Typically by simply not having important data structures like that in untrusted memory. You're either dealing with raw, fairly untyped buffers, or structs that

Typically by simply not having important data structures like that in untrusted memory. You're either dealing with raw, fairly untyped buffers, or structs that get marshalled into kernel space from user space before even being validated. I did hear about some similar TOCTOU bugs though with seccomp filtering, that then required a fix to move the marshalling to happen before the BPF filter was run.