Change Details

This change makes a couple changes that improve the stack error reports when using a large shadow granularity. Currently, with large shadow granularity, one frequently encounters the situation where there are many small objects on the stack that do not have redzones in between. If a buffer overrun occurs, Asan is unable to identify the context and will report an unknown crash. We improve on this by the following: - Always add a full redzone at the end of a stack frame. - When scanning the shadow memory to determine the error type, if all we've seen is partial right redzones, ignore them and keep scanning. This gives us good stack reporting for the common case above.

We were not doing that for large shadow granularity.

This change makes a couple changes that improve the stack error reports when using a large shadow granularity. Currently, with large shadow granularity, one frequently encounters the situation where there are many small objects on the stack that do not have redzones in between. If a buffer overrun occurs, Asan is unable to identify the context and will report an unknown crash. We improve on this by the following: - Always add a full redzone at the end of a stack frame. - When scanning the shadow memory to determine the error type, if all we've seen is partial right redzones, ignore them and keep scanning. This gives us good stack reporting for the common case aboveWe were not doing that for large shadow granularity.