Comment by withinboredom

Valgrind won’t show you leaks where you (or a GC) still holds a reference. This could mean you’re holding on to large chunks of memory that are still referenced in a closure or something. I don’t know what language or anything about your project, but if you’re using a GC language, make sure you disable GC when running with valgrind (a common mistake). You’ll see a ton of false positives that the GC would normally clean up for you, but some of those won’t be false positives.