Okay, let's see. The user is reporting an issue with Qemu not supporting the set_robust_list syscall. They provided a test program that uses this syscall and show that when running under Qemu (specifically RISC-V), the syscall fails with "Function not implemented". On native x64, it works. The problem is that Qemu's linux-user mode doesn't implement this syscall, which affects applications relying on robust mutexes, like in glibc and .NET. Looking at the categories: instruction, syscall, or runtime. The issue is about a missing syscall implementation in Qemu. The bug is in Qemu's syscall handling. So the correct category is "syscall". syscall