What can cause "corrupted double-linked list" error?

I am having problems with a fairly complex code. I wasn't able to produce a short snippet that reproduces the error, so I'll try to explain the problem in words.

The code crashes randomly with the error

*** glibc detected *** gravtree: corrupted double-linked list: 0x000000001aa0fc50 ***

Debugging showed that it comes from the line where the codes frees an object. There seems to be nothing wrong with the object. It exists, and I can access it's data at the time the error occurs. The object's destructor is tr开发者_如何学Civial and doesn't do anything.

So, I'm kind of stuck. In what kind of circumstances do you expect 'free' to fail?

Try running your program under Valgrind. It may point you to an earlier cause, whereas gdb is only breaking in where damage has already occurred.

As Warren said, Valgrind is usually the best way to find it. The doubly linked list is a base of usually network or binary data handlers, ie in QT QByteArray or QTcpSocket. I had the same thing today and it was because I had invalidated an object by deleting it off a map but had previously obtained pointers to data inside of it. It worked sometimes, sometimes not. The higher the load on the system the more likely it would crash.