardware or software. The recipient > > relies upon its own procedures and assumes all risk of use and of opening > > any attachments. 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 ---
**Author:** ![skiz](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/e99b99/32.png) [@skiz](https://www.ruby-forum.com/u/skiz)\ **Post date:** [November 26, 2013, 4:14am UTC](https://www.ruby-forum.com/t/weird-malloc-free-crash-in-pm-remez-cc/237697/3 "2013-11-26T04:14:02Z")
On Mon, Nov 25, 2013 at 3:03 PM, Josh M. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > [Discuss-gnuradio Info Page](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. – * * * This email, including any attachments, is only for the intended recipient. It is subject to copyright, is confidential and may be the subject of legal or other privilege, none of which is waived or lost by reason of this transmission. If you are not an intended recipient, you may not use, disseminate, distribute or reproduce such email, any attachments, or any part thereof. If you have received a message in error, please notify the sender immediately and erase all copies of the message and any attachments. Unfortunately, we cannot warrant that the email has not been altered or corrupted during transmission nor can we guarantee that any email or any attachments are free from computer viruses or other conditions which may damage or interfere with recipient data, hardware or software. The recipient relies upon its own procedures and assumes all risk of use and of opening any attachments.