What represents the callstack shown in NSight when opening a nv-gpudmp?

Hi,
Documentation question here.
We got a GPU page fault that generated a nv-gpudmp file thanks to Aftermath, along with other useful data.
When I opened the dump, I clicked on a callstack that was resolved after the symbols were provided.

What represents the callstack ?
Does it show the call that eventually led to the GPU page fault ?
How Aftermath is able to get this information since the GPU crash occurred asynchronously and way after the driver call was made ?
Thanks for your help
Ludovic