Bug #12685

malloc error: pointer being freed was not allocated

Added by eike.rb (Eike Dierks) almost 3 years ago. Updated over 2 years ago.

Target version:
ruby -v:
ruby 2.3.1p112 (2016-04-26 revision 54768) [x86_64-darwin15]


ruby crashed

  • never seen that before
  • should never happen
  • looks serious to me

I'm using ruby 2.3.1p112 (2016-04-26 revision 54768) [x86_64-darwin15] from macports

I was running rails in dev mode.
The bug happened while reloading a page (like we all do a thousand times a day)

Error message in the shell was:
(12416,0x70000071a000) malloc: *** error for object 0x1c7fdde49ddcc0: pointer being freed was not allocated
See the dump attached.

This might either be a very serious bug,
or a bug in my hardware.

I must admit that I did see a sign that might point to me having a faulty RAM.
(a wrong rendering in a window's backing store)
But that was in EyeTV (a wrong rendering in a window's backing store)
(It is well known that EyeTV is a very buggy C++ software)

So I assume that having these two bugs within two days
might be more of an conincidence (and not caused by faulty ram)

So this might be a false alarm, but maybe it is not:

Please look at the backtrace, it crashed in:

6 libruby.2.3.0.dylib 0x0000000109da0b23 obj_free + 684
7 libruby.2.3.0.dylib 0x0000000109da049a gc_sweep_step + 473
8 libruby.2.3.0.dylib 0x0000000109d9f61a newobj_slowpath + 374
9 libruby.2.3.0.dylib 0x0000000109d9f484 newobj_slowpath_wb_protected + 20
10 libruby.2.3.0.dylib 0x0000000109d53177 ary_new + 66
11 libruby.2.3.0.dylib 0x0000000109d5d7fe flatten + 77
12 libruby.2.3.0.dylib 0x0000000109d5afd4 rb_ary_flatten_bang +

While a faulty bit could crash it anywhere
(and this must be a heavily exercised routine)

Please forget about faulty bits and alpha particles
(my machine is running perfectly stable)

It might actually be a software bug in the gc.

I fear this will be hard to reproduce,
but maybe the stack trace might help you.

I believe this to be a software bug in the gc (which is very serious)
(please read the trace)


malloc_free_bug_backtrace.txt (43.9 KB) malloc_free_bug_backtrace.txt eike.rb (Eike Dierks), 08/17/2016 06:18 PM


Updated by shyouhei (Shyouhei Urabe) over 2 years ago

  • Status changed from Open to Feedback

Yes, it sounds serious. But so far I'm not successful in reproducing the error. Can you show us a bit more detailed instruction how to actually see this bug on my machine?

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