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?

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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.

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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.