Ouch, looks to me that .blend file is heavily corrupted… At least, that’s what I can guess from that backtrace:

Looks like some pointer in the file has ugly bad value?

I don't think the problem is so much the file, but rather it may be some kind of mishandling with weight painting or deformation? The crash occurs after I transferred weights from one model to the problem model. But when I instead just created the DEF-head group and then set it to 100% on all vertices, there were no problems.

Okay, I've made another repro file. This one does not produce the crash, but rather sets the stage for the trigger conditions. For this I have used a different model off of blendswap, since I do not yet intend for the character models to be available in public.

File:

1. Make some quick random change or select an object, then press CTRL-Z to undo.
2. Save the file (preferably a copy), then try to reload it.

@Sergey Sharybin (sergey): Check my previous comment, before yours.

@Zauber Paracelsus (zauberexonar), save and reload makes no changes to internal data structures. Same applies to selection and undo. So the file is still somewhat corrupted and not good for tracking down actual bug.

So your comment before mine doesn't actually help.

Actually, I should point out that the problem begins with using the Transfer Weights function in weight painting mode.

Furthermore, I should clarify that I've been using a development build of Blender, where the Transfer Weights function appears to have been overhauled.

I'm betting that I ran into a new bug introduced in the Transfer Weights function, especially since the crash/corruption issue does not occur when I use the 2.73 release build.

Further testing, and with new repro steps. It'll occur on ANYTHING you use Transfer Weights on.

New repro steps:

1. Create a new scene, using a development build of blender.
2. Create two cubes near one another
3. On one cube, add a single vertex group and assign weights.
4. Select the first cube, then shift-select the other cube.
5. Go into Weight Painting mode
6. Use the Transfer Weights function
7. Save, and then reopen the file.

@Bastien Montagne (mont29): I just freshly compiled blender from git this morning. The crash no longer occurs with the original model(s) I discovered it on. However, it continues to occur with a slight variation on the repro steps I posted above:

1. Create a new scene, using a development build of blender.
2. Create two cubes near one another
3. On one cube, add a single vertex group and assign weights.
4. Select the first cube, then shift-select the other cube.
5. Go into Weight Painting mode
6. Use the Transfer Weights function
7. Select any other object, then hit CTRL-Z

Further, it seems like it will only crash sometimes on a bad saved file, but doing step 7 above on that file repros a crash, as will attempting to Transfer Weights again, or trying to remove a vertex group. In fact, every other thing I do on that file, even something as innocuous as entering edit mode, will trigger a crash. So, perhaps there is an unfixed code path that still has the issue?

@Zauber Paracelsus (zauberexonar) cannot reproduce following steps you gave here… Unless you mean, you are still using a corrupted file? in this case, yes, even in a new scene issue will remain, but starting from scratch with startup file I get absolutely no crash here.

Issue repros on my build from just a couple hours ago that was compiled fresh off of git. However, the issue does not repro at all on the nightly I just downloaded.

Very weird :-/

what’s the hash shown on blender startup panel?

For the nightly, the hash is 6e97db7. For the build I compiled myself (where the issue still repros partially), there is no hash. This is the output from git on the command line:

[zauber@manjaro blender]$ git describe --tags
v2.73-rc1-328-gecc58da
[zauber@manjaro blender]$ git rev-parse HEAD
ecc58da8f1d110498e700b804cb44adba1145113

That is pretty much exactly the same code… no reason to have that difference in behavior.

Maybe make a full rebuild (make clean, then usual build command)?

Deleted my blender source directory entirely, and redownloaded everything from git so that I had a clean slate. Issue no longer repros.