First, my example was fcntl(2), which musl is emulating. So that doesn't fit your "rule". Second, is your "rule" documented anywhere for musl? That's what I'm

First, my example was fcntl(2), which musl is emulating. So that doesn't fit your "rule". Second, is your "rule" documented anywhere for musl? That's what I'm looking for - an indication by the musl project that such a thing is supported (binary compatibility from newer to older Linux kernels, and if so, what version range). Without such a project-sanctioned statement, I'm afraid I stand by my position that the blog's assertion that the statically-linked rust-musl binary can be copied to any Linux 2.6.x machine (or newer) and just run without any issues. I would agree that any statically-linked rust-musl binary could be built on a Linux kernel and then run on a later Linux kernel, but earlier, well that's up to the musl project to say.